UNIVERSITY OF CALIFORNIA PUBLICATIONS. 
 
 COLLEGE OF AGRICULTURE. 
 
 AGRICULTURAL EXPERIMENT STATION. 
 
 MANUFACTURE OF DRY WINES IN 
 HOT COUNTRIES. 
 
 By FREDERIC T. BIOLETTI. 
 
 BULLETIN No. 167 
 
 (April, 1905.) 
 
 SACRAMENTO: 
 
 W. W. SHANNON, I : : SUPERINTENDENT OF STATE PRINTING. 
 
 1905. 
 
 / 
 
BENJAMIN IDE WHEELER, Ph.D., LL.D., President of the University. 
 
 EXPERIMENT STATION STAFF. 
 
 E. W. HILGARD, Ph.D., LL.D., Director and Chemist. 
 
 E. J. WICKSON, M.A., Horticulturist. 
 
 W. A. SETCHELL, Ph.D., Botanist. 
 
 ELWOOD MEAD, M.S., C.E., Irrigation Engineer. 
 
 C. W. WOODWORTH, M.S., Entomologist. 
 
 R. H. LOUGHRIDGE, Ph.D., Agricultural Geologist and Soil Physicist. (Soils and Alkali.) 
 
 M. E. JAFFA, M.S., Assistant Chemist. (Foods, Nutrition.) 
 
 G. W. SHAW, M.A., Ph.D., Assistant Chemist. (Starches, Oils, Beet-Sugar.) 
 
 GEORGE E. COLBY, M.S., Assistant Chemist. (Fruits, Waters, Insecticides.) 
 
 RALPH E. SMITH, B.S., Plant Pathologist. 
 
 A. R. WARD, B.S.A., D.V.M., Veterinarian, Bacteriologist. 
 
 E. W. MAJOR, B.Agr., Animal Industry. 
 
 A. V. STUBENRAUCH, M.S., Assistant Horticulturist, in charge of Substations. 
 
 E. H. TWIGHT, B.Sc, DiplomS E.A.M., Viticulturist. 
 
 F. T. BIOLETTI, M.S., Viticulturist. 
 
 WARREN T. CLARKE, B.S., Assistant Field Entomologist. 
 
 H. M. HALL, M.S., Assistant Botanist. 
 
 H. J. QUAYLE, A.B., Assistant Entomologist. 
 
 GEORGE ROBERTS, M.S., Assistant Chemist, in charge Fertilizer Control. 
 
 C. M. HARING, D.V.M., Assistant Veterinarian and Bacteriologist. 
 
 C. A. COLMORE, B.S., Clerk to the Director. 
 
 R. E. MANSELL, Foreman of Central Station Grounds. 
 
 JOHN TUOHY, Patron, ) 
 
 r Tulare Substation, Tulare. 
 JULIUS FORRER, Foreman, ) 
 
 J. E. McCOMAS, Patron, Pomona, ^ 
 
 J. W. MILLS, Superintendent, Pomona, I 
 
 y Southern California Substation. 
 •In charge Cooperation Experiments of Southern California, 
 
 JOHN H. BARBER, Assistant Superintendent, Ontario, 
 
 J. W. ROPER, Patron, 
 
 . University Forestry Station, Chico. 
 HENRY WIG HTM AN, In charge, 
 
 ROY JONES, Patron, ) 
 
 _. . >• University Forestry Station, Santa Monica. 
 
 WM. SHUTT, Foreman, \ 
 
 H. O. WOODWORTH, M.S., Foreman of Poultry Station, Petaluma. 
 
 77i£ Station publications (Reports and Bulletins), so long as avail- 
 able, will be sent to any citizen of the State on application. 
 
 V 
 
 X 
 
CONTENTS. 
 
 Page. 
 
 INTRODUCTION 5 
 
 METHODS FOR IMPROVING MANUFACTURE OF DRY WINES IN HOT 
 
 CLIMATES 10 
 
 AMELIORATION OF THE CHARACTER OF THE RAW MATERIAL 10 
 
 Varieties of Grapes . 10 
 
 Time of Gathering the Grapes 12 
 
 Methods of Cultivation 15 
 
 Pruning; Irrigation; Fertilization 15 
 
 More Complete Utilization of the Substances of the Grape 17 
 
 Effect of high temperature in making dry wine 19 
 
 Extraction of color and tannin 22 
 
 Addition of Substances Deficient in the Grapes 27 
 
 Water; Tartaric acid; Citric acid; Plaster; Phosphates 28 
 
 CONTROL OF FERMENTATION 33 
 
 Modifying the Temperature .___' 33 
 
 Physical Cooling Devices 34 
 
 Aids to radiation ; Attemperators and refrigerators ; Ice 35 
 
 Chemical Cooling Devices 44 
 
 Sulfur ; Sulfites 45 
 
 Postponement of Fermentation until Winter 51 
 
 Fermentation in Cool Locality 52 
 
 Control of Fermentative Agencies 53 
 
 SUMMARY 57 
 
 Methods Adopted in Southern France and Algeria 57 
 
 Conclusions 63 
 
MANUFACTURE OF DRY WINES IN HOT 
 COUNTRIES. 
 
 By FREDERIC T. BIOLETTI. 
 
 [This bulletin is the outcome of a recent visit, made under the auspices of the 
 University, to some of the chief vine-growing regions of Europe and Algeria. 
 
 This visit was undertaken during the months of October, November, and December, 
 1904, and its main object was to study the many changes which have been introduced 
 in recent years into French methods of grape-growing and wine-making. As it was 
 impossible, in the time available, to cover the whole of the ground thoroughly, my 
 attention was directed mainly to those subjects which seemed of most immediate 
 interest to the University and to the committee of California grape-growers who con- 
 tributed part of the necessary expenses of the trip. 
 
 In accordance with this idea, my observations had to do chiefly with the methods of 
 wine-making peculiarly adapted to hot climates, and with the methods of viticultural 
 and cenological education in vogue in France. Other matters of interest to Californian 
 viticulture were given as much attention as was possible without interfering with these 
 two main objects. 
 
 The principal educational institutions visited were the " Kgl. Lehranstalt fur Wein, 
 Obst und Gartenbau " at Geisenheim on the Rhine, the " Institut Nationale Agro- 
 nomique" at Paris, the "Ecole Nationale de Grignon" near Versailles, the " Ecole 
 Nationale de Montpellier" in the south of France, and the "Ecole Pratique d'Agri- 
 culture d'Ecully " near Lyons. At all of these, especial attention is given to instruction 
 in viticulture and cenologj r . 
 
 Experiment stations and research laboratories devoted more or less exclusively to the 
 same subjects were visited at Nancy, Epernay, Villefranche, Nimes, Montpellier, Nar- 
 bonne, Perpignan, Toulouse, Bordeaux, and Algiers. Visits were made to the depart- 
 mental professors of agriculture at these centers and to vineyards and cellars in the 
 Rheingau, Champagne, Burgundy, Beaujolais, Cotes du Rhone, H6rault, Gard, Nar- 
 bonnais, Roussillon, M£doc, and Algeria ; the greater part of the time being spent in 
 the Midi and in Algeria. My investigation was very much facilitated by the great 
 courtesy and assistance received everywhere from investigators and proprietors. My 
 thanks are especially due, among many others to: Professor Dr. Wortmann, Director 
 of Geisenheim; M. Pierre Viala, Inspecteur General de la Viticulture at Paris; M. L. 
 Ravaz, Professor of Viticulture at Montpellier; and M. Roger Mares, Departmental 
 Professor of Agriculture at Algiers. 
 
 I was much assisted in my investigations by the advice and encouragement of 
 members of the California Viticultural Club, notably of Messrs. Percy L. Morgan and 
 Frank T. Swett, without whose aid the scope of the work would have been very limited.] 
 
 INTRODUCTION. 
 
 It is a remarkable but well-recognized fact that in the regions where 
 the vine nourishes best, that is, where it yields the maximum crop for 
 the minimum labor, the greatest difficulties are encountered in the 
 manufacture of sound dry wines. In a general way it may be said that 
 nearly all the fine dry wines of the world are produced in regions such 
 as those of the Gironde, Burgundy, and the Rhine, where the climate is 
 relatively cool and where the vine does not attain its fullest develop- 
 
b UNIVERSITY OF CALIFORNIA— EXPERIMENT STATION. 
 
 merit either of growth or of crop. In the warmer and more productive 
 regions, if wines of superior quality are made they are usually sweet or 
 of sherry type. The dry wines of these regions are of two general 
 types, (a) thin watery wines, such as those of the south of France, whose 
 main value lies in their cheapness, and (b) heavy, coarse wines valu- 
 able for blending, such as those imported into France in large quantities 
 from Spain, Algeria, and elsewhere. The wines of the latter type are 
 not only defective in quality, but very commonly unsound, and large 
 quantities, in the aggregate, spoil before they reach the hands of the 
 wine merchant and become a total loss or are made into inferior brandy. 
 This loss would be much greater but for the use of the antiseptics 
 which are freely employed wherever the practice is not prevented by 
 effective pure-food laws. Before discussing the question as to whether 
 the wines of the warmer regions can be improved, and, if so, what are 
 the most practical methods, a clear understanding of the nature of their 
 defects and the causes of these defects is necessary. 
 
 The quality of a wine depends on two groups of factors: (a) those 
 which have to do with the nature of the raw material, that is, the char- 
 acter of the grapes; and (b) those which have to do with the way in 
 which this raw material is treated, that is, the character of the methods 
 of manufacture. Each of these groups of factors influences the other, 
 so that it is often difficult to decide whether certain qualities of a wine 
 are due to the character of the grapes, or to the way in which they 
 have been handled in the process of manufacture. For example, a 
 wine is deficient in color: this may be due either to a lack of coloring 
 matter in the grape or to an imperfect method of manufacture which 
 has failed to properly utilize the coloring matter present. Again, if a 
 wine is spoiled by bacterial fermentation, the cause may lie in careless, 
 uncleanly methods of manufacture, or in a lack of due acidity in the 
 grapes, which favored the growth of bacteria. In this way nearly all 
 the qualities of a wine are influenced, both by the character of the raw 
 material and by the method of manufacture; and a defect in either 
 may often be neutralized to a great extent by a corresponding change 
 in the other. 
 
 The relative importance of these groups of factors is a matter on 
 which the opinion of wine-makers has been greatly modified during the 
 last ten or fifteen years. Formerly, the first group was considered of 
 overwhelming importance and certain regions were considered totally 
 unfit for the production of sound dry wine, on account of the supposed 
 unsuitable nature of the grapes grown there. Yet many of these regions 
 produced the finest, largest, and best flavored table and raisin grapes. 
 Now. while the qualities desirable in an eating grape are not the same 
 as those necessary for a wine-making grape, there is no doubt that the 
 main reason for the failure to produce good dry wines in the plains of 
 
MANUFACTURE OF DRY WINES IN HOT COUNTRIES. 7 
 
 Algeria or the San Joaquin Valley does not lie in the qualities, either 
 negative or positive, of the grapes, but in the attempt to make ivines in 
 a hot climate by methods suited only to a cool one. 
 
 It is worthy of note that in the regions that have been famous for 
 the production of fine wines, such as Medoc, Rheingau, and Burgundy, 
 the finest and highest-priced wines are produced on warm, dry hill 
 slopes, and in years when the summer is exceptionally warm and dry- 
 This is equivalent to saying that the finest wines of these regions are 
 produced in situations where the soil conditions approach most nearly 
 to those of California vineyards, and in seasons when the weather dur- 
 ing the growing and ripening period of the grape approaches most 
 nearly to the California climate. In fact, the more nearly the chemical 
 composition of the grapes of the Rhine and the Gironde approaches 
 that of California grapes, the higher the quality of the wine and the 
 higher the price it brings in the market. Yet it is perfectly true that 
 it is only exceptional and apparently accidental when our California 
 wines equal or approach the quality of the best wines of the above 
 regions. 
 
 If the composition of the raw material is approximately the same, the 
 quality of the manufactured material ought not to differ much unless 
 the conditions of manufacture are different. It is doubtless in the fail- 
 ure to make these conditions identical or equivalent that the chief 
 difficulty lies. The use of the same methods does not result in realizing 
 the same conditions in a hot climate as in a cool one, and whatever the 
 summer temperature of the Gironde may be, the temperature of the 
 autumn, when wine-making takes place, is always very much cooler 
 than it is here. Many of the defects of our wines which were supposed 
 to be due to inherent faults of the grapes have been shown to be due to 
 bacterial and defective yeast fermentation, and to be completely under 
 the control of a suitable method of wine-making. This does not mean 
 that the locality where the grapes are grown is without influence, or 
 that it will ever be possible to produce a Chateau Lafitte or a Schloss 
 Johannisberg in Herault or Tulare. It does mean, however, that 
 wherever grapes mature a perfectly sound wine of good quality can be 
 made, and that throughout the great central plain of California sound 
 dry wines can be produced in unlimited quantities, superior in quality to 
 the great bulk of European wines. 
 
 The average sugar-contents of the grapes of the plains of southern 
 France will probably not exceed 16%, while that of the grapes of the 
 San Joaquin will be approximately 20%. There is a corresponding 
 superiority in other ingredients such as body and tannin; in every- 
 thing, in fact, except acidity and perhaps color. The first of these 
 defects can be remedied legitimately and without any great expense arti- 
 ficially, while the second can be minimized by proper methods of wine- 
 
8 UNIVERSITY OF CALIFORNIA— EXPERIMENT STATION. 
 
 making and by a suitable choice of varieties. Taking these facts into 
 consideration, then, 16 tons of grapes in the San Joaquin Valley are 
 about the equivalent for wine-making purposes of 20 tons in the plains 
 of the Midi. The importance of this is proved by the many attempts 
 being made to increase the alcoholicity of the wines of southern 
 France,* and by the fact that the most effective method at present 
 seems to be a partial concentration of the grapes, by which 20% or 30% 
 of the water is evaporated before they are made into wine. This is 
 equivalent to a reduction in volume of 20 tons to 16 or 14 tons. By 
 this means, from 20 tons of grapes is made about 2,400 gallons of full- 
 bodied wine, suitable for export or blending, having say 12% of alcohol, 
 instead of 3,200 gallons of thin, weak "vin ordinaire," with only 9% of 
 alcohol. With a corresponding 20 tons of Fresno grapes it should be 
 possible to make, without the expense of concentration, 3,200 gallons of 
 wine equal in quality to the 2,400 made from the same quantity of 
 French grapes. That this has not been done, or done only exceptionally 
 and accidentally, is, I believe, not the fault of the grapes, but of the 
 methods of manufacture. Much of the dry wine which it is attempted 
 to make in the hot interior valleys of California spoils before it ever 
 reaches the consumer, or more usually is distilled or metamorphosed 
 into an inferior sweet wine. The dry wine at present made in this 
 region is to a great extent of very inferior quality, deficient in normal 
 acidity, tannin, color, aroma, and showing various defects, cloudiness, 
 acetic and butyric acid, mannite, etc., due to bacterial or other improper 
 fermentations. This state of things is so well recognized that most 
 wine-makers of the San Joaquin Valley have ceased to attempt to make 
 dry wine and turn all their grapes into the sweet wines for which the 
 region is so specially adapted. 
 
 The crisis to which the sweet-wine market is subject in years of 
 heavy production would be modified if it were possible to turn a cer- 
 tain part of the grape crop into dry wine. Many of the varieties of 
 grapes planted in the great valleys are moreover more suited to the 
 production of dry wines than of sweet. If the making of dry wine 
 is to pay, however, the results must be more under the wine-maker's 
 control and the quality must be higher than it has been in the past. 
 
 With regard to the certainty of control it is my firm belief that there 
 is no region in the world where the wine-maker can be so sure of making 
 every year a good, sound, dry wine of uniform quality as in the great 
 central plain of California. An opinion so opposed to the practical 
 results of the past was not arrived at without careful consideration, 
 and is based principally upon the methods and tendencies of modern 
 
 * " What we need to satisfy our markets is alcoholic, heavy-bodied, deeply colored 
 wines such :is are not produced by our modern methods of intensive cultivation." 
 " La Concentration des Vins," by L. Roos, Bordeaux, 1902. 
 
MANUFACTURE OF DRY WINES IN HOT COUNTRIES. 9 
 
 wine-making in Algeria and southern France and on the long and care- 
 ful tests conducted for many years by the Agricultural Experiment 
 Station of the University of California at the Fresno, Tulare, Amador, and 
 San Luis Obispo substations and the viticultural cellar and labora- 
 tories at Berkeley. To attain this desired result, however, requires very 
 considerable changes in the present methods of wine-making, and in 
 the course of this report an attempt will be made to show the essential 
 features of this necessary change. 
 
 The conditions upon which the quality of wine depend are: 
 
 First — Those which affect the nature of the raw material, viz. : variety 
 of grape, climate, soil, methods of cultivation (including pruning, 
 fertilizing, etc.), vine diseases, time of gathering. 
 
 Second — Those which depend on the methods of manufacture. These 
 methods may affect the wine in a great variety of ways. They may 
 modify its composition by means of the addition of various substances 
 which occur naturally in the grape, such as sugar, water, tartaric acid, 
 and tannin, or even of substances which do not occur there in appre- 
 ciable quantities naturally, such as citric acid and plaster. They may 
 cause a more or less perfect utilization of the substances in the grape, 
 and in this way control to a great extent the amount of color and 
 tannin, and even of alcohol and acid in the resulting wine. 
 
 It is in the control of the fermentation, however, that the methods of 
 manufacture have the most scope for affecting the quality of the wine 
 for good or ill. The character of the fermentation depends on four 
 main factors: (a) the composition of the grape; (b) the kind and num- 
 ber of micro-organisms (yeasts, molds, and bacteria) present; (c) the 
 temperature of the fermenting mass; and (d) the amount of aeration. 
 
 In accordance with these facts, the attempts at finding a solution to 
 the problem of the manufacture of sound, dry wine of good quality in 
 hot climates have been made along different lines, which are discussed 
 in the remaining portion of this bulletin. 
 
10 UNIVERSITY OF CALIFORNIA— EXPERIMENT STATION. 
 
 METHODS FOR IMPROVING MANUFACTURE OF DRY WINES IN HOT 
 
 CLIMATES. 
 
 A. Amelioration of the character of the raw material. 
 
 1. Suitable varieties of grapes. 
 
 2. Appropriate methods of cultivation. 
 
 3. Time of gathering grapes. 
 
 4. More complete utilization of the substances in the grapes. 
 
 5. Addition of substances deficient in the grapes. 
 
 6. Addition of substances not found normally in the grapes. 
 
 B. Control of fermentation. 
 
 (I) By modifying the temperature. 
 
 1. Cooling devices (physical). 
 
 2. Cooling devices (chemical). 
 
 3. Postponement of fermentation until winter. 
 
 4. Fermentation in a cool locality. 
 (a) Transportation of grapes. 
 
 b) Transportation of crushed grapes or must, 
 
 (c) Concentration of grapes for transportation. 
 
 (d) Drying grapes for transportation. 
 
 (II) By controlling the kind of fermentative agents present, 
 
 1. Sterilization (physical). 
 
 2. Sterilization (chemical). 
 
 3. Pure and selected yeasts. 
 
 AMELIORATION OF THE CHARACTER OF THE RAW MATERIAL. 
 
 VARIETIES OF GRAPES. 
 
 The proper choice of varieties of grapes to plant is the first essential 
 in the production of good dry wine in any climate, and is especially 
 necessary in one which is either cooler or hotter than the normal for 
 the growth of the vine. A variety which gives excellent results in one 
 climate is often quite useless in another. The grapes of Roussillon will 
 not ripen on the Rhine, and those of Burgundy will not bear paying 
 crops in Fresno. The Cabernet Sauvignon, the grape from which the 
 bulk of the Chateau wines of the Medoc is made, the highest-priced red 
 wines made anywhere, is said to produce an undrinkable wine in Algeria. 
 
