UNIVERSITY OF CALIFORNIA. AGRICULTURAL EXPERIMENT STATION. BULLETIN NO. 60. Oolorimetrio Measurement of Wines. In the latest-improved instrument for this pur- pose (balleron's vino-colorimeter), this color- scale is represented by 10 little silk disks, about three-fourths of an inch in diameter, placed in a row on a pasteboard strip. Alongside of these runs a row of similar disks of white silk, and the comparison is made by viewing these white silk surfaces through a layer of the wine to be examined, which, in making the observa- tion, is made to appear exactly equal to some one of the colored silk disks, by means of a screw arrangement, which permits of making the layer of wine, placed between the eye and the white silk disks, of any required thickness, which can then be read off on a scale allowing of extremely accurate measurement. Then, recording the name of the tint, and the thickness as measured by the scale on the con- The color of red wines has always been deemed a matter of great importance by wine- makers, not so much because of any essential inherent benefit to the quality of the wine, but because of a time-honored demand for certain tints as characteristic of certain preferred brands of wine. The beauty of the ruby wine has been sung by poets on the one hand, and denounced as a device of the evil one to en- snare the unwary, on the other. On either hand, the importance of a beautiful tint in wine is admitted; and thus it becomes of prac- tical importance to determine definitely both taining cylinder, we have" all the data needed for its kind and its amount or intensity. I a permanent record of the exact color of the In France, the country pre-eminently of red wine, the intensity of which is, of course, in- wines, the art of color- blending has developed versely proportionate to the thickness of the hand in hand with that of producing definite wine-layer that has furnished the same shade qualities of wines, such as are demanded by m the comparison. customers year after year, from the annually I n order to adapt these measurements to the variable product of the vineyards. There, the current habit of using a decimal scale, most experienced purchaser of wines for blending easily understood by all, such a scale may be purposes scrutinizes carefully not only the '■ formed by dividing the number of scale di depth but also the particular tone of the wine j visions read off in the observation, into one and color, in order to obtain from their intermix- the same constant number, which represents tore just such products as his customers are 100 times the lowest reading obtained, and accustomed to. There are certain commercial which, of course, corresponds to the most in- designations, both of tint and depth of color; tensely colored wine. Thus, the latter will be but they are intelligible only to the expert, and marked 100, as the highest of the intensity vary from place to place, so that a unification scale, while all . others will fall below and of nomenclature was obviously necessary so their intensity will be expressed in percentages aoon as the greater facilities for communication of the maximum. brought these variable designations into con- The lowest reading of the scale found in this tact with each other. year's wines was .47 millimeter, or about the For some time nothing more definite than fifty-third part of an inch, in the case of measurements of intensity were thought of, toe Gros Verdot, immediately after press- and these were usually made by the simple | n g« As this is a season of deficient color, process of measuring how much water could be it was thought best to make an allow- added to a deep-tinted wine before the tint be- ance for a still deeper tint and to take .4 milli- came similar to that of a certain light- colored meter as the reading corresponding to the max- standard wine, or preferably some other solu- imum of color in a wine, so as to make all or- tion. This method involved, however, an in- dinary tints fall considerably below 100 in the superable source of error in the varying tints of percentage expression, of which the figures of wines; it being impossible to judge definitely of course express the relative depths of tint of the intensity apart from the tone of two different several wines. We find that when thus scaled, colors, in which case no two observers would few wines range in color intensity above 50 per agree as to the exact point in question. cent of the maximum. One of the most im- This difficulty led to the adoption by French portant uses of this instrument— Salleron's manufacturers, of the color-scale devised by vino colorimeter— will be in following the Chevreul, the distinguished French chemist, changes of color that our wines undergo in the n this scale the variations of each primary process of maturing. Some, as for example the color are designated by inter-combinations of krenache, lose color rapidly when left tcthem- their names for the general tints, while the selves, unblended. It is asserted that certain minor variations are marked by numbers at- blends prevent this loss of color, not only mi- tached to these. parting their own tint but preventing the depo- sition of that of the Grenache itself in the sedi- ments. It will be important to determine the correctness of this idea and the kinds of wines that will prevent the loss of color, if this can be done. Again, it will be of great importance to ascertain the effect of various modes of fermen- tation upon the tone, depth and permanency of red wines. It is asserted by some that hot fermentation tends to ultimate loss of color, while that at low temperatures tends to main- tain the original tint. It is quite certain that, according to the method of fermentation used, the extraction of the pomace and the conse- quent tint of the wine may seriously differ. All these questions, heretofore dependent main- ly upon individual estimates liable to error, can be answered with perfect definiteness by the use of this instrument. Again, when it is desired to plant or graft a vineyard with a view to making up a deficiency of color in other desirable varieties, it is of no little importance to have a definite measure of the aggregate amount of coloration that can be expected from a given number of vines of a cer- tain variety. In connection with the bearing qualities of the vines under consideration, this will