 For this reason nothing very certain can be gathered regarding vari- 
 eties suitable for our hotter regions by noting which are planted in 
 other countries. Luckily, the long and complete series of variety tests 
 which the Agricultural College at Berkeley has made during the last 
 twenty years has solved this question very satisfactorily for most parts 
 of California, especially as to what varieties are most suitable for red 
 wine. A short summary of these results was published in the Report 
 of the College of Agriculture in 1898,* and it is interesting to see how 
 far they correspond with the experience and practice of southern French 
 and more particularly of Algerian growers. 
 
 * Partial report of Work of the Agricultural Experiment Station of the University of 
 California. Art., " Memoranda on Wine, Table, and Raisin Grapes," pp. 245-253. 
 
MANUFACTURE OF DRY WINES IN HOT COUNTRIES. 11 
 
 In the south of France very few varieties are planted on a large scale, 
 and the great bulk of the vineyards consists of Aramon. This is the 
 ideal grape for quantity, producing an abundance of thin watery wine 
 with good acidity and, though deficient in alcohol, color, body, and 
 flavor, without any positive defects and capable of improvement by 
 blending with suitable heavy wines such as those from parts of Algeria. 
 During the last few years of heavy production and increasing competi- 
 tion with "sugar wines" and with similar but superior wines from the 
 rich plains of Algeria, the Aramon has been much less profitable, and 
 there is a tendency now to plant grapes yielding a less watery product. 
 The principal of these are the Grand Noir (a kind of Bouschet), the 
 Petit Bouschet, and the Carignane. The last would be planted more 
 but for its susceptibility to fungous diseases. In higher and well- 
 drained land the Alicante Bouschet, which is recognized as the best of 
 the Bouschets, is planted, but on lower and richer soil it is found 
 extremely difficult to defend it from oidium and other fungous parasites. 
 A few Matarb, Mourastel, and Cinsaut are found, but not in large 
 quantities. For white wine the Aramon is used principally, together 
 with the Piquepoule and the Terret. 
 
 In Algeria at the present time hardly anything is planted except the 
 Carignane and Alicante Bouschet, which unite there, better than any 
 other varieties, productiveness with fair quality. Their susceptibility 
 to disease is more easily controlled in the drier climate of Algeria, but 
 they still require a certain amount of spraying. Other varieties grown 
 there, to some extent, are Cinsaut, Aramon, Mourastel, and Grenache 
 for red, and Farana for white wine. These, especially the first two, do 
 not give thorough satisfaction, on account of their lack of the color, body, 
 and alcohol which constitute the main value of Algerian wines. In the 
 higher regions, especially in the neighborhood of Miliaria, where the 
 best wines of the country are produced, a certain amount of Pinot and 
 Gamai vines are grown; but these are gradually giving way to the 
 Carignane, which produces much more abundantly. Very little seems 
 to have been done in experimenting with varieties other than those of 
 France. The vines of Burgundy and the Medoc have generally failed 
 to give the desired results in either quality or quantity, and the varie- 
 ties adopted are those among the southern French grapes which suit 
 the conditions best. 
 
 In the report of the Agricultural Experiment Station referred to 
 above, the varieties recommended for the production of dry red wine in 
 the hotter parts of the San Joaquin Valley are Alicante Bouschet,* 
 Valdepefias, St. Macaire, Lagrein, Refosco, Barbera; and for the foot- 
 
 * This variety and the Petit Bouschet were distributed over California with exchanged 
 labels, and in this way became interchanged at the Experiment Stations. The remarks 
 in older reports, including the one referred to, regarding " Petit Bouschet," apply there- 
 fore to Alicante Bouschet. 
 
12 UNIVERSITY OF CALIFORNIA — EXPERIMENT STATION. 
 
 hills of the Sierra, Alicante Bouschet, Aramon, and Serine. There 
 seems no occasion at present to modify these recommendations, and it is 
 extremely desirable, if dry red wines are to be made in those regions, that 
 larger quantities of these varieties, especially of the first two, should be 
 planted instead of so much Carignane, Matarb, and Zinfandel, which 
 give much inferior results there, so far as regards quality, without a 
 sufficiently great compensation as regards quantity. For dry white 
 wine, the varieties recommended were Burger, Folle blanche, Aramon, 
 for the valley, and possibly Clairette for the foothills; but it is doubtful 
 if at present it is advisable to plant grapes for dry white wine in those 
 localities. That throughout the valley, dry red wines of quality equal 
 at least to those of the plain of the Metidja in Algeria can be produced 
 there can be little doubt, if a certain proportion of Valdepefias or any of 
 the other varieties recommended are grown to bring up the color, acid, 
 extract, and aroma of the varieties already planted, and if a system of 
 wine-making is adopted which will utilize the good qualities of the 
 grapes and neutralize the injurious effects of the high temperature of 
 the vintage season. 
 
 TIME OF GATHERING THE GRAPES. 
 
 The stage of ripeness at which the grapes are gathered has great influ- 
 ence on the character of the fermentation and the quality of the resulting 
 wine. Within certain limits the less mature the grapes, the more acid 
 and the less sugar will they contain, and the easier and more complete 
 will be the fermentation. For this reason the premature gathering of 
 the crop has been suggested and practiced as a means of avoiding dif- 
 ficult fermentations in hot regions. So far as the avoidance of " stuck" 
 wines is concerned the method is usually successful; but there is loss 
 in both quantity and quality, which in many cases more than counter- 
 balances the gain. 
 
 With regard to the quality of the wine, it is well known that the 
 best wine can be made only from grapes which have reached the stage 
 of maturity which is known as " wine-making ripeness." Before that 
 stage is reached the grapes not only contain substances which give a 
 disagreeable harshness to the wine, but have failed to elaborate those 
 other substances to which the finer flavors and aromas of good wine are 
 due. To a certain extent, this stage of ripeness is independent of the 
 degrees of sugar or acidity present, and can only approximately be deter- 
 mined by means of the mustimeter and acid test, or other analytical 
 means alone. While an Aramon in the south of France may have 
 attained its optimum degree of maturity for wine-making purposes when 
 it contains 16% of sugar, a Matarb in the Sacramento Valley may be still 
 far from ripe enough for the same purposes when it contains 20% of 
 sugar. 
 
MANUFACTURE OF DRY WINES IN HOT COUNTRIES. 13 
 
 We can not, therefore, gather our grapes prematurely without some 
 sacrifice of quality, and it is only in the absence of better means of 
 controlling the fermentation that it can be recommended. This loss 
 of quality can be minimized in many cases, however, while still retain- 
 ing the advantages. If instead of gathering all the grapes when they 
 are imperfectly mature, we allow the main part of the crop to reach 
 "wine-making ripeness" and then crush them with a suitable propor- 
 tion of very unripe grapes to enhance the acidity, we improve the fer- 
 mentation with less detriment to the quality. The ripe grapes contain 
 those substances necessary for the quality of the wine, and the unripe 
 those necessary for a good fermentation. This can be done only when 
 the ripe and the unripe grapes can be obtained at the same time, for it 
 is essential that they should be crushed and fermented together. The 
 two kinds of grapes may be of different varieties, ripening at different 
 epochs, or of the same variety, from early and late locations or localities. 
 One of the best methods of applying this remedy is to use the bunches 
 of second crop on the same vines. When the first crop has reached its 
 optimum degree of ripeness, the second crop of most varieties is just in 
 the right condition to correct the lack of acidity in the first. This 
 practice is largely employed in parts of Algeria, and also in South 
 Africa, with great success. The resulting wines, while showing a slight 
 "greenness" to the palate, are much superior in quality to those made 
 altogether from grapes gathered prematurely, while fermenting with 
 equal ease and completeness. 
 
 With regard to the loss in quantity some interesting conclusions may be 
 drawn from some recent French investigations.* These show an average 
 increase of volume in grapes of 2% per day during the two or three 
 weeks preceding maturity, and an increase of .7% per day of the sugar 
 during the same period. The actual figures noted vary within very wide 
 limits with different varieties of grapes and different localities, but the 
 average of all the results will doubtless give us an approximation to the 
 average in practice. If, then, we gather the grapes before they attain 
 the proper degree of maturity, we obtain a smaller quantity of wine of 
 a lower degree of alcohol. This loss may be considered as the cost of 
 the acid in the partially ripe grapes, to which the better fermentation 
 is due. If we compare this cost with that of a sufficient amount of tar- 
 taric or citric acid to attain the same result, we will find it much higher. 
 An example will make this clearer. If we have a vineyard where the 
 grapes at maturity contain 22% of sugar and .4% of acidity, we might, 
 by picking them a week before maturity, have sufficient acidity to insure 
 a thorough fermentation. At this time (using the figures given above) 
 the grapes would contain about 16.9% of sugar and ,6% of acidity, and 
 
 *Aime Girard et L. Lindet : " Recherches sur le developpement progressif de la grappe 
 de raisin." Paris, 1898. 
 
14 UNIVERSITY OF CALIFORNIA — EXPERIMENT STATION. 
 
 the quantity of bunches that at maturity would weigh 2,000 pounds 
 would at this time weigh only 1,780 pounds. The cost, then, of the 
 extra .2% of acidity that we would obtain may be reckoned as follows: 
 
 220 pounds of grapes, at $15 $1 65 
 
 90 pounds of sugar, at 3 cents 2 70 
 
 Total cost of acidity per ton of grapes $4 35 
 
 Reckoning the price of tartaric acid at 25 cents per pound, the cost 
 of this .2% of acidity would be only $1; and if citric acid were used, 
 the practically equivalent amount would cost even less. These figures 
 are merely approximate, and the difference in cost may often be less 
 than this; but it is just as likely to be more. 
 
 If, then, we consider the losses in both quality and quantity, it is 
 rarely if ever advisable to pick grapes prematurely for the purpose of 
 promoting a good fermentation; cheaper and better methods are usually 
 available. The principal exception is when a second crop is available 
 in the right condition when the first crop is being picked, especially 
 when this second crop is of a variety which can not be depended on in 
 the locality to attain full ripeness later. 
 
 Another point of practical importance regarding the time of gathering- 
 is worthy of notice. In large vineyards of one variety of grape or of 
 several ripening at about the same time, it is impossible to gather all the 
 grapes just at the most desirable stage of maturity. For this reason it 
 is usually necessary to commence gathering before the grapes have 
 quite reached this stage, and to continue after they have passed it. In 
 Algeria it is usual to commence the vintage as soon as the grapes are 
 capable of producing wine of 8% of alcohol, and before the vintage is 
 over they are usually sweet enough to produce wine of 12% to 14% of 
 alcohol. If all the fermentations are complete a good average wine is 
 made by blending all together. The high acidity of the early-gathered 
 grapes supplements the low acidity of the late-gathered grapes. Too 
 much acidity in the must is a much less serious defect than too little, as 
 much is deposited during fermentation, and more during the first few 
 weeks following. The cause of this is the presence of alcohol and the 
 fall of temperature, both of which conditions make the wine less capable 
 of holding the acid tartrates in solution. For this reason, when the 
 wine made toward the end of the season is deficient in acid it is desirable 
 to blend it with the early-made acid wine as soon as possible, before the 
 latter has deposited too much of its acidity. Some wine-makers in fact 
 mix the early-fermented wine with the over-ripe grapes when they are 
 crushed or when they have half fermented. This utilizes the surplus 
 acidity most effectually, and at the same time aids fermentation by 
 diluting the sugar and cooling the temperature of the later fermenta- 
 tions. The method has the defect, however, of entailing a, double 
 handling of a part of the wine, and exposing a wine which is already 
 
MANUFACTURE OF DRY WINES IN HOT COUNTRIES. 15 
 
 made and sound to the risks of a second fermentation under less favor- 
 able conditions than the first. 
 
 METHODS OF CULTIVATION. 
 
 The composition of the grapes, as well as the amount of the crop, can 
 be modified very considerably by the system of pruning, tillage, irriga- 
 tion, and manuring adopted. The old idea that the smaller the crop 
 the higher the quality of the wine is by no means always or even gen- 
 erally true. Anything which weakens the vine beyond a certain limit 
 will decrease its bearing capacity, and at the same time injure the quality 
 of the grapes. Vines weakened by disease, soil exhaustion, or lack of soil 
 moisture produce badly ripened grapes, deficient in sugar, acid, and 
 other elements which are necessary for the production of good wine. 
 This is especially true of any condition which prevents an abundant 
 growth of healthy leaves throughout the season. When the leaves cease 
 to perform their functions properly, the grapes cease to develop. For 
 this reason it is often possible, by appropriate cultural methods, to 
 increase the quantity of the crop, and at the same time to ameliorate 
 its quality. Anything which increases the size of the bunches and 
 berries without interfering with their normal ripening usually improves 
 their quality. This is particularly true in hot climates, where there is 
 ordinarily no lack of sugar in the grapes or where there is often too 
 much. 
 
 On the other hand, anything which increases the number of bunches 
 at the expense of the proper development of the individual berries 
 usually produces a deterioration in the quality; and often the increase 
 in quantity is more apparent than real, as small, badly developed grapes 
 yield comparatively little wine. 
 
 Pruning. — The larger and more vigorous a vine, the more grapes it is 
 capable of bringing to perfection. The more buds one leaves on a vine 
 in pruning, the more bunches it is enabled to produce. Our pruning 
 should be so calculated, therefore, as to give the vine the opportunity to 
 produce as many bunches as it can properly support and bring to the 
 desired degree of maturity. A vine pruned too long or given too many 
 spurs may yield a large number of bunches, but the grapes will be 
 deficient in juice, sugar, acid, and all the constituents essential for good 
 wine. Increasing the amount of bearing wood on a vine will increase 
 the crop only within certain limits. To pass these limits we must 
 strengthen the vine by improved tillage, irrigation, and fertilization. 
 An essential condition of both good crops and good wine is a strong 
 healthy vine. 
 
 Irrigation. — It was long believed that it was impossible to make 
 good wine from irrigated vineyards. But this is no more true than the 
 
16 UNIVERSITY OF CALIFORNIA— EXPERIMENT STATION. 
 
 equally widespread belief that irrigation is incompatible with the pro- 
 duction of other good fruit. Irrigation properly applied is in fact one of 
 the surest means of insuring both the quantity and quality of the crop, 
 as it gives the vine the amount of water it needs at the time it needs it. 
 It frequently occurs during the latter part of dry seasons, especially with 
 late ripening varieties such as Matarb, that the grapes suddenly cease to 
 develop either in size or sugar, in spite of the warm weather. This is 
 because the vegetation of the vine is arrested and the leaves and roots 
 fail to perform their functions properly. Grapes grown on a dry 
 hillside may, under such conditions, fail to develop more than 16% of 
 sugar, while the same variety in a moister soil with the same weather 
 conditions may reach 20%. Under such conditions irrigation, when 
 practicable, will remedy the trouble. Irrigation may also be used to 
 remedy the opposite condition, viz.: the development of too much sugar 
 in the grapes. Many convincing tests of summer irrigation of vines 
 have lately been made in southern France. Those of A. Muntz* are 
 particularly suggestive to Californians, as they were made in the Rous- 
 sillon, where the climate resembles more nearly that of California than 
 in any other part of France. In a series of twelve tests made with 
 Aramon and Carignane vines, late summer irrigation increased the 
 weight of grapes produced 29%, and the weight of sugar per acre 20%. 
 The average composition of the grapes from irrigated and from non- 
 irrigated vines was as follows: 
 
 Sugar. Acid. 
 
 Irrigated 18.8% 1.11% 
 
 Non-irrigated 19.6% .96% 
 
 The wine made from the irrigated grapes contained 11% of alcohol, 
 and that from the others 11.5%, but otherwise the quality was identical. 
 Calculating the value of the crop of wine at 2 francs per degree per 
 hectoliter — the market price at the time of the test, corresponding to 
 17^ cents per gallon for wine of 11% alcohol — the gain per acre due to 
 the irrigation was $20. There can be no doubt that in many cases the 
 gain in California from irrigation properly applied would be propor- 
 tionately greater where the grapes tend to produce too much sugar and 
 too little acid for proper fermentation. In many vineyards in the irri- 
 gated portions of California undoubtedly as much water as the vines 
 can profitably use is applied, and in some cases more; but no fear need 
 be entertained that irrigation will depreciate the quality of the wine if 
 it does not decrease the sugar-contents of the grapes below 19% (about 
 20.2%, Balling). There is far more danger that insufficient irrigation 
 
 * " De reflect des Arrosages Tardifs." A. Muntz, in "Revue de Viticulture," vol. 
 11, p. 541. 
 
 * M. G. BrSmond more than doubled his crop by judicious irrigation, at the same 
 time improving the quality and alcoholicity of his wine. " Progres Agricoleet Viticole," 
 vol. dZ t p. 897. 
 
MANUFACTURE OF DRY WINES IN HOT COUNTRIES. 17 
 
 in the hot interior valleys will result in grapes deficient in acid and 
 with excessive sugar, giving unsound and inferior wines. 
 
 The time of irrigation is of equal importance with the amount. It is 
 very important that the vine should have sufficient moisture available 
 during the period between what the French grape-growers call the 
 " Veraison " — (the time when the grapes, having attained almost their 
 full size, commence to color) — and full ripeness. During this period 
 there is a migration toward the fruit of materials accumulated in vari- 
 ous parts of the vine, and great changes take place in the composition of 
 the grapes. Growth relaxes in the leaves and shoots, which become paler. 
 It is a critical period in the maturing of the crop, and if the vine is 
 not well nourished and supplied with water it is not able to supply the 
 energy necessary for the profound chemical and physical changes taking 
 place in the fruit.* During the latter part of this period, which lasts for 
 from four to six weeks, it is very important that the vine should not 
 receive a check from lack of available moisture. It is often observed 
 in France and Algeria that when the autumn is hot and dry, the devel- 
 opment of the grapes is arrested and the crop is deficient not only in 
 quantity but often in sugar and acid. This explains the good effects 
 of late irrigation, which Muntz in Roussillon (already quoted) and 
 others in southern France have found so noticeable. 
 
 Fertilization. — With regard to the effect of fertilization on the quality 
 of the grapes, the same line of reasoning applies as with irrigation. A 
 starved vine will produce not only few grapes but inferior grapes, and 
 a fertilizer which will increase the crop will usually improve its quality; 
 and no deterioration of quality from this source need be feared so long 
 as the sugar-content of the grapes remains sufficiently high. Fertiliza- 
 tion of the vines is carried out very thoroughly and regularly in southern 
 France, and the best practice is considered to be an annual treatment. 
 The crop is very much increased by this means, often doubled without 
 sacrifice of quality, f 
 
 MORE COMPLETE UTILIZATION OF THE SUBSTANCES IN THE GRAPES. 
 
 Some of the defects of the wines of hot countries may be attributed, 
 not so much to deficiencies in the grapes, as to the failure to properly 
 utilize the materials present. The fermentation of red grapes with the 
 stems has been advocated as a means of increasing the body, acidity, 
 and tannin-contents of the wine. In the south of France this is the 
 common practice. The observed good effect is due, however, not to the 
 materials in the stems, but to those in the skins, which the presence of 
 the stems permits to be more thoroughly extracted. The good effects 
 of fermenting with the stems, then, are mainly indirect, and may be 
 
 * G. Foix: " Cours Complet de Viticulture," p. 267. 
 t Degrully: " Progres Agricole et Viticole," vol. 32, p. 669. 
 2 — BUL, 167 
 
18 UNIVERSITY OF CALIFORNIA— EXPERIMENT STATION. 
 
 obtained by any means which promotes the extraction of matters from 
 the skins, such as stirring, long maceration, etc. On the other hand, 
 the direct effect of the stems is to give a harshness to the wine which is 
 incompatible with the best quality, and the practice is advisable, there- 
 fore, only where very common wines are made. In Algeria the stems 
 are usually rejected, and the extraction of color and tannin from 
 the skins is promoted by pumping-over during the last stages of fer- 
 mentation. 
 
 In Algeria the use of cooling machines to moderate the heat of fer- 
 mentation, while almost completely successful in its object of enabling 
 the cellarman to be sure of producing a sound dry wine, has brought a 
 very serious trouble in its train. The main value of Algerian wines, 
 the special character which made them desirable to the wine merchants 
 of France, was their heavy body, high astringency, and deep color. 
 These three important qualities have all been modified by the cool fer- 
 mentations now practiced. Wines which are not allowed to exceed 90° 
 or 93° F. during fermentation, though they are usually sound and dry, 
 and free from those defects and diseases which used to characterize so 
 many Algerian wines, possess much less body, color, and tannin than 
 the wines made by the old method. The gain, therefore, of greater cer- 
 tainty in results and less spoiled wine is to a great extent offset by the 
 loss of much of the character which constituted the value of the old 
 wines when they were successfully made. It is beginning to be realized 
 now that too much emphasis has been placed on the ill effects of high 
 temperature in fermenting red wine, and the good effects of those tem- 
 peratures lost sight of. Attempts have therefore been made lately to 
 devise a system of wine-making which will combine the good effects of 
 high temperatures in the complete extraction of the grapes, and the good 
 effects of low temperatures in the complete fermentation of the wine 
 and the absence of injurious ferments. 
 
 The most notable system of this kind, and the only one in practical 
 use in Algeria, is that of M. Debono, a large wine-maker of Boufarik. 
 The results of the method were kindly shown at the cellar of M. Duroux 
 at Rouiba, where 200,000 gallons of wine were made by this method 
 last year. The wine, as seen in December, 1904, two months after 
 the vintage, was clear, dry and sound, and superior in color, body, and 
 taste to that of any other large cellar tasted in Algeria. The method 
 in brief is as follows: 
 
 1. The grapes are crushed and stemmed into amphoras* of 11,000 
 gallons capacity, with strainers at the bottom. 
 
 2. The must is then drawn off. This is done preferably immediately 
 after crushing, but in practice often after fermentation is half over. 
 
 *The amphoras used in Algeria for fermenting and storing wine arc vats shaped like 
 huge bottles, and constructed of concrete, masonry or brick, and lined with glass. 
 
MANUFACTURE OF DRY WINES IN HOT COUNTRIES. 19 
 
 3. This must is pumped into amphoras of 12,500 gallons capacity, 
 treated with sulfite to moderate the temperature, and allowed to fer- 
 ment until all but about 2% of the sugar has disappeared. 
 
 4. As soon as the must contains only 2% of sugar it is pumped back 
 on to the pomace in the original amphora. 
 
 5. The pomace in this amphora has meanwhile become very hot — 
 44°-45 c C. (111°-113° F.). 
 
 6. The must is now pumped over the hot pomace repeatedly until it 
 has extracted sufficient color and tannin, and is then pumped back into 
 the 12,500-gallon amphoras, where fermentation is completed. Usually 
 the wine is quite dry by the time it arrives in the larger amphoras the 
 second time. 
 
 The time of the operation from the crushing of the grapes until the 
 wine is placed in the final amphoras is usually about four days. The 
 method requires constant vigilance day and night. 
 
 The must should not be allowed to become quite dry before being 
 pumped over the pomace, or the wine will be inferior in color and 
 quality. On the other hand, it must not be pumped over with more 
 than 4% of sugar, or there is danger of a hot fermentation and its 
 accompanying effects. 
 
 By this method we get the good effects of hot temperature in the 
 pomace vat, where it macerates the skins and so enables the must to 
 extract the color, body, and tannin. At the same time we get the good 
 effects of low temperature in the must vats, where the wine becomes 
 dry and acquires the bouquet characteristic of cool fermentations. The 
 reason we do not get the bacterial fermentations usually accompany- 
 ing hot fermentations is probably because the great bulk of the wine 
 never becomes hot, and the yeast remains strong and healthy and 
 thoroughly defecates the wine before the bacteria have an opportunity 
 to injure it. In an ordinary hot fermentation the weakening of the 
 yeast has probably more to do with the growth of bacteria than the 
 favorable influence of the high temperature. There is undoubtedly 
 some loss of alcohol in the pomace vats, due to the very high tempera- 
 ture, but this is apparently more than offset by the gain in alcohol in 
 the cool must vats. I was assured that the wines fermented in this 
 way usually showed a higher degree of alcohol than those fermented 
 in the ordinary way. 
 
 Effects of High Temperatures. — The effects of various degrees of tem- 
 perature in the process of wine-making are of two kinds, which should 
 be carefully distinguished. They are: (1) Those which are due directly 
 to the degree of temperature and its immediate action on the must or 
 wine; and (2) those which are due indirectly to the degree of tempera- 
 ture through its modifying influence on the character and kind of the 
 micro-organisms present. It is, to a great extent, to a failure to prop- 
 
20 UNIVERSITY OF CALIFORNIA— EXPERIMENT STATION. 
 
 erly recognize this distinction that so much difference of opinion exists 
 as to the most favorable temperature for fermentation, and as to the 
 advisability of pasteurizing must or wine. 
 
 Under the ordinary conditions of wine-making; the second of these 
 groups of effects is by far the more important. That is, the great differ- 
 ences found in wines fermented at different temperatures between the 
 extremes of 20° C. (68° F.) and 40° C. (104° F.) are due principally to 
 the differences caused in the kinds and proportions of the various molds, 
 yeasts, and bacteria present, and to the different physiological activities 
 of these micro-organisms at various temperatures. The direct effects of 
 much wider ranges of temperatures than these, if not continued too long, 
 are in fact extremely slight, proportionally, in the case of must and, 
 when evaporation is prevented, of wine. Clear grape-must may be 
 subjected to any temperature between 0° C. and 80° C. (176° F.) for a 
 short time without any very appreciable effect on its appearance, flavor, 
 or chemical composition. The same is true of wine, if at the higher 
 temperatures the heating is done in such a way as not to cause evap- 
 oration of the alcohol. 
 
 Practically all the ill effects of a hot fermentation, i. e., production of 
 volatile acids and mannite, failure to convert all the sugar into alcohol, 
 disagreeable flavors, persistent cloudiness, etc., are due, not to the heat 
 itself, but to the bacteria, which multiply and flourish at high tempera- 
 tures, and to the weakened yeast, which at these temperatures becomes 
 abnormal and acts upon the must in a way very different from its normal 
 and healthy action. If, then, we heat a must to 40° C. (104° F.) arti- 
 ficially when there are no bacteria or yeasts present, none of these 
 undesirable results follow. The taste common in wine fermented at 
 high temperature, often described as a cooked taste, is not, therefore, 
 due to the heat directly, but to the action of bacteria, or perhaps to the 
 action of abnormal yeast.* A real cooked taste, that is, the taste 
 of caramelized sugar, may be given to must by heating it too high, 
 and this is in fact done in some processes of wine-making where the 
 must, or part of it, is concentrated by heating in boilers. It has been 
 shown experimentally, however, that must may be heated to 80° C.f 
 (176° F.) or even 90° C. (194° F.) without contracting this cooked taste 
 in the slightest degree. Where this taste is acquired at an apparently 
 lower temperature, it is due to the fact that, owing to the method of 
 heating over a fire or by means of superheated steam pipes, some of the 
 must is heated much higher than 90° C. and imparts a taste to the whole. 
 
 Another taste, undesirable in dry wines, often associated J with high 
 temperatures, is that of " rancio." This is the taste acquired by wines 
 upon exposure for a long time to the air. The taste is desirable in 
 
 * This is well shown in the experiments described on page 25. 
 
 t See U. C. Bull. 130, page 6. 
 
 X Barba, in "Annales de la Soci^te" des Viticulteurs de France," vol. VI, p. 96. 
 
MANUFACTURE OF DRY WINES IN HOT COUNTRIES. 21 
 
 ports, sherries, and other sweet and liqueur wines, and many processes 
 are used to facilitate and hasten its acquirement. All these processes 
 aim at increasing the oxidation of the wine, either by fuller exposure 
 to the air or by exposure at higher temperatures. This taste was at 
 one time accredited to the action of a fermentative organism, but it is 
 now well known to be due to simple direct oxidation. Must or wine ster- 
 ilized and kept in sterilized vessels in contact with the air acquires the 
 taste quite as quickly as when unsterilized. The factors which deter- 
 mine the amount of the taste and the rapidity with which it is acquired, 
 are the temperature and the exposure to the air. If we wish to prevent 
 the acquisition of "rancio," therefore, we must avoid undue aeration and 
 high temperatures. That exposure to high temperatures alone con- 
 tinued for a short time will not cause a wine to become " rancio" is 
 proved by the pasteurization of dry wines at 160° F. out of contact 
 with the air. It has also been proved that must may be exposed to the 
 same temperature under the same conditions with equal impunity. 
 Moreover, Professor Barba, of the CEnological Station at Nimes, has 
 shown that must and grapes can be heated to 70° C. (176° F.) in an 
 open vat for a short time without becoming " rancio." At the Experi- 
 ment Cellar of the Agricultural Department of the University of Cali- 
 fornia it has been shown that grapes can be heated gradually up to 48° C. 
 (118^° F.) for six hours without any special precautions to exclude the 
 air, and acquire no taste of caramel or rancio. In fact, wines made 
 from grapes heated in this way were remarkable for their clean taste, 
 freshness, and bouquet — qualities associated with cool fermentations. 
 
 The following table summarizes the main effects of high temperature 
 in the making of dry wine: 
 
 A. Direct effects : — 
 
 (a) Beneficial : 
 
 1. Increase of color. 
 
 2. Increase of tannin. 
 
 3. Increase of body. 
 
 (b) Injurious: 
 
 1. Oxidation. 
 
 2. Caramelization. 
 
 3. Loss of alcohol. 
 
 4. Loss of bouquet and freshness. 
 
 B. Indirect effects : — 
 (a) Beneficial: 
 
 1. Destruction of injurious ferments (sterilization) in the 
 unfermented must (artificial heating). 
 (6) Injurious: 
 
 1. Growth of injurious ferments in the fermenting must 
 
 (hot fermentation). 
 
 2. Abnormal excretions of the yeast. 
 
 In order to utilize our raw material to the utmost it is necessary to 
 devise a system of wine-making which will combine the beneficial effects 
 of heat in the extraction of color, tannin, and body with those of cool 
 
22 
 
 UNIVERSITY OF CALIFORNIA— EXPERIMENT STATION. 
 
 fermentation in producing bouquet, freshness, and maximum amount 
 of alcohol. This is what is done to a certain imperfect extent by the 
 Debono method. If the spontaneous heating of the pomace which occurs 
 in that method could be replaced by an artificial heating, the method 
 would be more nearly perfect and more under control. The experiments 
 of Rosenstiehl, Kiihn, Mathieu, and others in sterilization of musts for the 
 purpose of using pure and selected yeasts have shown that this can be 
 done. Their methods, however, are rendered unnecessarily trouble- 
 some and expensive by attempting to effect: (1) complete sterilization, 
 and (2) complete absence of air. The researches of Kayser and Barba 
 show that neither of these objects are necessary for the ordinary pur- 
 poses of wine-making, and their results have been fully corroborated by 
 tests made at the California Experiment Station at Berkeley. 
 
 Extraction of Color and Tannin by Heat. — In 1898 a series of experi- 
 ments was made at Berkeley to determine to what extent color and 
 tannin could be extracted before fermentation by direct heating of the 
 grapes. A summary of the results is shown in the following table: 
 
 TABLE I. Extraction of Color and Tannin from Fresh Grapes by Heat. 
 
 <i 
 
 
 —— 
 
 
 / 17 
 
 1. Witness. (Ordinary fermentation at 30° C.) 
 
 2. Heated to 50° C. in one hour 1.00 hour 
 
 (a) Kept at 50° C. for 30 minutes longer _ . 1.50 
 (6) Kept at 50° C. for 90 minutes longer ._ 2.50 
 
 3. Heated to 60° C. in 80 minutes '.. 1.30 
 
 (a) Kept at 60° for 60 minutes longer 2.30 
 
 (6) Kept at 60° C. for 120 minutes longer . 3.30 
 
 4. Heated to 70° C. in 90 minutes 1.50 
 
 (a) Kept at 70° C. for 45 minutes longer .. 2.25 
 (6) Kept at 70° C. for 90 minutes longer .. 3.00 
 
 5. Heated to 65° C. in 3 hours and 20 minutes, after 
 
 adding 10.5% alcohol t 
 
 Color. 
 
 Tint. 
 
 2 VR 
 
 5VR 
 
 3 VR 
 2 VR 
 
 VR 
 
 *VR+ 
 VR+ 
 
 VR+ 
 
 VR-j- 
 VR+ 
 
 VR 
 
 In- 
 tensity. 
 
 66.6 
 
 19.3 
 37.7 
 74.0 
 
 95.0 
 133.0 
 174.0 
 
 138.0 
 160.0 
 160.0 
 
 120.0 
 
 Tannin 
 
 .357 
 
 .108 
 .135 
 .217 
 
 .328 
 .385 
 .500 
 
 .246 
 .369 
 .450 
 
 .552 
 
 Acid. 
 
 .45 
 
 .38 
 .37 
 .30 
 
 .50 
 .45 
 .52 
 
 .48 
 .46 
 .46 
 
 .38 
 
 *The + indicates the color brighter than the first tint of the colorimeter, 
 t Corrected for dilution and contraction due to the addition of alcohol. 
 
 With regard to the extraction of color, an inspection of the intensity 
 shows that heating the grapes for two hours and a half at 50° C. (122° F.) 
 extracted more color than an ordinary fermentation at 30° C. (86° F!), 
 while heating them for about the same time at 60° C. (140° F.) or one 
 hour and a half at 70° C. (158° F.) extracted about twice as much. Still 
 longer heating extracted still more color, the maximum being about 
 three times that of the ordinary fermentation. It may be noted at 
 t be same time that the kind of color or tint was in all cases better than 
 that of the fermented wine, except where the heating had been insuf- 
 
MANUFACTURE OF DRY WINES IN HOT COUNTRIES. 
 
 23 
 
 ficient. Heating for one hour and a half at 50° C. was insufficient to 
 properly extract the color, either as regards tint or intensity. In all 
 the other cases the color was not only better than that of the fermented 
 wine, but extended beyond the limits of the scale toward the VR end, 
 showing that it was better than that of any wines ordinarily found in 
 France where the scale is adopted. 
 
 It has been objected that the color extracted by heat in this manner 
 is of a different nature from that extracted by fermentation, and that 
 most of it would be deposited by the alcohol formed during fermenta- 
 tion. The fifth experiment, at the bottom of the column, shows that, 
 while this may be partly true, yet with the addition of 10-£% of alcohol 
 before the heating, twice as much color was extracted in 3^ hours at 
 65° C. (149° F.) as by fermentation, and that the tint was better. 
 
 . In order to test whether this destruction or precipitation of color by 
 the alcohol continued on further contact, the tests summarized in the 
 following table were made. 
 
 A quantity of Lagrein grapes from Tulare was crushed and heated to 
 70° C. to extract the color. The must contained 27.4% of solid contents 
 by spindle and .47% of acid calculated as tartaric. The color of the 
 must at the commencement of the experiment (September 23, 1899) 
 was VR 85.3. The colored must was placed in ten bottles holding 
 125 c.c. each, and various amounts of alcohol added to each. Two 
 series were made, to one of which was added .4% of tartaric acid. The 
 bottles were filled quite full, well corked, and sterilized at 60° C, in 
 order to eliminate as much as possible the influence of oxygen and 
 fermentative organisms. 
 
 TABLE II. Effect of various amounts of Alcohol and Tartaric Acid on the Stability of the 
 Coloring Matter of Red Grapes. Color after 6| Months. 
 
 No Acid Added. 
 
 Tint. 
 
 In- 
 tensity.* 
 
 Acid Added. 
 
 Tint. 
 
 In- 
 tensity.* 
 
 1. Must + 0% of alcohol 
 
 2. Must-}- 5% of alcohol 
 
 3. Must + 10% of alcohol 
 
 4. Must -f- 15% of alcohol 
 
 5. Must 4-20% of alcohol 
 
 2 VR 
 
 2 VR 
 
 3 VR 
 
 3 VR 
 
 4 VR 
 
 57.9 
 53.2 
 39.6 
 41.1 
 41.2 
 
 VR 
 VR 
 VR 
 VR 
 VR 
 
 58.8 
 56.9 
 57.7 
 55.8 
 56.6 
 
 * These figures are corrected for the dilution and contraction due to the addition of alcohol. 
 
 No. 1 shows that the must to which no alcohol was added lost 32% of 
 its color in six months, and that this loss was not prevented by the 
 addition of a considerable quantity of tartaric acid. The must to which 
 was added 5% of alcohol lost 38% of its color, and that with 10% of 
 alcohol 46%. The addition of 15% and 20% of alcohol had no more 
 effect in destroying coloring matter than 10%, though there was a slight 
 degradation of tint. The last column shows that the addition of tar- 
 
24 UNIVERSITY OF CALIFORNIA— EXPERIMENT STATION. 
 
 taric acid was very effective in counteracting the effect of the alcohol 
 as the loss of color due to alcohol where tartaric acid was added aver- 
 aged only 34%, or very little more than that of the pure must. 
 
 That heating the grapes is equally effective in extracting the tannin 
 is well shown by Table I. The tests indicate that, with the grapes used, 
 sufficient tannin is extracted before the maximum color extraction is 
 reached. They also indicate that there is danger that too long or 
 too high heating may extract too much tannin, and that it may be 
 impossible to get the maximum color extraction without getting too 
 much tannin. However, test 4a shows that twice the color may be 
 obtained by heating to 70° C. (158° F.) for an hour and a half before 
 the tannin-content reaches that of an ordinary fermentation. With 
 further heating more tannin may be obtained, and the maximum was 
 not reached in any of the tests. Undoubtedly, prolonged heating would 
 dissolve some of the tannin in the seeds, so that the astringency could 
 probably be increased as much as desired, even with grapes normally 
 lacking in tannin. The presence of too much tannin is much less dan- 
 gerous than too little, as it increases the keeping qualities of the wine 
 and disappears gradually with age or can be removed to a great extent 
 by fining. Moreover, Professor Barba has shown that the tannin in the 
 must is very rapidly eliminated if the must is kept without fermentation.* 
 If, therefore, it is necessary to heat the grapes for a long time to extract 
 the color, the superfluous tannin can be diminished to any desired extent 
 by delaying the fermentation. 
 
 These laboratory experiments demonstrated the probability that 
 color and tannin could be extracted by heat, the red must separated 
 from the pomace and fermented in the same manner as white wine. If 
 this could be done without deterioration of quality from some unfore- 
 seen cause, a great advance would have been made in the certainty of 
 making good wine in hot localities. The cool fermentation of must 
 without the pomace is a comparatively simple operation. 
 
 While these laboratory tests were in progress, corresponding wine- 
 making tests were undertaken in the cellar to throw light on the feasi- 
 bility of the method in actual practice. 
 
 About three quarters of a ton of red grapes was obtained from the 
 Tulare Experiment Station. These grapes were grown in black, alkaline, 
 sandy soil in one of the hottest regions of the State, where all the con- 
 ditions which are supposed to render a hot region unsuitable for the 
 production of dry wine are at their worst. The grapes consisted of 
 Lagrein 75%, Malbec 14%, and Valdepenas 11%, and the mixture con- 
 tained 24.64% of fermentable sugar and .34% of acid calculated as tar- 
 
 * Barba, M., in "Annales de la SociSte* des Viticulteurs de France," vol. VI, p. 100: 
 
 Tannin in must of heated grapes immediately after heating _. .910 
 
 Tannin in wine of heated grapes fermented immediately after heating _ 820 
 
 Tannin in must of heated grapes one day after heating .720 
 
 Tannin in must of heated grapes four days after heating . .260 
 
MANUFACTURE OF DRY WINES IN HOT COUNTRIES. 
 
 25 
 
 taric. The grapes were therefore totally unfitted for the production of 
 dry red wine by the ordinary methods of wine-making. Grapes with 
 such high sugar-content and low acidity would fail to ferment dry, 
 not only in the San Joaquin Valley but in any part of California, and, 
 in nine cases out of ten, the tanks would almost certainly "stick" in 
 fermentation, and the wine spoil before it was three months old. No 
 grapes more suitable to detect any weak point in the method could have 
 been chosen. 
 
 One-fifth of the crushed and mixed grapes was fermented in the 
 ordinary way in an open fermenting vat. More than the usual care 
 was taken, the grapes being thoroughly stirred twice a day and the vat 
 kept covered. The fermentation was cool, never exceeding 79° F., and 
 the wine was nearly dry at the end of thirteen days. 
 
 Fig. 1. 
 
 Heating Vat. Cooling Vat. 
 
 Heating and Cooling Vats. Showing the plan adopted for heating the grapes and 
 cooling the must before fermentation. 
 
 The other four-fifths of the crushed grapes was placed in a small 
 fermenting-vat, which they about two-thirds filled. At the bottom of 
 this vat was a coil of half-inch block-tin tubing, through which a stream 
 of water of a temperature of 80° C. (176° F.) was run. The vat was 
 then covered with a canvas sheet, which was removed every half hour 
 and the heating grapes thoroughly stirred. The heating commenced at 
 10 a. m., the temperature of the grapes being 18.5° C. (65° F.), and 
 continued until 4 p. m., when the temperature of the grapes had risen 
 gradually to 48° C. (118° F.). The red must was then drawn off and 
 mixed with the must pressed from the heated pomace, and placed in an 
 open vat (see Fig. 1). 
 
 The color of the must, as it ran from the heater, was 1 VR — 78, and 
 of that which ran from the press VR — 102. The amount of tannin 
 
26 
 
 UNIVERSITY OF CALIFORNIA— EXPERIMENT STATION. 
 
 in the mixture was .262%. The must was cooled, immediately after 
 mixing, to 30° C. (86° F.) by means of a coil similar to the heating 
 coil, through which water at 20° C. (68° F.) was run. It was then 
 divided into four equal lots, numbered 2717a, 27176, 2717c, and 2717d, 
 each of which was placed in a separate keg. Nos. 27176 and 2717rf each 
 received an addition of tartaric acid. Fermentation was started by the 
 addition of yeast and was finished in all cases in twelve days, the tem- 
 perature being practically the same as that of the ordinary fermenta- 
 tion, never exceeding 26° C. (79° F.). As soon as the wines were dry 
 they were racked into clean casks, kept for a few days in the fermenting- 
 room at 21° C. (70° F.), and as soon as clear racked again and put in 
 the cool storage cellar. The wine fermented in the ordinary way 
 received the same treatment after fermentation. Some of the data 
 obtained are shown in the following table: 
 
 
 Must. 
 
 Wine. 
 
 
 Acid. 
 
 Acid. 
 
 Tannin. 
 
 Alcohol. Co ^ ts< 
 
 Time of 
 Fermen- 
 tation. 
 
 Color. 
 
 Witness: 2717 
 
 .34 
 .54 
 .60 
 .44 
 .53 
 
 .38 
 .41 
 .60 
 .47 
 .53 
 
 
 
 
 13 days 
 12 days 
 12 days 
 12 days 
 12 days 
 
 3 VR 30.7 
 
 f 2717a 
 
 Heated J 27176 
 
 grapes. 1 2717c 
 
 I 2717d- 
 
 .151 
 .153 
 .153 
 .139 
 
 14.25 
 14.10 
 13.90 
 14.10 
 
 3.15 
 2.81 
 3.15 
 2.60 
 
 2 VR 29.2 
 2VR 35.7 
 2 VR 25.0 
 2 VR 32.0 
 
 The four wines made from the heated grapes were bottled when they 
 were eighteen months old, and were in excellent condition. They 
 remained in the cellar four years, when they were opened and tasted. 
 They were all perfectly sound and clear. A thin, tightly adhering 
 deposit had been formed in the bottles, proving by its character the 
 perfect keeping-qualities of the wine. The wines were fresh, clean tast- 
 ing, and of good color. The bouquet was remarkably strong, proving 
 conclusively that heating the grapes to 48° C. does not diminish this 
 quality in the wine, and even tending to show that, on the contrary, it 
 increases it. 
 
 This series of tests has clearly demonstrated a fact of great impor- 
 tance to wine-makers of the interior valleys, viz: that grapes grown in 
 rich, sub-irrigated soil in the hottest part of the valley can, if properly 
 handled, be used for the production of not only a sound dry red wine, 
 but of a wine of exceptional quality, superior in every respect to the 
 bulk of the wines produced in any part of California or of Europe. 
 Whether fine wines, equal to the best of the Medoc and Burgundy or of 
 the coast valleys of California, can be produced there is a matter of 
 much less importance at present, and can be left for the future to 
 decide. 
 
MANUFACTURE OF DRY WINES IN HOT COUNTRIES. 27 
 
 ADDITION OF SUBSTANCES DEFICIENT IN THE GRAPES. 
 
 Water. — One of the most frequent causes of difficult fermentation and 
 spoiled wine, when the attempt is made to make dry wine in a hot cli- 
 mate, is extreme sweetness of the grapes. Under the most favorable 
 conditions it is impossible to cause the transformation into alcohol of 
 more than about 28% of sugar in the must, and this only after a very long 
 time. Under ordinarily favorable conditions it is impracticable to fer- 
 ment out more than 25%, producing 14.5% of alcohol. Under the condi- 
 tions existing in an ordinary cellar in a warm locality the limit is much 
 lower, and may be taken as somewhere about 22% of actual fermentable 
 sugar, corresponding to between 22.5% and 23% on Balling's saccharom- 
 eter, and capable of yielding a wine containing 13% of alcohol. Even 
 with this amount of sugar, most of the fermenting vats will " stick " 
 with 2% to 4% of unfermented sugar in warm seasons with ordinary 
 methods of wine-making. Grapes containing only 19% of fermentable 
 sugar can, however, be nearly always fermented dry with the ordinary 
 methods, except in very hot seasons or where very large fermenting- 
 vats are employed. 
 
 As about three quarters of the weight of ripe grapes consists of water, 
 the addition of a little more when there is too much sugar naturally 
 suggests itself. The procedure has been and is still frequently used, 
 but often with but indifferent success. The reasons for failure are two: 
 Firstly, the dilution of the sugar entails at the same time the dilution 
 of the other constituents of the must, notably the acid; and secondly, 
 impure water is often used, water containing large amounts of salts or 
 of organic matter, wdiich materially alters the flavor of the wine and 
 the character of the fermentation. The dilution of the acid is the most 
 serious defect, and is the more serious the riper the grapes, for the more 
 sugar there is present usually the less there is of acid. For example: 
 if we dilute a must containing 24 grams of sugar in 100 c.c. (about 24.4% ? 
 Balling) and .4% of acid to 22^ (23.2%, Balling), by adding 7% of 
 water we also reduce the acid, which is already too low, to .37%. 
 Wherever dilution is practiced, therefore, it is almost always necessary 
 to supplement the acidity. Moreover, the practice can be used success- 
 fully only where the grapes are naturally high in extract and coloring 
 matter. In other cases the wine will be thin and flat. There is a well- 
 founded prejudice against adding water to wine either before fermentation 
 or after. This has its origin, to a great extent, in the fact that in 
 Europe the addition of water is done for purposes of fraud, with the 
 simple object of making more gallons of wine out of a given quantity of 
 grapes. The addition of water to the wine after the fermentation is 
 never admissible under any circumstances, as it can never improve the 
 quality in any way, and will, in fact, always injure it. There are, how- 
 ever, cases where it is possible, by a limited amount of dilution before 
 
28 UNIVERSITY OF CALIFORNIA — EXPERIMENT STATION. 
 
 fermentation, to produce a good, sound, dry wine, where it would be very 
 difficult to do so without. This applies particularly to California, where 
 the richness of the grapes in all constituents except acid is often so 
 great that even after the addition of a certain amount of water to the 
 must the resulting wine has a higher degree of alcohol and extract than 
 the bulk of European wines, and could not be recognized as watered by 
 any "alcohol and acid" or other chemical or organoleptic test. How- 
 ever, the practice is to be commended only under exceptional circum- 
 stances, as there are almost always better ways of attaining the object — 
 a thorough, clean fermentation. 
 
 Tartaric Acid. — This acid is found in larger or smaller amounts in all 
 grapes and in all wines. Some of the acid exists " free " (that is, uncom- 
 bined with any base), but most of it occurs in combination with potash and 
 lime. The principal acidity of most grapes and wines is due to the 
 acid salt of potash and tartaric acid, bitartrate of potash, more com- 
 monly known as cream of tartar. Malic acid and its salts also occur 
 in considerable amounts, and some other acids in very small amounts. 
 Thus the acidity of a must is due to a number of acids and acid salts, 
 which vary somewhat in their proportions as well as in their total 
 amounts in various grapes and at various stages of ripeness. In unripe 
 grapes the free acids predominate; in ripe, the acid salts. 
 
 The importance of the acidity of the grapes in wine-making is so 
 great that no wine-maker should be without the means of determining 
 its amount. It is not necessary to know the exact amount of each con- 
 stituent of the acidity, and to determine it would be difficult and imprac- 
 ticable in wine-making; but some measure of the "total acidity," which 
 will give us an idea of its effect on the fermentation and on the quality 
 of the wine, is both useful and necessary. This may be found in vari- 
 ous ways, but the results are always given as sulfuric or tartaric acid. 
 That is, when we say a must has .8% acid as tartaric, we mean that its 
 acidity has the same effect on the reagents used in determining it as 
 .8% of pure tartaric acid would have. This does not give us the exact 
 amount of tartaric or of any of the acids in the must, but as the vari- 
 ous acid constituents occur in about the same relative proportions in 
 all grapes that are not very unripe, it gives us a convenient way of 
 comparing different grapes and of judging whether their acidity is suf- 
 ficient for our purpose. 
 
 The acidity affects the quality of the wine both directly and by its 
 effect on the fermentation. A dry wine requires a certain amount of 
 acidity or it will taste flat — a red wine with insufficient acidity drops 
 its color very rapidly. Its most marked effect, however, is due to its 
 influence on the fermentative organisms in the must. Yeast will mul- 
 tiply and grow in presence of a larger amount of acid than any of the 
 ordinary disease germs and bacteria occurring in must and wine. For 
 
MANUFACTURE OF DRY WINES IN HOT COUNTRIES. 29 
 
 this reason a very acid must nearly always undergoes a clean and 
 thorough fermentation, and the resulting wine clears rapidly and keeps 
 well. 
 
 It is impossible to say what the most desirable degree of acidity is, 
 as this varies with so many conditions. Red wine requires more than 
 white, as the former loses much in fermenting. Coloring grapes, such 
 as the Bouschets, require more than ordinary red grapes, as the 
 coloring matter is less stable. American grapes, such as Lenoir, require 
 still more, as they are liable to a peculiar change when lacking in acid, 
 which destroys their color. Moldy, unripe or otherwise defective grapes 
 require more than good grapes, on account of the large numbers of 
 bacteria and molds they contain. 
 
 According to Bouffard,* the average acidity of good red wines in the 
 south of France is .6% to .9%. Good wines may have less than this, 
 but they are then difficult to handle. As some of the acidity is lost in 
 fermentation, the must should have more than this. Roos f gives as 
 the most favorable acidity for red wine grapes in the south of France, 
 the following: 
 
 For Aramon, Carignane, and most red grapes 0.8% 
 
 For Bouschets 1.0% 
 
 For Jacquez( Lenoir) 1.2% 
 
 The acidity of ripe California grapes very rarely reaches these figures, 
 especially in the hotter parts, and this lack greatly intensifies the un- 
 favorable effect of hot fermentation. Even in the south of France the 
 grapes very commonly fall below these figures when allowed to mature 
 completely. There, the difficulty is usually overcome by gathering the 
 grapes under-ripe, to the detriment, as already observed, of both quality 
 and quantity. In large vineyards, however, it is often impossible to 
 gather all the grapes before they are thoroughly ripe, so the augmenta- 
 tion of the acidity by addition of acid to the grapes or wine is becoming 
 a common practice both there and in Algeria. The addition of the acid 
 to the wine after fermentation is practiced only when its object is to 
 increase the acidity for the taste of certain French markets, or to increase 
 the stability of the coloring matter in wine from color-grapes. Jacquez 
 wine is sometimes dosed with tartaric acid to the extent of 2%, which 
 makes it quite undrinkable but useful to blend with wines lacking in 
 both acid and color. Tartaric acid added to the wine after fermenta- 
 tion gives a harshness to the wine which is absent when the acid is 
 added to the must before fermentation. The only object of adding it 
 after instead of before is that a certain proportion is precipitated, and 
 this in the latter case is lost in the pomace or thick lees, while in the 
 former it is recovered in the argol deposited in the casks. 
 
 * " Revue de Viticulture," vol. 10, p. 545. 
 
 t Roos: "L' Industrie Vinicole Meridionale." Montpellier, 1898. 
 
30 UNIVERSITY OF CALIFORNIA— EXPERIMENT STATION. 
 
 For the purpose of regulating the fermentation, however, it must be 
 added to the crushed grapes, and in this case, unless used in extrava- 
 gant quantities, it has absolutely no ill effects on the flavor of the wine. 
 How much it is necessary or safe to use can be determined only by 
 experiment in each vineyard with each variety of grape. In a general 
 way, it may be said that experience has shown that with grapes very 
 low in acidity it is neither safe nor necessary to add enough acid to 
 bring up the amount to the figures given by Roos as normal. For 
 example, if a must shows .4% of acidity it is usually sufficient to add 
 enough tartaric acid to bring this acidity up to .6%, that is 4 pounds to 
 the ton of grapes. Some writers say it is rarely desirable to exceed 2 
 pounds to the ton,* while others believe it is quite admissible to go as 
 high as 5, 6, or even 8 pounds per ton.f In general, the best modern 
 practice seems to be not to exceed 4 pounds per ton, J and this in all 
 cases is sufficient to insure a good fermentation so far as acidity alone 
 can do this. The reason of this is that the addition of a certain amount 
 of tartaric acid to the must has a much stronger effect on regulating the 
 fermentation than an equivalent amount of natural acidity, because it 
 increases the "free" acid and diminishes the ''combined acid" or cream 
 of tartar. The former has a much more deterrent effect on bad ferments 
 than the latter, but when in great excess it also has an unpleasant 
 harshness to the palate. When we add tartaric acid to a must or wine 
 we get an increase of free tartaric acid in the liquid, but at the same 
 time we get a diminution of cream of tartar. The chemical reactions 
 to which this is due are obscure and complicated, but it is partly due to 
 the fact that the more free tartaric acid there is present the less capable 
 the wine is of keeping bitartrate of potash in solution. The addition of 
 tartaric acid always causes, therefore, a deposit of cream of tartar, and 
 therefore the increase in the acidity of the resulting wine is less than 
 corresponds to the amount of acid added. In a general way we may 
 say that we usually find in the wine about two-thirds of the acid added 
 to the must. The amount will vary, however, according to conditions. 
 If added directly to the wine we may increase the acidity by 70% of the 
 acid used.* If added to the must only 47% may be found in the wine,§ 
 while if added to the crushed grapes as little as 25% § may remain. 
 
 There is very little danger of making the wine harsh unless the maxi- 
 mum doses recommended are very much exceeded; and a slight harsh- 
 ness due to good acidity diminishes with age. 
 
 Citric Acid. — This acid has been used extensively during recent 
 years to cure or prevent a certain form of the disease of wines which 
 the French call "la casse." Its efficacy in this respect, and the com- 
 
 * Bouffard, A. : " Revue de Viticulture," vol. 10, p. 546. 
 
 tSebastian, V: "Le Sucrage des Vins," p. 46. Montpellier, 1903. 
 
 JPacottet: "Vinification," p. 33. Paris, 1904. 
 
 §FonHecaand Chiaramonte, quoted by Pacottet, P.: "Vinification," i>. 74. 
 
MANUFACTURE OF DRY WINES IN HOT COUNTRIES. 31 
 
 plete absence of any injurious effect on the wines treated, suggested its 
 use in the acidification of deficient must, before fermentation, in place 
 of tartaric acid. For this purpose it has been found equally efficacious 
 and, from most points of view, superior to tartaric acid. The only objec- 
 tion to its use is the doubt as to the presence of citric acid as a normal 
 constituent of grapes. Some investigators claim that it does exist natu- 
 rally in grapes in minute quantities, and as only minute quantities are 
 needed, and as the acid is as "innocuous and wholesome as tartaric 
 acid," there seems to be no reasonable objection to its use. It is 
 not and can not be used in any way to increase the quantity of wine 
 made from a given quantity of grapes, but only to improve its quality. 
 Its use can not therefore be considered a sophistication any more than 
 that of sulfurous acid or finings. 
 
 Citric acid has several advantages over tartaric. It does not give 
 the harshness to the wine which some tasters find in case of large addi- 
 tions of tartaric. It does not cause precipitation of the cream of tartar, 
 but on the contrary makes this latter slightly more soluble. This, together 
 with the fact that it seems to have a slightly more deterrent effect on 
 bacteria than tartaric, makes it possible to get the same effect with a 
 much smaller amount. From one half to one third the amount is used. 
 That is, for example, where it would be necessary to add 6 pounds of 
 tartaric acid to a ton of grapes, from 2 to 3 pounds of citric acid would 
 be equally effective. 
 
 It is essential that the citric acid should be pure. Citric acid is 
 sometimes found on the market, marked for dyer's uses, which is adul- 
 terated with oxalic acid. This would be extremely injurious to the 
 wine. There is, however, no difficulty now in getting pure citric acid 
 in quantities at about 30 cents per pound, which is very little more 
 than the cost of tartaric, and which, considering the smaller amounts 
 needed, makes it more economical than the latter. Citric acid of suit- 
 able quality is now made in quantity in California from refuse and cull 
 lemons. 
 
 Citric acid must not be confused with lemon oil or essence obtained 
 from the skins of lemons and used for flavoring. Pure citric acid has 
 a completely clean, simple, acid taste, without any lemon flavor what- 
 ever. 
 
 Plaster. — One of the oldest and most widespread methods of aiding 
 the fermentation by increasing the acidity of the must is by the addi- 
 tion of ordinary plaster of Paris or sulfate of lime to the grapes. The 
 plaster is sifted on to the grapes, as they come from the crusher, at the 
 rate of between 4 and 8 pounds to the ton. The practice was formerly 
 almost universal in southern France and similar climates, but it has 
 been greatly restricted by a law passed in 1891, limiting the amount of 
 sulfate of potash in wines to 2 grams per liter. 
 
32 UNIVERSITY OF CALIFORNIA— EXPERIMENT STATION. 
 
 The effect of the plaster is to cause a better fermentation and to increase 
 the keeping quality of the wine. It aids in the rapid clearing of the 
 wine and increases and brightens the color. The chemical action is 
 somewhat complex, but the final result is an increase in the acidity of 
 the wine and of the sulfate of potash. The lime sulfate acts on the 
 potash salts existing naturally in the wine, forming insoluble lime 
 tartrates, which are deposited, and soluble sulfates and acid sulfates, 
 which remain in the wine. The acid sulfates finally take the pot- 
 ash from the organic salts and become neutral sulfates of potash, 
 setting free the organic acids to increase the acidity of the wine. When 
 plaster of good quality is used it is a very cheap, effective, and easily- 
 applied means of assisting the fermentation, and is greatly in favor 
 among the wine-makers of nearly all warm regions. While very help- 
 ful in obtaining a sound, clear wine of good keeping qualities, it gives 
 a certain harshness which is inadmissible for fine wines. Many sam- 
 ples of plaster, moreover, contain carbonates, which make its use very 
 unreliable, and if present in any considerable quantities neutralize 
 more of the natural acidity of the wine than is set free by the sulfate. 
 
 The question of the harmful effects, on health, of wine containing 
 sulfate of potash is still in dispute. The law in France, however, lim- 
 iting the amount that a commercial wine may contain to 2 grams per 
 liter, makes impossible the use of enough plaster to have the desired 
 effect on the fermentation. For this reason its use is much more 
 restricted than formerly. Some wine-makers use it in conjunction with 
 tartaric acid, using as much plaster as possible without exceeding the 
 legal limit of sulfate in the wine, and making up the deficiency with 
 tartaric acid. 
 
 Phosphates. — Latterly many wine-makers in Algeria have been using 
 bi-basic phosphate of lime in the same way as plaster. It is sifted on to 
 the crushed grapes in the same way and produces very much the same 
 effect. It is superior to plaster, as it does not give the harshness due 
 to the latter, and does not increase the sulfates. Acid phosphates of 
 potash are left in the wine and the lime is deposited as neutral lime 
 tartrate. Nothing injurious is left in the wine, and the phosphates 
 doubtless aid the completion of the fermentation. It has, however, the 
 same defect of being unreliable, as its action is very variable and it is 
 impossible to foretell the effect of a certain dose. 
 
MANUFACTURE OF DRY WINES IN HOT COUNTRIES. 33 
 
 CONTROL OF FERMENTATION. 
 MODIFYING THE TEMPERATURE. 
 
 All the fermentations, good and bad, to which must or wine is liable 
 are caused by micro-organisms which get into the liquid either from the 
 outside of the grapes or from the crushers, casks, etc., with which the 
 liquid comes in contact. These micro-organisms, which thus get into 
 the must, consist of yeasts, molds, and bacteria of a very great number 
 of kinds. Few of these kinds, however, can grow in the must, and under 
 the best conditions of wine-making practically none grow but the true 
 wine-yeast. A perfectly clean or pure fermentation is one in which no 
 micro-organism takes part except the true wine-yeast. This is the ideal 
 condition toward which the wine-maker's efforts should tend. It is, 
 however, by no means essential for the production of good wine that 
 this condition should be reached. All that is necessary is that the true 
 wine-yeast should vastly outnumber all the others, and that nothing 
 should interfere with its healthy and complete action. In the finest 
 chateau wines, molds and false yeasts occur in the first stages of fer- 
 mentation, but the conditions of wine-making are such that they have 
 little or no perceptible effect on the must before the true wine-yeast 
 commences its action. This action soon overcomes all others and, if 
 nothing interferes with it, the wine is given a stability which makes it 
 a simple matter to prevent all ulterior action of injurious fermentative 
 agents. 
 
 The main problem of wine-making, then, after we have obtained the 
 best possible raw material, is to produce a clean fermentation. This is 
 to be accomplished in one or both of two ways: (a) by establishing con- 
 ditions favorable to the growth of wine-yeast and unfavorable to the 
 growth of the other organisms; and (b) by eliminating the other organ- 
 isms and having as little present as possible in the must but pure wine- 
 yeast. One of the most essential conditions is established when our 
 raw material is of proper composition, that is, when the various sub- 
 stances in the grapes, especially the acid and sugar, are in the proper 
 proportion. This is all that is necessary in a cool climate to insure a 
 clean fermentation if the presence of too many unfavorable fermentative 
 organisms is prevented by ordinary care and cleanliness. In a hot 
 region, on the other hand, however favorable the composition of the 
 grapes and however cleanly the methods of handling them, a thorough, 
 clean fermentation is rarely obtained unless we control other condi- 
 tions. The principal of these conditions is the temperature. The use 
 and necessity of a high temperature to properly extract the grapes have 
 already been pointed out. The danger of high temperatures consists 
 principally, in practice, in their effect on the fermentative organisms. 
 
 The injurious effects of too much heat during fermentation are of two 
 
 3— bul. 167 
 
34 UNIVERSITY OF CALIFORNIA— EXPERIMENT STATION. 
 
 kinds, which should be carefully distinguished. In the first place, high 
 temperatures encourage the growth of the bacteria which cause most of 
 the spoiling of wine. In the second place, the chemical actions which 
 the yeast brings about in the must at a high temperature are different 
 from those which it causes at a low temperature. The first effects 
 would be prevented by any means which excluded the presence of bac- 
 teria in the fermenting must; the latter are dependent only on the 
 yeast. It is possible to ferment completely all the sugar in any ster- 
 ilized must which does not contain more than 26% at any temperature 
 between 15 c C. (59° F.) and 35° C. (95° F.); but the qualities of the wine 
 made at the two temperatures will be very different. Leaving out of 
 account the extractive effects, a wine fermented near the lower limit 
 will be smoother, fresher, and contain more alcohol and bouquet than 
 one fermented near the higher. In practice, a wine fermented at the 
 higher temperature may be more valuable on account of the greater 
 color, tannin, and body it contains, if these latter characteristics are 
 what constitute its main value. 
 
 It is the failure to properly distinguish between these two effects of 
 heat that causes the wide discrepancies between the figures given by 
 various authorities as to the most favorable temperature for wine- 
 making. The finest Rhine wines are kept at about 15° C. (59°F.) during 
 the greater part of the fermentation, while in Algeria it is considered, 
 by most wine-makers, advisable to allow the temperature to rise to 
 35° C. (95° F.). In the former case the most valuable characteristic of 
 the wine is its bouquet and aroma, which would be destroyed at high 
 temperatures, while in the latter the color, body, and tannin, which 
 constitute the main value of the wine, would not be sufficiently extracted 
 from the skins at a lower temperature. In the Medoc and Burgundy 
 districts it is considered desirable to keep the wine during fermentation 
 at between 25° and 30° C. (77° and 86° F.). This is low enough not to 
 destroy either the freshness or the bouquet, and high enough to extract 
 the skins sufficiently with the thorough stirring and long maceration 
 practiced in these regions. 
 
 In hot regions, like those of Algeria, and most parts of California, all 
 considerations give way to the necessity of finding means of making 
 a sound wine, which is the first essential. For this purpose the temper- 
 ature will in these regions nearly always rise too high unless means 
 are taken to prevent it. 
 
 COOLING DEVICES ( PHYSICAL) . 
 
 The temperature to which the fermenting grapes rise is determined by 
 the heat they contain when crushed, plus the heat generated by fermen- 
 tation and minus that lost during the process by radiation and conduc- 
 tion. The warmer the grapes and tin; more sugar they contain, therefore, 
 
MANUFACTURE OF DRY WINES IN HOT COUNTRIES. 35 
 
 the higher the temperature will rise. The smaller the fermenting mass, 
 the cooler the air, the greater the conductivity of the vats, and the 
 slower the fermentation, the less the temperature will rise. Gathering 
 the grapes only in the early morning, or leaving those gathered in the 
 hot part of the day exposed to the night air before crushing, is a very 
 effective way of controlling the temperature in small cellars. In large 
 cellars this is impossible, owing not only to the practical difficulties of 
 finding receptacles for the grapes, but to the fact that however cold the 
 grapes are crushed, the temperature of large masses will rise above the 
 danger point unless the heat of fermentation is eliminated in some 
 way. Professor Bouffard* has shown experimentally that 180 grams of 
 sugar give out at least 23.5 calories during fermentation. This means 
 that 22% of sugar in a fermenting must is capable of generating enough 
 heat to raise the temperature about 90° F. If none of the heat were 
 lost, therefore, a must containing 22% of sugar and commencing fer- 
 mentation at a temperature of 60° F. would reach 100° F. and " stick " 
 while it still contained 12% of sugar. In practice some of this heat is 
 always lost, but with hot weather and large vats it shows that it is 
 possible for the fermenting must to " stick" however low in sugar-con- 
 tents it may be, and however cool the grapes are when crushed. Cool- 
 ing the grapes or must, therefore, is only a partial remedy, and quite 
 insufficient to insure thorough fermentation unless supplemented by 
 some other means. 
 
 Aids to Radiation. — Any means which promotes the radiation of heat 
 from the fermenting mass tends to moderate the rise in temperature. 
 One such means is the use of small fermenting vats. The smaller the vat 
 the greater will be the surface from which heat radiates in proportion 
 to the volume of the mass of grapes. For example, a fermenting vat of 
 the ordinary form, containing 100 gallons, will have a radiating surface, 
 reckoning the top, bottom, and sides, of about 31 square feet, or .311 
 square foot for every gallon of crushed grapes it contains, while one of 
 1,000 gallons will have about 144 square feet, or .145 square foot per 
 gallon, and one of 10,000 gallons about 670 square feet, or only .067 
 square foot for every gallon. How little the radiation from even the 
 smallest vats used in commercial cellars can be depended on to keep 
 the temperature below the danger point is familiar to every practical 
 wine-maker. Numerous experiments made at Berkeley make this point 
 certain. f To quote one: Two hundred pounds (about 25 gallons) of 
 crushed grapes were placed in a small vat and allowed to ferment in 
 the ordinary way with three stirrings daily. The temperature of the 
 room varied between 72° and 75° F., and the grapes showed 63° F. when 
 
 * " Progres Agricole et Viticole," vol. 24, p. 345. 
 
 t E. W. Hilgard: "Methods of Fermentation," p. 15. See exp. 792, Report of Agri- 
 cultural Experiment Station, Berkeley, 1888. 
 
36 UNIVERSITY OF CALIFORNIA— EXPERIMENT STATION. 
 
 crushed. Notwithstanding these favorable conditions of cool grapes and 
 small vat, the temperature rose to 94° F. during fermentation. The 
 grapes contained about 24% of sugar, which, according to Bouffard's 
 tests, would produce enough heat in fermenting to raise the grapes from 
 their initial temperature of 63° F. to about 120° F. Radiation thus got 
 rid of 24° F. by the time the fermentation reached its maximum. In a 
 10,000-gallon vat radiation could have removed, providing all other 
 conditions were the same, only one-seventh of this amount, and even in 
 a 1,000-gallon vat only three-tenths, which would not have been enough 
 to prevent arrest of fermentation long before the sugar was all gone. 
 
 Vats smaller than 1,000 gallons are not practicable, even in small 
 cellars, so that control of temperature by diminishing the size of the 
 vats is incomplete and impracticable for California conditions. The 
 same may be said of vats of special forms. Very high, narrow vats 
 such as are used by brewers, or very wide, shallow vats as used in some 
 wineries, radiate more heat than vats of the ordinary form: but the 
 difference is so little under ordinary conditions that it can not be 
 depended upon to prevent " sticking." A 3,000-gallon vat with a depth 
 of 6 feet presents a radiating surface of about 313 square feet, while one 
 of the same capacity with a depth of only 3 feet has 388 feet of radiating 
 surface. The difference in radiated heat is no doubt greater than is 
 indicated by these figures, as most of the radiation takes place from the 
 upper surface of the pomace, which in the shallow vat will have an area 
 of about 125 square feet, and in the deep vat only about 55 square feet. 
 The difference is not enough, however, to keep the temperature - suffi- 
 ciently low, except in small vats and in cool weather. 
 
 Various forms of gratings for submerging or dividing the pomace have 
 been in limited use as aids to cool fermentation. They are attempts to 
 counteract the tendency of the pomace to rise to the top and form a 
 semi-dry "cap" where the heat becomes excessive, even when the must 
 below keeps comparatively cool. Some of these gratings keep the pomace 
 near the bottom of the vat, where it can not become hotter than the 
 must above, owing to the tendency of the cooler must to sink on account 
 of its greater specific gravity. Others are arranged with the object of 
 promoting the continual circulation of the must through the cap, and 
 thus preventing any part becoming hotter than the rest. These appli- 
 ances are all very troublesome to use, and at the best are only palliatives. 
 Frequent stirring (foulage) of the fermenting mass is almost equally 
 effective and is more easily applied. 
 
 An ingenious method of cooling, at one time discussed a good deal and 
 tested to some extent in Algeria, is that of Toutee. It is based on an 
 attempt to increase; the heat radiation from the sides of the vats. With 
 the ordinary wooden vat and still more with stone or concrete vats, 
 there is very little radiation, except from the top of the grapes exposed 
 
MANUFACTURE OP DRY WINES IN HOT COUNTRIES. 37 
 
 to the air. Toutee constructed vats of metal, where the radiation from 
 the sides was so much increased that, except in warm weather, white 
 must was kept sufficiently cool in 3,000-gallon vats. With red grapes, 
 owing to the presence of the pomace, the effect was less, unless continued 
 stirring or pumping-over was practiced. A vital defect of the system 
 was its cost and the necessity of replacing the vats on hand. 
 
 "Pumping-over" is an operation resorted to very frequently in Algeria 
 and France as in California for promoting a dilatory fermentation. Its 
 rationale is not always, however, well understood. It is not properly a 
 method of cooling. In fact, it generally has the other effect. The only 
 case in which it really cools the must is near the end of the fermenta- 
 tion, when it is desirable to prevent cooling in order not to check the 
 action of the yeast. It is often, nevertheless, very effective in producing 
 a thorough fermentation. This it does, not by cooling the must, but by 
 providing the yeast with an abundance of oxygen, which strengthens 
 and stimulates it and enables it to attack the sugar more forcibly. It 
 is very effective and useful at the beginning of the fermentation in cool 
 weather, or when real cooling means are applied as well. In hot weather 
 it is more likely to increase the trouble, and toward the end of fermenta- 
 tion it entails a loss of alcohol and a vapid taste, which may more than 
 offset any benefit derived. 
 
 Attemperators and Refrigerators. — The failure, in the majority of cases, 
 of all the methods previously discussed, long ago led the wine-makers 
 of Algeria to look for some more effective and reliable method of con- 
 trolling the temperature. This they have found, after many trials, in 
 two or three forms of machines known by the above names. An attem- 
 perator is an appliance — usually a long spiral tube — which is placed 
 in the fermenting-vat and through which water or other cooling liquid 
 is run. A refrigerator is an appliance — also usually a spiral tube — 
 outside the vat, through which the wine is run, and which is cooled by 
 a cold liquid on the outside. Innumerable forms of both classes of 
 machines have been tested, but only a few have come into general use. 
 
 A very efficient form of attemperator is that used at the Government 
 wine cellar of Constantia in Cape Colony and in some Australian 
 cellars. 
 
 Fig. 2 will make clear the principles involved. Each vat is fur- 
 nished with a grating by which the pomace is kept submerged several 
 inches below the must, and with a small pump for bringing the must 
 from the bottom to the top. When the temperature rises to the point 
 which it is not desired to exceed, a copper coil is placed in the must 
 above the grating and attached to a water tap. Cool water running 
 through this coil soon brings down the temperature of the supernatant 
 must. In the meanwhile the pump, which is attached to a shaft which 
 4— bul. 167 
 
38 
 
 UNIVERSITY OF CALIFORNIA— EXPERIMENT STATION. 
 
 works all the small vat pumps, is started, and a continuous but slow- 
 flow of liquid is established, which is cooled as it comes in contact with 
 the coil on top and cools the pomace as it passes through. This 
 arrangement gives very perfect control of the fermentation, with compara- 
 tively little labor. In vats of one or two thousand gallons the tempera- 
 ture can be kept at any point desired, and the extraction of the pomace 
 can be increased or diminished very considerably by the more or less 
 constant working of the vat pumps. Whether the control of tempera- 
 ture or the extraction of the pomace would be as complete in large vats 
 where the pomace cap beneath the grating was very thick, is doubtful. 
 
 Fig. 2. Cooling device for fermenting-vat. 
 
 The method, however, is excellent in small or medium-sized cellars, 
 where the object is to make wine of high quality. Its principal objec- 
 tion is the initial expense. 
 
 Cheaper attemperators have been made consisting simply of coils of 
 copper or varnished galvanized iron piping placed around the inside 
 walls or in various other positions in the vats. They are all efficient 
 enough for the cooling of white wine where there is no solid matter 
 present, but are quite inadequate for the case of red wine, and fail almost 
 completely to prevent undue heating in the cap, except in small vats 
 where continuous stirring can be practiced. 
 
MANUFACTURE OF DRY WINES IN HOT COUNTRIES. 
 
 39 
 
 Refrigerators. — Appliances of many forms arranged for the cooling of 
 the fermenting must outside the vat have been devised and tested. 
 Only two types are in extensive use at the present time, however. The 
 more common of these is that originated by Muntz and Rousseau,* 
 which is made by several manufacturers of cellar appliances. It con- 
 sists of a series of horizontal, superposed copper tubes, connected in 
 such a way that the warm must enters at the bottom and emerges at the 
 top. The cooling is obtained by causing water to drop or flow over the 
 tubes from top to bottom. This form (Fig. 3) is useful especially where 
 water is scarce, and is the type used almost exclusively in Algeria. 
 There is probably not a single large cellar in Algeria, Oran, or Constan- 
 
 ts*"' 
 
 Fig. 3. Algerian type of refrigerator. 
 
 tine which does not possess one or more of these machines, and by their 
 use the production of a sound, completely fermented wine has become 
 possible in all cases. 
 
 The amount of cooling necessary is indicated by the following example: 
 
 Grapes containing 20% of Fermentable Sugar. 
 
 Temperature of grapes when crushed 20° C. 
 
 fHeat liberated by fermentation of 20% of sugar 26° C. 
 
 Total temperature units 46° C. 
 
 In order, then, to prevent the temperature of the fermenting must from 
 rising above 35° C, it is necessary to remove 11° C, or approximately 
 11 calories. That is to say, when the temperature reaches 35° C, if it is 
 
 * See Bull. 117, Calif. Agr. Exp. Station. 
 
 t Calculated by using Prof. Bouffard's figure of 1.3 calories for each per cent of sugar. 
 
40 
 
 UNIVERSITY OF CALIFORNIA— EXPERIMENT STATION. 
 
 cooled to 24° C. the sugar will have all disappeared by the time it 
 reaches 35° C. again, as shown by the following table: 
 
 
 Temperature. 
 
 Degrees of Temperature. 
 
 Per Cent of Sugar. 
 
 
 Gained. 
 
 Removed. 
 
 Removed. 
 
 Remaining. 
 
 20° - 
 
 
 
 
 20.0 
 
 35° ~ 
 
 15 
 
 
 11.5 
 
 8 5 
 
 24° cooled..- - . 
 
 11 
 
 
 35° 
 
 11 
 
 20.0 
 
 00 
 
 
 
 
 This supposes that no heat is abstracted except that taken by the 
 cooling machine. In practice, even in large concrete vats, a certain 
 amount of heat is lost by radiation, so in the case above it would not 
 be necessary to remove quite 11 calories. In California, with our sweeter 
 grapes and hotter weather, it would be necessary to remove more heat 
 than in Algeria and generally to cool twice. The following may be 
 considered an average example: 
 
 Grapes containing 22 % of Fermentable Sugar. 
 
 Temperature of grapes when crushed . 70.0° F. 
 
 Heat liberated by 22% of sugar r 51.7° F. 
 
 Total temperature units 121.7° F. 
 
 In order to prevent the temperature rising above 95° F. it would be 
 necessary to remove heat equivalent to 26.7° F. or, allowing for a certain 
 amount of loss by radiation and conduction, the cooler would have to 
 remove about 20° F. It would be easier and probably more desirable 
 to remove this by two coolings of 10° F. each than by a single one of 
 20° F.; easier, because it requires less time and less water of a given 
 temperature to cool must from 95° to 85° than from 85° to 75°, and 
 probably more desirable, as some observers claim that too much cooling 
 at one time delays fermentation. The relation of the temperature with 
 the disappearance of the sugar would then be somewhat as follows: 
 
 
 Degrees of Temperature. 
 
 Per Cent of Sugar. 
 
 Temperature of Wine. 
 
 Gained. 
 
 Removed. 
 
 Removed. 
 
 Remaining. 
 
 70° 
 
 
 25 
 
 
 ........ 
 
 
 12 
 
 22 
 
 95° 
 
 10 
 
 85° (first cooling) . - 
 
 
 <)5° . . 
 
 10 
 
 17 
 
 5 
 
 85° (second cooling) 
 
 
 10 
 
 
 05° 
 
 10 
 
 22 
 
 
 
 
 
 
 These figures in the temperature columns of the foregoing tables must 
 not be understood to represent the actual temperatures found in prac- 
 tice. At no time would there be a fall of temperature from 95° to 85° F. 
 
MANUFACTURE OF DRY WINES IN HOT COUNTRIES. 41 
 
 of the whole mass of fermenting grapes. This difference of 10 degrees 
 simply represents the amount of heat which it is necessary to remove 
 during one cooling, and is useful in indicating the amount and the 
 temperature of the water needed. While the cooling is going on, fer- 
 mentation and the production of heat continue, so that though the must 
 passing through the cooler may be reduced 10 degrees or more, the 
 whole mass in the vat will be reduced very much less or even not at all. 
 The good effect consists, in the latter case, not in cooling the fermenting 
 mass, but in preventing its temperature from rising any higher. 
 
 A description of the common Algerian practice in cooling will make 
 this clearer. As a rule, the fermenting-vats are made of such a size 
 that two of them will contain exactly the amount of grapes gathered 
 in one day. One is filled in the morning and another in the afternoon. 
 When the temperature of the first vat reaches 35° C. the faucet at the 
 bottom is attached to a pump and the hot must passed slowly through 
 the cooler and back into the vat again. The must as it leaves the 
 cooler may have a temperature of 25° C. to 30° C, but it is fermenting 
 and producing heat meanwhile as are the other contents of the vat, so 
 that there may be very little if any apparent reduction of temperature 
 in the vat. The sugar, however, is disappearing, until a time comes 
 when, though the temperature of the vat may still be nearly 35° C, 
 there is not enough sugar left in the must to heat it above that point. 
 In fact, the usual plan in Algeria is to start pumping through the 
 cooler as soon as the must reaches 35° C, and to continue this pump- 
 ing until the fermentation is practically finished, that is, until only 2% 
 to 3% of sugar is left. If the temperature is then, say, 34° C. and has 
 never exceeded 35° C, there is no danger of the vat "sticking." This 
 pumping through the cooler occupies eight or twelve hours for each vat, 
 and is kept up night and day. This explains the arrangement of hav- 
 ing two vats filled per day. One is cooled at night and the other during 
 the day. Every vat is cooled, and cooled but once. When the weather 
 is warm and the grapes very sweet, the wine is kept going through the 
 cooler for a longer time. On the other hand, cool weather and grapes 
 of low sugar-content necessitate less time. The size of the vats, the 
 size of the cooler, and the amount of water should be so calculated that 
 twelve hours' pumping in the hottest weather with the sweetest grapes 
 expected will remove the necessary amount of heat from half the grapes 
 crushed in one day. In hot weather, when the grapes are warm when 
 crushed, it will be necessary to cool twice; but the total time of both 
 coolings should never exceed the twelve hours, or an extra machine 
 should be kept in reserve for exceptionally hot weather. 
 
 In order to show what a cooler of this type may be expected to do 
 under California conditions, the following figures have been calculated 
 on the basis of actual experiments made.* The estimate has been 
 
 * " Revue de Viticulture," vol. 7, p. 365. 
 
42 UNIVERSITY OF CALIFORNIA— EXPERIMENT STATION. 
 
 made for a cellar receiving a maximum of 100 tons a day in hot 
 weather.* In cool weather more could be handled: 
 
 Cooling by Miintz and Rousseau 1 s Machine. 
 (Average case.) 
 
 Grapes containing 22% of sugar, capable of developing 51.7° F. 
 
 Temperature of grapes at crushing 70.0 
 
 Total degrees of temperature '. 121.7 
 
 Maximum temperature desired 90.0 
 
 Number of degrees necessary to be removed 31.7 
 
 Less 6.7° F. from radiation 25.0 
 
 Temperature of water 65.0 
 
 (If the must is cooled to 77^° F. as soon as it reaches 90° F. it would require 
 two coolings to remove the necessary 25 degrees.) 
 
 Wine to cool in 20 hours 24,000 gallons 
 
 Water required 48,000 gallons 
 
 Machines needed, 1. (Capacity of M. & R. machine, 2,400 gallons per hour.) 
 
 If the grapes contained 24% of sugar and their temperature at crush- 
 ing was 80° F. and that of the water available 70° F., which is an extreme 
 case, two machines would be necessary and twice the amount of water. 
 The cost of the water is merely nominal if the cellar is near an irri- 
 gating ditch. Recent investigations of pumping plants in practical use 
 in irrigation show that on the average 300,000 gallons can be raised 10 
 feet for about $l.f 
 
 For a cellar of the size supposed, viz: one crushing about 100 tons 
 of grapes per day, two coolers would be necessary, of the capacity of 
 Miintz and Rousseau's largest size and an available supply of about 
 100,000 gallons of water per day, the temperature of which should never 
 exceed 70° F. This would make it possible to prevent the wine ever 
 surpassing 90° F., even in the hottest weather, and under average con- 
 ditions not more than half the water and only one machine would be 
 used. 
 
 Most of the large cellars of California are situated where they can 
 obtain an abundant supply of water by pumping. This is especially 
 true in the hotter regions, where irrigation is practiced. In this we have 
 a great advantage over Algeria, where water is very frequently scarce. 
 The various ingenious devices invented in Algeria for cooling the water 
 before using would be of little use here, because it would hardly ever be 
 necessary to use the same water twice, and cool water can be obtained 
 in nearly all cases. Regular observations made by the Irrigation 
 Department of the University of California show that the temperature 
 of the main irrigating canals in the San Joaquin Valley during the 
 wine-making season varies between 60° and 70° F., which is quite cool 
 enough for the purpose. 
 
 * Newer forms of this type of cooler are even more efficient. See " Progres Agricole 
 et Viticole," vol. 30, p. 19. 
 
 t S. Fortier: Circular No. 50, Office of Experiment Stations, Washington, D. C.,p. 10. 
 
MANUFACTURE OF DRY WINES IN HOT COUNTRIES. 
 
 43 
 
 Another type of cooler commonly used consists of a long copper or 
 galvanized iron pipe laid in a long trough. The wine is pumped through 
 the pipe and the water flows in the trough in the opposite direction. 
 The device is simple, easily constructed at the cellar, and is not costly. 
 Its main defect is that it does not thoroughly utilize the cooling capacity 
 of the water, and much more water is necessary. Where large quanti- 
 ties of cool water are available, as near a main irrigating canal, it 
 should be very useful. A good example of this type of cooler is in 
 
 Horizontal section. 
 
 
 
 
 
 
 
 
 
 
 
 
 w 
 
 
 
 w 
 
 <*> 
 
 w 
 
 
 
 w 
 
 W 
 
 (?) 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 Fig. 4. 
 
 Vertical section. 
 Plan and section of a wine cooler at Le Grand Craboules, Narbonne. 
 
 operation at the cellar of M. Gaston Gautier near Narbonne. At this 
 cellar is made about 500,000 gallons of wine yearly. The trough is 
 made of six walls of concrete about 2 feet high and 4 inches thick, so 
 arranged that the water flows from one end to the other in a zigzag 
 course. The galvanized iron* pipe through which the wine runs is laid 
 near the bottom of this trough. The machine is said to run all the 
 
 *The pipe should be tinned, not "galvanized," as in the latter case the zinc covering 
 will be quickly corroded by the acids of the wine, and zinc will contaminate the wine. 
 
44 UNIVERSITY OF CALIFORNIA— EXPERIMENT STATION. 
 
 season without cleaning, and remain effective to the end. At the 
 end of the season the wine pipe is taken apart at the joints and cleaned. 
 Such a cooler as this could be very easily constructed on the bank of 
 an irrigating canal, or the piping might even be placed directly in the 
 canal. 
 
 Ice.— The cooling power of ice might be used very effectively to pre- 
 vent hot fermentations, if it could be obtained cheaply enough. For 
 white wine, it is easily applied by placing the ice in a tinned copper 
 tub floating on top of the must. The hottest must rises to the top and 
 is cooled by contact with the tub and falls to the bottom. This creates 
 a circulation of the liquid, which maintains a uniform temperature in 
 all parts of the vat. For fermenting masses of crushed grapes this 
 method is not applicable. In this case the ice could be used to cool 
 the water used with an ordinary refrigerator. Five pounds of ice will 
 reduce 100 gallons of must about one degree Fahrenheit. To reduce 
 the must 20 degrees Fahrenheit, as in the case instanced on page 40, it 
 would require over one pound of ice for every gallon of must. This may 
 be taken as about the average cooling necessary, so that for every ton of 
 grapes, when used for white wine, 200 pounds of ice would be needed, 
 and about 300 pounds for the same amount of grapes when used for 
 red wine. If used in connection with a water refrigerator, simply to 
 increase the coolness of the water where only warm water was available, 
 would require under ordinary conditions about the same amount. 
 
 The cost of cooling for ice alone would amount to about $1.50 per ton 
 of grapes, reckoning ice at \ cent per pound, which is about 1 cent a 
 gallon for the wine made. This is much more than the whole cost of 
 cooling, including labor, where it is possible to get cool water. 
 
 The method, which has been tested in California, of placing the ice 
 directly in the vat with the idea of cooling and reducing the sugar at the 
 same time, is quite inadmissible. The amount of ice necessary would 
 introduce far too much water into the must. 
 
 CHEMICAL COOLING DEVICES. 
 
 The rise of temperature in a vat of fermenting grapes is due to the 
 fact, already noted, that more heat is produced in a given time by fer- 
 mentation than is lost by radiation and conduction in the same time. 
 The heat produced is limited by the amount of fermentable sugar 
 present; the heat lost, by the time of fermentation. If the fermentation 
 is rapid the excess of heat produced, over that lost in a given time, will 
 be great, and the rise of temperature correspondingly great. If on the 
 contrary the fermentation is slow, the excess will be less and the rise of 
 temperature less. If the fermentation is slow enough, the heat lost may 
 equal the heat gained and no rise of temperature at all take place. 
 
MANUFACTURE OF DRY WINES IN HOT COUNTRIES. 45 
 
 Anything, therefore, which retards fermentation will lower the maxi- 
 mum temperature to which the grapes will rise. Various substances 
 may be added to the must which have this effect of retarding the course 
 of fermentation. The only one which has come into practical use is 
 sulfur ous acid in some form. There are two sources of this acid 
 which are at present extensively used in wine-making. When sulfur is 
 burned it produces sulfurous acid gas. One pound of sulfur on burn- 
 ing yields two pounds of sulfurous acid. The other source is a salt 
 of sulfurous acid, potassium meta-bisulfite, often sold commercially under 
 the incorrect name of potassium sulfite. When this salt is placed in 
 must or wine it is broken up by the acids in the wine, and yields sul- 
 furous acid equal to 57% of its weight. The cost of the sulfite is about 
 23 cents per pound in France, and that of sulfur less than 2 cents. As 
 the former yields only one fourth as much sulfurous acid as the latter, 
 the cost of material is about fifty times as great. The difference in cost 
 of material is in many cases, however, counterbalanced by the greater 
 ease with which the sulfite can be used. 
 
 Sulfur. — The fumes of burning sulfur have long been used in the man- 
 ufacture of white wine in all wine-making countries. The finest white 
 wines of the Rhine and Gironde are sulfured in this way very heavily. 
 Some of the finest of the former contain as much as .20 per mil. to .26 per 
 mil. of sulfurous acid. Sauternes and Graves of the Gironde contain sim- 
 ilar amounts. As this is many times as great as is needed for controlling 
 the temperature, and as practically all that is used disappears from the 
 wine during fermentation, the question of the legality or wholesomeness 
 of the practice does not come into consideration in the making of ordi- 
 nary wine. While the use of sulfurous acid has other advantages, 
 especially in the making of the wines mentioned, in ordinary cases one 
 of the chief benefits is the moderation of the rate of fermentation and 
 the consequent lower temperature. For this purpose it is used exten- 
 sively in southern France and to a less extent in Algeria. To give an 
 idea of the moderation of temperature realizable in the fermentation of 
 red wine, the following example may be given:* Two tests were made 
 with two closed vats of 3,750 gallons each. One vat of each pair was 
 sulfured and both filled at the same time with crushed Carignane grapes. 
 In Nos. 1 and 3, 2.2 pounds of sulfur was burned before filling. When 
 the temperature of these vats reached 86° F. the fumes from 1.1 pounds 
 of sulfur were pumped into the must. Twenty-four hours later this 
 treatment was repeated. Owing to the method of introducing the sul- 
 fur fumes there is no way of determining how much the must absorbed, 
 but probably not more than 10% or 20% of the amount produced. 
 
 * " Progres Agricole et Viticole," vol. 29, p. 536. 
 
46 
 
 UNIVERSITY OF CALIFORNIA— EXPERIMENT STATION. 
 
 Casks Nos. 2 and 4 were treated in every way the same as Nos. 1 and 3. 
 except that no sulfur was used. The following table shows the results: 
 
 Maximum 
 
 Tempera- Drawn off at 
 ture 
 
 Sugar 
 Remaining. 
 
 Alcohol in 
 
 Wine at 
 2 Months. 
 
 Vat No. 1, sulfured . 
 Vat No. 2, no sulfur 
 Vat No. 3, sulfured . 
 Vat No. 4, no sulfur 
 
 93 c 
 102 
 
 95 
 104 
 
 8 days 
 
 9 days 
 9 days 
 
 10 days 
 
 
 2 
 
 2.5 
 
 13.5 
 13.0 
 13.9 
 13.3 
 
 In spite of the retarding effect of the sulfurous acid the fermentation 
 in the sulfured vats finished first. Though the fermentation in the 
 unsulfured vats was most rapid at first, the great heat developed 
 stopped the action of the yeast before all the sugar had disappeared, so 
 that the last 2% of sugar required several weeks to ferment out. 
 
 The alcohol in the sulfured wines was about a half per cent higher 
 than in the others, a difference due in great part probably to loss from 
 evaporation while pumping-over the latter at a high temperature. 
 
 The amount of sulfurous acid needed to delay fermentation is indi- 
 cated by some tests made by Roos.* Must containing .05 per mil. of 
 sulfurous acid fermented three fourths as fast as without any, and must 
 containing .1 per mil. fermented less than one half as fast. These fig- 
 ures can be used only as indications of where to commence trials in 
 practice, for the amount necessary will depend on a variety of condi- 
 tions which differ for every cellar, viz, composition of must, tempera- 
 ture of grapes and cellar, amount of aeration, kind and quantity of 
 yeast present, and size of fermenting-vats. The amount necessary 
 depends especially on the amount and kind of yeast present. If the 
 sulfurous acid is added before fermentation starts, a small amount 
 delays fermentation considerably. In this connection Roos f gives the 
 following figures as a guide to the use of sulfurous acid in clearing 
 white must before fermentation : 
 
 To delay 10-12 hours _ - 030 gram per liter. 
 
 To delay 18-24 hours 050 gram per liter. 
 
 To delay 48-60 hours .075 gram per liter. 
 
 To delay 5-6 days - 100 gram per liter. 
 
 These results indicate that freshly expressed must, to which has been 
 added the amounts of sulfurous acid mentioned, will not show percepti- 
 ble fermentation until after the times mentioned. If these amounts of 
 the acid were added to must in full fermentation they would not stop 
 the action of the yeast, but would simply diminish its rate, as in the 
 experiments mentioned on page 45. Therefore, the larger the amount 
 of yeast present the more sulfurous acid is needed to delay or check fer- 
 
 *"Progres Agricole et Viticole," vol. 29, p. 225. 
 t Roos: " Industrie Vinicole Meridionale," p. 234. 
 
MANUFACTURE OF DRY WINES IN HOT COUNTRIES. 47 
 
 mentation. The kind of yeast also influences the result. Some yeasts 
 are much more sensitive to the action of the acid than others. Part of 
 the good effect of a preliminary sulfuring of the must is that the true 
 wine-yeast is more resistant to sulfurous acid than most of the other 
 organisms present, and musts thus treated are therefore likely to 
 undergo a purer fermentation. Yeasts may even be selected with a 
 special resisting power, as in the process described on page 56. 
 
 The possibilities of cooling by the use of sulfurous acid are of course 
 limited by the amount of possible loss of heat by radiation. In warm 
 cellars, or in very hot weather, the temperature will run up too high in 
 spite of sulfuring. The same is true of fermentations in large vats. The 
 method is, therefore, of limited use, and while very effective in small 
 cellars and cool climates is usually insufficient under other conditions. 
 
 In the south of France the white musts are always treated with the 
 fumes of burning sulfur. The old method was to burn a certain quan- 
 tity of sulfur in each cask before introducing the must. Now the 
 must is usually passed through a "sulfurizer" and then pumped into 
 the casks. In both methods there is great uncertainty as to how much 
 sulfur fumes are absorbed. In the first method only a portion of the 
 fumes are taken up by the must, the remainder being expelled with the 
 air as it is forced out of the cask by the must. The difficulty is not so 
 great, however, in practice as it seems a priori. 
 
 If a small quantity of sulfur is burned, nearly all the fumes are 
 absorbed, while if a large quantity is burned, the greater part escapes. 
 Practical tests, under ordinary cellar conditions, show that if all the 
 sulfur possible is burned in a small cask, the must when introduced in 
 the ordinary way through a hose will absorb about .1 per mil. of sulfur- 
 ous acid. If only one seventh of this possible amount is used the must 
 will absorb .05 per mil., or half as much. That is, if we burn 2.7 ounces 
 of sulfur in a 100-gallon cask it will have only twice the effect of burning 
 .4 ounce. The amount necessary for defecating the must or for moder- 
 ating the heat of fermentation lies between these two extremes of .1 per 
 mil. and .05 per mil., so that when the fermentations take place in small 
 casks the rough guess of the cellarman as to the quantity of sulfur 
 to burn is usually near enough for practical purposes. With large 
 casks this is not always true, as the sulfur fumes are absorbed more 
 completely. The absorption, however, is not complete enough, even in 
 this case, to make the amount of sulfur burned a sufficient measure 
 of the amount of sulfurous acid introduced into the must. 
 
 Many ingenious devices exist for causing the must to absorb all the 
 sulfur fumes produced and so to make it possible to introduce an 
 exact amount. These devices are of two types: In one, the must passes 
 through an apparatus placed in the bunghole of the cask, so constructed 
 that all the fumes coming out of the cask pass through the incoming 
 
48 
 
 UNIVERSITY OF CALIFORNIA — EXPERIMENT STATION. 
 
 must and are therefore absorbed. In the other, the cask is filled first 
 and the sulfur fumes are then forced into the cask by means of a pump. 
 Most of the devices of the first type are cumbersome, troublesome to put 
 in place, and are little used. One of the simplest is the Brise-jet of 
 
 Fig. 5. Brise-jet. 
 R, hose for entrance of wine; T, cover of manhole to which is attached by cords a 
 small piece of wood, P, on which the entering wine strikes and is broken up into 
 a spray. 
 
 Roos, shown in Figs. 5 and 6. By means of this simple device the incom- 
 ing stream of must is thoroughly broken up into a spray, and tests 
 show that only from 1% to 5% of the sulfur fumes escape. This is quite 
 close enough for practice. It can not, of course, be used except where 
 
 Fig. 6. Illustrates method of causing absorption of sulfur fumes by means of Brise-jet. 
 
 F, cask containing wine or must to be sulfured ; A, suction hose of pump, P ; R, delivery 
 
 hose conducting wine into cask, F, in which sulfur has been burned; J, Brise-jet. 
 
 there is a manhole on the top of the cask. For casks with only a bung- 
 hole on top a long tube pierced with small holes may be adapted to the 
 end of the hose, but the absorption is then not quite so complete. 
 
 The second type of sulfurizer is exemplified by Fig. 7. The correct 
 amount of sulfur is weighed and placed in an iron pan beneath a cask 
 from which one head has been removed. The suction hose of a pump 
 
MANUFACTURE OF DRY WINES IN HOT COUNTRIES. 
 
 49 
 
 is then attached to the bunghole of the inverted cask, and as the fumes 
 are given off they are driven by the pump into the must, preferably 
 through a hose inserted through the upper bunghole. This method is 
 very effective for introducing large quantities of sulfurous acid, but is 
 little used. The hot sulfur fumes are apt to injure the hose and pump 
 and the method is troublesome to use in large cellars. 
 
 The sulfurizers used in most of the cellars which make large quanti- 
 ties of white wine are similar in principle to the one shown in Fig. 8. 
 An examination of the figure (8) will make clear the principle of the 
 machine. The must enters by the hose shown at the upper right-hand 
 corner of the figure, flows from shelf to shelf through the sulfuring cham- 
 
 Fig. 7. Method of sulfuring must with a pump. 
 M, small cask with one head removed, serving as a chamber in which to burn the 
 sulfur; /, /, openings for entrance of air; a, r, hose through which the sulfur 
 fumes are forced into the cask of wine by means of the pump, P. 
 
 ber into a reservoir below. The sulfur fumes generated in the stove 
 slfown at the lower right-hand corner of the figure enter the sulfuring 
 chamber near the bottom and take a zigzag course to the top where the 
 current of air which carries them escapes through a narrow chimney. 
 This arrangement insures a thorough contact between the must and 
 the sulfur fumes. 
 
 The sulfurous acid is so completely absorbed in this machine that there 
 is no odor of burning sulfur at the opening O where the air escapes. 
 The quantity of acid absorbed by the must depends on the amount of 
 sulfur burned and the rate at which the must passes through the appa- 
 ratus. It is possible thus to approximate a certain dose in sulfuring 
 
50 
 
 UNIVERSITY OF CALIFORNIA — EXPERIMENT STATION. 
 
 the must, but hardly more closely than by the old method of burning 
 the sulfur in the casks. The chief merits of the machine are saving of 
 labor and of the inconvenience and difficulty of burning sulfur in 
 the casks, especially when they are large. At the cellar of Villeroy, 
 near Cette, where 1,000,000 gallons of white wine are made annually, 
 all the must is sulfured by two machines constructed on this principle. 
 Any of these methods can be effectively used in the manufacture of 
 white wine where the dosing of the sulfurous acid has not to be done 
 
 Fig. 
 
 Paul sulfurizer. 
 
 with a great deal of exactness. For red wine they are very imperfect, 
 both because of the greater difficulty of introducing the fumes into the 
 crushed grapes, and of the greater need for precision in the doses. 
 
 Sulfites. — Sulfurous acid has a strong bleaching action on many sub- 
 stances, and if used in red wine tends to decolorize it. This decoloriz- 
 ing may be very considerable if large quantities are used, as is shown 
 
MANUFACTURE OP DRY WINES IN HOT COUNTRIES. 51 
 
 by a test made by A. Bouffard.* Various amounts of the acid were 
 added to a wine, and the loss noticed as follows : 
 
 Sulfurous Acid per mil. Loss of Color. Loss at One Month. 
 
 •025 7% _. 3% 
 
 .050 .._. 12% 6% 
 
 .075 — - 25% 20% 
 
 .100 35% 30% 
 
 The second column shows the amount of color lost immediately after 
 sulfuring when compared with the unsulfured wine. A month later the 
 difference was much less, especially for the small doses. The loss 
 is in any case, however, much less than appears at first. The color is 
 not all destroyed and reappears to a great extent as the sulfurous acid 
 disappears from the wine either by escaping into the air during racking 
 or by becoming oxidized to sulfuric acid, or by forming various chemical 
 combinations with substances in the wine. Moreover, the color which 
 is left is more brilliant and more stable than that in an unsulfured wine. 
 As there certainly is some loss, however, especially with large doses, it is 
 necessary to use no more than is absolutely necessary to control the 
 temperature. For this reason potassium meta-bisulfite is nearly always 
 used in preference to burning sulfur when treating grapes and must for 
 red wine. 
 
 The bisulfite is very easily soluble, and may be dissolved in a little water 
 which is added to the grapes gradually as they are crushed, care being- 
 taken to distribute it well in all parts of the vat. To give a dose of .05 
 per mil. of sulfurous acid it would be necessary to add one-fifth of a 
 pound of sulfite to every ton of grapes. This would cost about 6 or 7 
 cents. The sulfur necessary for the same dose would cost but a small 
 fraction of a cent, but would be more troublesome and therefore costly 
 to use, besides being less reliable. 
 
 POSTPONEMENT OF FERMENTATION UNTIL WINTER. 
 
 One of the great advantages that the vineyards of the high Little Atlas 
 mountains and the elevated plateaus of Algeria have is that the weather 
 is cool during the fermenting season. This is due partly to the eleva- 
 tion and partly to the late ripening of the grapes. If it were possible 
 in the warmer parts to prevent fermentation of the grapes until cool 
 weather, it would be comparatively easy to prevent hot fermentations. 
 This can, in fact, be done by treating the crushed grapes with a sufficient 
 quantity of sulfite. The amount necessary depends on the condition 
 and composition of the grapes, the temperature of the cellar, and the 
 amount of yeast present. Clean, acid grapes can be crushed and kept 
 in a cool cellar for months by adding .5 mil. of sulfurous acid or two 
 pounds of sulfite to every ton. Grapes with little acid or which have 
 commenced to ferment, or which are kept in a warm place, would 
 
 *Bouffard, A.: " La Casse des Vins," p. 24. Montpellier, 1902. 
 
52 UNIVERSITY OF CALIFORNIA— EXPERIMENT STATION. 
 
 require more. The smaller amount, however, is sufficient to injure the 
 color of red grapes considerably. While the method might be used 
 for white grapes or must, it is not practicable for red grapes with the 
 present arrangement of cellars, as it would necessitate a large increase 
 of vats or other cooperage. 
 
 FERMENTATION IN A COOL LOCALITY. 
 
 Large quantities of grapes, crushed grapes and must, are transported 
 from the south of Europe to the north for wine-making purposes. This 
 is not done, however, primarily for transferring them to a climate more 
 favorable to fermentation. Grapes are sent from Italy and France into 
 Germany for the purpose of supplementing the watery, acid, and badly 
 ripened grapes of the latter country, and as part of the raw material of 
 the innumerable vintages fabricated at Hamburg and elsewhere. Some 
 of these grapes are transported in baskets, barrels, or vats as they are 
 gathered, but the greater part are crushed before sending. When the 
 distance is short no precautions are taken to prevent fermentation, but 
 where the distance is over two or three days the crushed grapes and 
 must are usually preserved with sulfurous acid. The amount used is 
 about .4 per mil., or about 1-J pounds of sulfite to the ton. This is suffi- 
 cient to paralyze all the yeast present and to prevent any danger of 
 fermentation on the journey. Fresh must from sound grapes treated 
 with this amount will usually keep for several months. 
 
 There is no doubt that if the grapes of the San Joaquin Valley 
 could be transported to the Bay Region cheaply enough, there would be 
 little more difficulty in fermenting them than the grapes of the coast 
 valleys. This is proved by the wines made at the California Experiment 
 Station cellar from grapes shipped from Tulare. It is simply a question 
 of cost and shipping facilities. The extra freight charges would be con- 
 siderable, as the weight of the grapes is about two-thirds greater than 
 that of the wine they make. There would, besides, be the cost of boxes 
 or other receptacles. In parts of Italy and Algeria crushed grapes are 
 transported in specially constructed iron tanks on railway trucks. Sul- 
 fites could be used only for white wines, on account of the large amount 
 necessary. In any case there would have to be sufficient guaranty 
 that the grapes would not be more than two days from the time 
 they were put on the truck to the time they were placed in the ferment- 
 ing-vats. 
 
 In order to economize in freight charges many attempts were for- 
 merly made to concentrate the grapes or must before shipping. No 
 advance seems to have been made, however, over the methods of Springh- 
 miihl, which were thoroughly tested in California, and those of Favara 
 in Sicily. The method is fairly successful for the making of sweet 
 wines, but these can be made as well or better in hot countries. For 
 
MANUFACTURE OF DRY WINES IN HOT COUNTRIES. 53 
 
 dry wines the concentrated grapes and must have failed, being little, if 
 at all, better than dried grapes for this purpose. 
 
 CONTROL OF THE FERMENTATIVE AGENTS. 
 
 The various cooling devices just discussed act, in so far as they 
 prevent imperfect or deleterious fermentations, by controlling the fer- 
 mentative agents. That is, they keep the fermenting mass at a tempera- 
 ture favorable to the true wine-yeast whose action we want to assist, 
 and less favorable to the bacteria and other injurious organisms whose 
 action we want to hinder. Cooling, however, only hinders the growth 
 of the latter, but in no case completely prevents it. Under favorable con- 
 ditions this action is so slight as to be practically inappreciable; under 
 less favorable conditions the freshness and bouquet of the wine may be 
 impaired, or in extreme cases the wine spoiled. These are, however, 
 only differences in degree. If we could find some means of absolutely 
 excluding all organisms from the must except the true wine-yeast, we 
 should get none of the defects due to injurious secondary fermentations 
 under any conditions. 
 
 Pure Yeasts. — With this object in view various methods have been 
 devised for sterilizing the grapes and must; that is, of freeing them from 
 all micro-organisms of any kind, and subsequently fermenting them by 
 adding a pure yeast. A pure yeast is a liquid containing no micro- 
 organisms but yeast cells and only one kind of yeast cell. For about 
 twenty years, extensive laboratory and practical tests have been made 
 with these methods, but there is still wide divergence of opinion as to 
 their merits. There is perfect unanimity of opinion as to the value of 
 eliminating unfavorable organisms, but on the value of the use of pure 
 yeast there is much difference of opinion. On one side it is claimed 
 that the character of Chateau Iquem or of Clos Vougeot may be given 
 to the wine from any grape, or even from apples, wherever grown, by 
 the use of a pure yeast selected from the vineyards which produce these 
 famous wines. Factories are in existence which are ready to supply 
 yeasts from any one of the hundreds or thousands of famous wines of 
 the world, with the implied assurance that they will enable any wine- 
 maker to produce these famous wines anywhere. Much of this is no 
 doubt due to the exaggeration inseparable from advertising. The claims 
 of certain laboratory investigators of pure yeasts, however, fall little 
 short of those of the vendors of pure yeast for wine-making, and are 
 undoubtedly in many cases excessive and misleading. At all events 
 they are not substantiated by results in practice, or by the work of 
 other investigators. On the other hand, it is an equally great mistake 
 to suppose that the purity or selection of the yeast has no effect on the 
 wine. The comparative purity of the yeast is the object of a great part 
 5— bul. 167 
 
54 UNIVERSITY OF CALIFORNIA— EXPERIMENT STATION. 
 
 of the care taken wherever good wines are made, and there is no doubt 
 about the great differences which exist in different yeasts and in their 
 effects on the wine. 
 
 It is just here that there is danger in the use of absolutely pure 
 yeasts prepared by modern methods. While it may not be possible 
 to make the difference between a " Rommanee Conti" and a " Chateau 
 Lafitte" wine by a proper selection of yeasts, there can be no doubt 
 whatever that it is possible to make the difference between a good 
 wine and a bad wine from the same material according as we use 
 an appropriate yeast or an inappropriate one. We can not make good 
 wine from any grapes by the use of pure beer-yeast, bread-yeast, or any 
 of the hundreds of yeasts which we can find almost anywhere. More- 
 over, it is quite possible to select from grapes pure yeasts which have 
 very different effects on the wine in fermentation. Some pure wine- 
 yeasts will not give good results at high temperatures, others at low; 
 some will not cause the fermentation of more than 18% of sugar, others 
 can ferment 26% and so on. If, therefore, we use pure yeasts we must 
 use selected pure yeasts; yeast selected and tested for the particular 
 purpose in hand. 
 
 Most of the pure yeasts distributed in Germany and France have 
 been properly selected, and in spite of the exaggerated claims of 
 the makers, usually give good results when properly used. It would, 
 however, be quite possible to completely spoil wine by the use of a 
 pure yeast not properly selected for the particular must in which 
 it is placed. This is no doubt the reason why pure yeasts obtained 
 from the regions where they are to be used have nearly always given 
 better results than yeast imported from other regions. It is far more 
 likely that a pure yeast separated from fermenting Fresno grapes will 
 prove resistant to high temperatures and capable of fermenting very 
 sweet must, than one separated from grapes grown on the Rhine. The 
 yeasts which exist in any region have undoubtedly been subjected for 
 ages to a process of natural selection which has fitted them for the con- 
 ditions of that region. Rhine yeast will, therefore, not help us to make 
 Rhine wine in Napa County, unless we can get grapes whose composi- 
 tion approaches those of the Rhine, and can imitate the temperature 
 and other conditions usual in the Rheingau.* 
 
 To obtain the best results from the use of selected yeasts in promoting 
 a thorough fermentation or improving the wine in any other way, a 
 more or less complete sterilization of the grapes or must is necessary. 
 Very numerous trials have been made, with this object in view, during 
 the last twenty years. While the question of the degree of improve- 
 ment to be attained by the use of selected yeast is not yet settled, the 
 
 *See, for a good practical example of this:— Report of Viticultural Work, College of 
 Agriculture, Berkeley, 1887-93, pp. 400-402. 
 
MANUFACTURE OF DRY WINES IN HOT COUNTRIES. 55 
 
 attempts at sterilization have brought to light some unforeseen but very 
 important facts regarding the effect of the methods used in the process 
 of wine-making. 
 
 Attempts have been made to free must from fermentative organisms 
 in various ways ; but only two, so far, have given good results or been 
 adopted in practice. These are sterilization by heat and sterilization 
 with sulfurous acid. 
 
 Twenty years ago Louis Marx and others attempted to sterilize musts 
 by heat for the purpose of fermenting them with pure yeast. The 
 results, while promising, were not completely successful, on account of 
 the cooked and "rancio" taste of the wines made. These tastes were 
 due to the imperfect appliances with which the experiments were made. 
 Later, Rosenstiehl, starting from the known facts, that the cooked or 
 raisin taste was due to heating the must too high and the consequent 
 caramelization of a portion of the sugar, and the " rancio" taste due to 
 the exposure of the hot must to the oxygen of the air, invented and 
 patented a process of sterilizing the must at a low temperature and out 
 of contact with the air. The first defect was remedied by heating the 
 must three times to a comparatively low temperature, allowing an 
 interval to elapse between successive heatings. This had the effect of 
 killing all germs in the must as effectively as a single heating to a 
 higher temperature. The second defect was avoided by keeping the 
 must in an atmosphere of carbonic acid gas during the heating. 
 
 Rosenstiehl's method, while effective, was slow, and required compli- 
 cated and expensive machinery. Later it was shown, principally by 
 the researches of Kayser and Barba at Nimes, that the object which 
 Marx and Rosenstiehl had in view, the absolute sterilization of the 
 must, is not necessary in ordinary wine-making; and further, that the 
 absolute exclusion of the air during heating, which Rosenstiehl 
 attempted, is also unnecessary. All that is necessary in the first respect 
 is that the must shall be "pasteurized"; that is, heated to such an 
 extent that all active germs are killed. If a few germs in the latent 
 or spore condition are left, they are absolutely innocuous, as they can 
 not develop in time to do any harm. Before they have multiplied 
 sufficiently, the wine is made and safe from their attacks. It is pos- 
 sible, therefore, to eliminate the injurious germs sufficiently by one 
 heating to a temperature too low to caramelize any sugar. 
 
 With regard to the "rancio," it was found that must or grapes could 
 be heated as high as necessary without acquiring this taste, if the 
 exposure to the air was not excessive or continued for too long. It has 
 lately been found possible, by the addition of a little sulfite before 
 heating, to almost do away completely with any danger of oxidation, 
 even with considerable contact with the air, and at the same time to get 
 a more complete sterilization at a comparatively low temperature. 
 
56 UNIVERSITY OF CALIFORNIA— EXPERIMENT STATION. 
 
 Sulfiting. — A method which promises well for use in hot climates is 
 one devised by Martinand and Andrieu. It consists of adding a certain 
 amount of bisulfite of potash to the crushed grapes and the subsequent 
 addition of selected yeast. The addition of the sulfite is sometimes 
 spoken of as a "sterilization." It is doubtful if the amounts used are 
 sufficient to actually kill all germs in the must, but they are sufficient 
 to prevent them from developing for some time ; and in the meanwhile 
 the selected yeast has time to completely take possession and finish the 
 fermentation. 
 
 There are three ways of applying this method. The first is to add 
 sulfite to the fermenting grapes in two or three doses, and is practically 
 identical with the method already described (see page 46) for moderat- 
 ing the temperature by the same means. The other two methods differ 
 in that so much sulfite is used that ordinary yeast is paralyzed with the 
 other germs. For this reason it is necessary to have a special yeast 
 which is capable of acting in the presence of the amount of sulfurous 
 acid introduced into the wine. Such a special yeast is procured by 
 taking any good strong yeast and gradually accustoming it to grow in 
 the presence of large amounts of sulfurous acid. This is done in one of 
 two ways. The way recommended by Andrieu is to fill each of two 50- 
 gallon casks one-third full of must sterilized by heating. In the must 
 in one cask is dissolved .5 per mil. of potassium meta-bisulfite ; that is, 
 1 ounce to 15 gallons. The must in the other is started fermenting by 
 introducing a small flask full of pure yeast. As soon as the must in 
 the second cask is fermenting well, 5 gallons of the sulfited must from 
 the first cask is poured in. This will check fermentation temporarily, 
 but in a few hours the yeast becomes accustomed to the sulfurous acid 
 and fermentation commences again. As soon as fermentation is well 
 reestablished another 5 gallons is added ; and a few hours later the 
 remainder of the sulfited must. When the yeast is fermenting well after 
 the last addition of sulfite, it is ready to be used on a vat of grapes. 
 The grapes as they come from the crusher are sulfited with a dose of 
 potassium meta-bisulfite equal to that to which the yeast has become 
 accustomed, i. e., .25 per mil., or 2 pounds to 1,000 gallons or 4 tons. 
 This is sufficient to prevent all fermentation except that of the added 
 yeast. A pure fermentation is thus assured. 
 
 The other method is to train the yeast in the fermenting-vat itself. 
 This is done by adding a pure yeast to the grapes as they pass into the 
 vat, together with one-third of the amount of sulfite which is to be used, 
 /'. r>., two-thirds of a pound to the 1,000 gallons. This is enough to 
 retard but not to prevent fermentation. As soon as fermentation has well 
 started, another third of the sulfite is added, and then the remainder 
 when renewed fermentation shows that the effect of the second dose has 
 been overcome. 
 
MANUFACTURE OF DRY WINES IN HOT COUNTRIES. 57 
 
 All these methods have given excellent results in numerous cases, but 
 the second and third, and especially the second, are much more effective 
 than the first. 
 
 SUMMARY. 
 
 METHODS ADOPTED IN SOUTHERN FRANCE AND ALGERIA. 
 
 Modern wine-making in these regions has developed along different 
 lines, and each region has adopted a different method of overcoming the 
 difficulties connected with the making of dry wine in a hot climate. 
 
 In southern France these difficulties have been attacked principally 
 by means which aim at making the raw material more amenable to the 
 conditions and methods of manufacture which exist there. The suc- 
 cessful production of dry wines, there, depends in a large measure on: 
 (1) the planting of the Aramon, a vine which produces grapes of high 
 acidity and low sugar; and (2) on the gathering of all varieties before 
 they are perfectly ripe. While the trouble of incomplete fermentations 
 are thus, to a great extent, avoided and a sound wine generally made, 
 the result is not altogether satisfactory. During the epoch immediately 
 following the destruction of most of the vineyards by phylloxera (1890- 
 1899), the abundant crops of thin, watery wine were very profitable. 
 Now, when the supply has caught up to or passed the demand, the 
 price obtained for the wine is often below the cost of production. A 
 very large proportion of the Aramon wines can not be marketed without 
 blending with heavier wines, and in years when the crop is large the 
 price falls very low. In 1904 large cellars sold their crops at less than 
 6 cents per gallon, and the average price was probably not much over that 
 figure. The wine has to be blended with Algerian or Spanish wines, 
 and the wine-merchant can afford to give but little more for it than for 
 piquettes and sugar wines. 
 
 In Algeria the Southern French method could not be applied. 
 There, even the Aramon often attains too much sugar to ferment out 
 completely without aid, and the grapes ripen so rapidly in the hot 
 autumn that it is impossible to gather them all before they are quite 
 ripe. Moreover, in the hot weather which is often experienced during 
 the wine-making season in Algeria, grapes, even with low sugar-con- 
 tent and high acidity, may fail to complete their fermentation. Even 
 if the Southern French method were possible, it would be impracticable 
 in Algeria, where it would always be unprofitable to produce light 
 blending wines in competition with the Midi. The demand for Alge- 
 rian wines is based on their capability of correcting the defects o (he 
 Midi wines, and, to retain their market, they must be alcoholic and rich 
 in tannin, color, and extract. Some means, therefore, had to be found 
 which would enable the wine-makers to ferment Alicante Bous 'net, 
 Carignane, and similar grapes with 22% to 26% of sugar. The only 
 
58 UNIVERSITY OF CALIFORNIA— EXPERIMENT STATION. 
 
 method which has come into general use is that of keeping down the tem- 
 perature with cooling machines. This, as already noted, has enabled 
 them to produce sound, alcoholic wines, but the moderation of the tem- 
 perature has entailed a loss in the valuable qualities of deep color and 
 high extract. In neither France nor Algeria, then, are the present 
 methods of manufacture completely satisfactory, and attempts at im- 
 provement are being made along all the lines discussed in this report. 
 On the whole, however, there is less loss from spoiled wine there than 
 with us, and a consideration of the methods of French and Algerian 
 wine-makers offers many suggestions of possible improvements in our 
 own methods. In no region, however, are the markets, raw materials, 
 and conditions of manufacture identical with ours, and we can not, 
 therefore, copy exactly any methods however successful elsewhere. 
 It is impossible, moreover, to point out any method or group of 
 methods that can be adopted here with absolute certainty of 
 success in all regions. It is possible, however, to point out certain 
 methods which, if adopted, will certainly result in great improvement 
 in many of our wines. The conditions of soil, climate and grape vari- 
 eties in Algeria resemble ours much more than do those of southern 
 France. The following short description of the most approved method 
 of vinification in Algeria should be of interest. It was kindly furnished 
 me by Dr. Roger Mares of Algiers, who is an expert authority on the 
 subject: 
 
 WINE-MAKING IN ALGERIA. 
 
 At the beginning of the vintage the juice of some well-washed grapes is placed in a 
 small, perfectly clean and sterilized cask, and the contents of a flask of pure selected 
 yeast added. The cask is placed in a clean room where there is no danger of infection 
 by bad germs from cellar, fermenting-room, or pomace heaps. The room is kept at a 
 favorable temperature (65° to 75° F.). 
 
 When the must is in violent fermentation it is added little by little to the vat as it is 
 being filled with crushed grapes. If the temperature of the grapes is between 77° and 
 86° F., fermentation commences immediately. 
 
 The fermenting grapes are stirred frequently, night and day, and the temperature 
 watched. The fermenting must is cooled as soon as it rises to 97° or 100° F. The tem- 
 perature should not be lowered below 86° F. 
 
 The wine should be perfectly dry in a few days. 
 
 Fermentation takes place in open vats not deeper than 5 feet 6 inches. It is best not 
 to have them exceed 11 feet in diameter, or the workmen find it difficult to stir them 
 from the sides. If made wider a plank is placed across the middle to support the work- 
 men while stirring. 
 
 The vats are made of masonry covered with cement, and cost about 2 cents per 
 gallon. 
 
 It is always best to have the fermenting-room about 100 feet from the storage cellar; 
 with this arrangement fermentation takes place better in the vats and the wine keeps 
 better in the cellar. The cellar should be placed on the windward side of the ferment- 
 ing-room. 
 
 Deep fermenting-vats are no longer built, and where they exist they are only partially 
 filled. 
 
 Pressing is usually done with screw presses, but occasionally continuous presses are 
 used, especially before fermentation when white wine is made. 
 
 Stemming is generally practiced, but if the grapes are clean and sound only a part of 
 I he Stems LB removed. 
 
MANUFACTURE OF DRY WINES IN HOT COUNTRIES. 
 
 59 
 
 The pressed pomace is used for the production of piquette by the sprinkling method. 
 The extraction of the wine from the pomace by the Roos method of displacement is 
 advisable, but has not yet come into practice. 
 
 Selected yeasts are used only for the first vats; for the following vats about fifty 
 gallons of fermenting must is taken from a previously filled vai and added gradually as 
 the crushed grapes come from the crusher. 
 
 This may be considered the most approved method of wine-making 
 at present in use in Algeria. It differs from the method in most general 
 
 V\( 
 
 Fig. 9. Algerian amphoras used for fermentation. 
 
 Cross-section of an improved arrangement of amphoras for fermentation and 
 
 storing. 
 
 use principally in the character of the fermenting-vats. The use of low, 
 open vats and a separate fermenting-room necessitates an outlay which 
 most Algerian wine-makers avoid by fermenting in the " amphoras" in 
 which the wine is stored. These amphoras are constructed of masonry, 
 concrete or brick, usually lined with glass. They resemble in shape 
 
60 UNIVERSITY OF CALIFORNIA— EXPERIMENT STATION. 
 
 huge bottles, and hold from 1,200 to 12,000 gallons each. The diminu- 
 tion in the amount of spoiled wine in Algeria is undoubtedly due in 
 some measure to the use of these amphoras, which it is possible to clean 
 and sterilize with the greatest ease. They have many advantages over 
 wooden casks or vats, especially for the handling of young wines. They 
 can be cleaned in a few minutes simply by washing with a hose, and 
 require no care when empty, as they do not shrink or become moldy, 
 like wooden cooperage. There is no evaporation of the wine when they 
 are filled, so that there is no loss of volume in keeping the wine, as with 
 oak and redwood casks. They utilize the space in a cellar better, as they 
 can be made of almost any shape and enable the wine-maker to store a 
 much larger volume of wine under a given roof. In Algeria they have 
 the further advantage of being considerably cheaper than oak casks. 
 Their only defect is that they prevent the aging of the wine. This is, 
 however, in Algeria an advantage, as the wine-buyers prefer a young, 
 well-defecated wine which they can transport to France and age in cool 
 cellars. The cost of these amphoras in Algeria ranges from 2 to 4 cents 
 per gallon, depending on their size, shape, kind and amount of glazing, 
 and the cost of transporting the material. 
 
 In comparing the relative cost of amphoras, oak casks, and upright 
 vats, account must be taken of the differences in space occupied. Wine 
 stored in round oak casks of 3,000 gallons capacity requires about 40 
 square feet of floor space for every 1,000 gallons. If stored in upright 
 vats holding 10,000 gallons, of the form of the redwood vats commonly 
 used in California, about 30 square feet is required per 1,000 gallons. 
 With amphoras of 10,000 gallons capacity, 1,000 gallons can be stored in 
 every 20 square feet. In other words, a cellar of one story with a floor 
 space of 100 by 100 feet will hold about 250,000 gallons of wine in 
 3,000-gallon oak casks, 350,000 gallons in 10,000-gallon redwood vats, 
 and 500,000 gallons in 10,000-gallon amphoras. 
 
 The cleanliness of the Algerian cellars visited was remarkable, 
 and in strong contrast to many of the large cellars of southern 
 France. The absence of woodwork and the liberal use of concrete make 
 the work of keeping the cellars clean comparatively easy, as do also the 
 simple and effective devices for handling grapes and pomace used by 
 most wine-makers. The ease with which bacterial infection passes 
 from cask to cask and from one vintage to another in hot climates has 
 taught the Algerian wine-maker the necessity of thorough and frequent 
 sterilization of everything with which the grapes or wine come in con- 
 tact. Concrete vats and amphoras, if suspected, are rapidly and easily 
 sterilized by swabbing with a 5/ Q solution of sulfuric acid, but usually 
 a simple washing with water is quite sufficient to keep them in good 
 condition. 
 
 For the sterilization of wooden casks and vats of all sizes small steam 
 
MANUFACTURE OF DRY WINES IN HOT COUNTRIES. 
 
 61 
 
 generators of a special form are much used both in France and Algeria, 
 and are very effective. They are portable and so constructed that they 
 produce dry steam superheated to over 500° F. under little or no pres- 
 sure. They are useful in large as well as in small cellars, even where a 
 
 Fig. 11. Medium-sized wine-cellar and fermenting-room. 
 
 
 
 
 
 
 
 p»f 
 
 
 1 
 
 
 1 
 
 
 , . ;, 'iV.' ■■■•'■* 
 
 
 
 ' i ■ f 
 
 
 
 
 ■v.' 
 
 , * ' \ 
 
 
 Sf t 
 
 
 
 
 1 
 
 
 
 
 ' ft 
 
 
 
 
 
 
 
 
 
 
 ^^H£ET'"/ 
 
 
 1 
 
 
 
 n 
 
 j 
 
 
 
 
 1 J^lm 
 
 
 
 
 
 
 Wk 
 
 
 
 
 1 I? 
 
 
 
 
 
 
 
 
 
 
 Bb M ~ 
 
 
 
 
 
 
 
 
 
 
 k| 
 
 
 ..* * 
 
 
 , 
 
 
 
 
 
 
 Fig. 12. Inside view of same cellar shown in Fig. 11. 
 
 steam boiler exists for other purposes. It is a great advantage to be 
 able to sterilize casks at any time, and one of these small cask steamers 
 can be heated up and used much more easily and rapidly than an ordi- 
 nary steam boiler. They also have the advantage that they can not 
 
62 
 
 UNIVERSITY OF CALIFORNIA— EXPERIMENT STATION. 
 
 explode, and the superheated dry steam they produce is much more 
 effective in penetrating and sterilizing power than the pressure steam 
 from an engine boiler. 
 
 Wherever separate fermenting-vats are used the tendency is to place 
 them in a building separate from the storage cellar. This building is 
 usually made very open, in fact is often simply a shed with open sides. 
 
 The figure on the cover of this bulletin shows the simple installation 
 of a wine-maker near Berrouaghia, which may be taken as typical of 
 small-scale wine-making in Algeria. It consists of an open shed cover- 
 ing three rectangular stone vats. The grapes are crushed into these 
 vats and, after fermentation, are stored in the same vats, which are 
 then covered with heads made air-tight with clay or plaster. The 
 
 Fig. 13. Open fermenting-room and shallow fermenting-vats of large cellar 
 
 in the Sahel. 
 
 arrangement seems very primitive, but for the purpose is both cheap 
 and effective. The small open vats are cooled off at night, so that only 
 when the sirocco blows is there much danger of a hot fermentation. 
 The wine is usually sold and shipped at the first racking, so that it is 
 not exposed to the hot weather of the summer following the vintage. 
 
 Figs. 11 and 12 show a good example of a medium-sized cellar where 
 from 10,000 to 20,000 gallons of wine are made. The sides of the cellar, 
 which is for both fermenting and storing, are very open. The fermenta- 
 tion takes place in open brick vats and the wine is stored in brick 
 amphoras. This cellar is in the Miliana region at a high elevation. The 
 vintage is late and the weather not usually very hot during wine-making. 
 The soil, the vineyards, and the wine in this district recall those of 
 
MANUFACTURE OF DRY WINES IN HOT COUNTRIES. 
 
 63 
 
 Howell Mountain and similar situations 
 in California. No cooling machines are 
 used in either of these cellars. 
 
 Fig. 13 shows a good example of a 
 fermenting-room of a large cellar in the 
 "Sahel," the low range of hills running 
 along the coast west of Algiers. Here 
 the grapes become very sweet, ripen 
 early, and the weather during the vint- 
 age is usually hot. The fermenting-vats 
 are shallow, raised about 5 feet from the 
 ground, and placed under an open shed. 
 They are made of armed cement and 
 have walls only about 4 or 5 inches 
 thick. The method of wine-making is 
 practically that advocated by Professor 
 Mares, described on page 58. Cooling 
 machines are used and every effort 
 made to keep the temperature of fer- 
 mentation low. As water is both scarce 
 and warm, two cooling towers have been 
 built to reduce the temperature of the water for the cooling machines. 
 Fig. 14 shows one of these towers with the large fan used to produce 
 the current of air necessary to cool the water. 
 
 Fig. 14. Cooling tower. Used in 
 connection with fermenting cellar 
 shown in Fig. 13. 
 
 CONCLUSIONS. 
 
 The main lesson of immediate practical importance to California 
 wine-makers to be learned from these observations and experiments is 
 the oft-repeated one of cool fermentation. It seems strange that in 
 Algeria, where cool water is far more scarce than in California, the 
 wine-makers should have been able to make the use of cooling machines 
 a practical success, while here little or no progress has been made in 
 that direction. The reason is to be found probably in a lack of a real 
 appreciation of the need and use of cool fermentation among the wine- 
 makers of the regions where dry wines are usually made, and of the 
 difficulty of applying known methods in the hotter regions, where the 
 cellars are nearly all of great size. 
 
 With regard to the first there is undoubtedly a very general lack of 
 realization of the benefits to be derived from fermenting wines at a low 
 temperature. A wine which attains a temperature of 95° to 100° F. 
 during fermentation will never have the freshness, bouquet and general 
 high quality of one which never exceeds 85° or 90° F. Even though 
 the former ferments out completely and remains a perfectly sound 
 
64 UNIVERSITY OF CALIFORNIA— EXPERIMENT STATION. 
 
 wine, its quality and especially its bouquet is injured, and the headiness 
 of many California wines, and of wines from other hot countries, is 
 undoubtedly due in great part to the high temperature of fermentation. 
 The greater intoxicating effect of a California wine with 13% of alcohol 
 over a Chateau Margaux with 11% can not be all ascribed to the slight 
 difference of alcoholic strength. The variability of even the best brands 
 of our California bottled wines is also in great part due to the lack of a 
 more perfect control of the fermenting temperature. The California 
 wines which a traveler finds in the Eastern States and in the hotels 
 and dining-cars of England and the Continent are undoubtedly much 
 superior to those he would have found there five or ten years ago, but 
 they are still often very disappointing to one who knows how good they 
 can be sometimes. The first step to be taken in establishing uniform 
 and reliable brands of fine California wines is for the wine-makers to 
 give their wines the uniform good quality which can only be obtained 
 by fermenting every vat at a uniform and low temperature. This will 
 render the work of the wine-blenders and handlers comparatively easy. 
 
 With regard to the production of common or bulk wines the problem 
 is somewhat different. Here the main object is to produce a sound 
 wine of good keeping qualities as cheaply as possible. The finer quali- 
 ties of bouquet, freshness, and lack of headiness are of less importance. 
 One of the essentials of cheapness is the production of heavy crops. Our 
 cheap wines must be made, then, from heavy-bearing varieties of vines 
 planted in rich soil. The vineyards of southern France, where common 
 wines are made, produce from 8 to 10 tons per acre, and even as much as 
 12 to 15 tons as the average for whole vineyards. The vineyards of the 
 Metidja Plain in Algeria produce as much. There are immense tracts 
 of land in the Sacramento and San Joaquin valleys which are capable 
 of producing equally large crops. The question is, can these crops be 
 turned into good, sound, dry, red wines. 
 
 Innumerable tests at the California Experiment Station cellar prove 
 that good, sound, dry wines can be made from grapes grown in rich, 
 irrigated and alkaline soil in Fresno and Tulare. The experiments 
 detailed on page 25 even show that wines of high quality can be made 
 from such grapes. There is nothing, therefore, in the nature of the 
 grapes themselves which will prevent the manufacture of good, dry 
 wines in the great central plain of California. It remains to be seen 
 whether a practicable method of wine-making can be devised which 
 will overcome the difficulties which have so far prevented the produc- 
 tion of such wines there. 
 
 The most promising direction in which to look for such a method is 
 at present in line with the experiments of Barba, and the Berkeley 
 Experiment Station. The method in short that offers an almost prac- 
 tical certainty of attaining our object is the following: — 
 
MANUFACTURE OP DRY WINES IN HOT COUNTRIES. 
 
 65 
 
 1. Heating the crushed grapes to a temperature and for a time suffi- 
 cient to extract the necessary color, tannin, and body. 
 
 2. Immediate separation of the must and cooling to 85° F. 
 
 3. Immediate fermentation of the must at a temperature not exceed- 
 ing 90° F. 
 
 This is not to be understood as a recommendation of this method for 
 immediate introduction into any cellar. The present status of the 
 method is this: 
 
 1. It has been shown, both in California and in France, that it is 
 possible, when working with small quantities, to attain the object in 
 view by this method. 
 
 2. The method has been used with success in France in the whole 
 output of a cellar manufacturing 75,000 gallons of wine in a season. 
 
 It remains now to be seen whether the method can be made practi- 
 cable for California conditions. A careful study of these conditions has 
 left little doubt in my mind that it can, and the failure of all other 
 methods that have been tested so far makes it very desirable that it 
 should be given a thorough trial. There are numerous details of the 
 method which have to be carefully investigated, but none of them offer 
 any apparently insuperable difficulties. 
 
 Fig. 15. Brick amphoras in a large cellar in Algeria. 
 
 This form is being abandoned, on account of the difficulty 
 of making the vats strong enough when large. 
 
66 
 
 UNIVERSITY OF CALIFORNIA — EXPERIMENT STATION. 
 
 Fig. 16. Anaphoras in one of the largest and most modern cellars in Algeria. 
 
 Pig 17. Top view of the anaphoras shown in Fig. 16 
 
CALIFORNIA PUBLICATIONS AVAILABLE FOR DISTRIBUTION. 
 
 REPORTS. 
 
 1896. Report of the Viticultural Work during the seasons 1887-93, with data 
 
 regarding the Vintages of 1894-95. 
 
 1897. Resistant Vines, their Selection, Adaptation, and Grafting. Appendix to 
 
 Viticultural Report for 1896. 
 
 1898. Partial Report of Work of Agricultural Experiment Station for the years 
 
 1895-96 and 1896-97. 
 1900. Report of the Agricultural Experiment Station for the year 1897-98. 
 
 1902. Report of the Agricultural Experiment Station for 1898-1901. 
 
 1903. Report of the Agricultural Experiment Station for 1901-1903. 
 
 1904. Twenty-second Report of the Agricultural Experiment Station for 1903-1904. 
 
 BULLETINS. 
 
 Reprint. Endurance of Drought in Soils of the Arid Region. 
 
 No. 129. Report of the Condition of Olive Culture in California. 
 
 131. The Phylloxera of the Vine. 
 
 132. Feeding of Farm Animals. 
 
 133. Tolerance of Alkali by Various Cultures. 
 135. The Potato-Worm in California. 
 
 137. Pickling Ripe and Green Olives. 
 
 138. Citrus Fruit Culture. 
 
 139. Orange and Lemon Rot. 
 
 140. Lands of the Colorado Delta in Salton Basin, and Supplement. 
 
 141. Deciduous Fruits at Paso Robles. 
 
 142. Grasshoppers in California. 
 
 143. California Peach-Tree Borer. 
 
 144. The Peach-Worm. 
 
 145. The Red Spider of Citrus Trees. 
 
 146. New Methods of Grafting and Budding Vines. 
 
 147. Culture Work of the Substations. 
 
 148. Resistant Vines and their Hybrids. 
 
 149. California Sugar Industry. 
 
 150. The Value of Oak Leaves for Forage. 
 
 151. Arsenical Insecticides. 
 
 152. Fumigation Dosage. 
 
 153. Spraying with Distillates. 
 
 154. Sulfur Sprays for Red Spider. 
 
 155. Directions for Spraying for the Codling-Moth. 
 
 156. Fowl Cholera. 
 
 157. Commercial Fertilizers. 
 
 158. California Olive Oil ; its Manufacture. 
 
 159. Contribution to the Study of Fermentation. 
 
 160. The Hop Aphis. 
 
 161. Tuberculosis in Fowls. 
 
 162. Commercial Fertilizers. 
 
 163. Pear Scab. 
 
 164. Poultry Feeding and Proprietary Foods. 
 
 165. Asparagus and Asparagus Rust in California. 
 
 166. Spraying for Scale Insects. 
 
 CIRCULARS. 
 
 No. 1. Texas Fever. No. 9. Asparagus Rust. 
 
 2. Blackleg. 10. Reading Course in Economic 
 
 3. Hog Cholera. Entomology. 
 
 4. Anthrax. 11. Fumigation Practice. 
 
 5. Contagious Abortion in Cows. 12. Silk Culture. 
 
 6. Methods of Physical and Chem- 13. The Culture of the Sugar Beet. 
 
 ical Soil Analysis. 14. Practical Suggestions for Cod- 
 
 7. Remedies for Insects. ling-Moth Control in the 
 
 8. Laboratory Method of Water Pajaro Valley. 
 
 Analysis. 
 
 Copies may be had by application to the Director of the Experiment 
 Station, Berkeley, California.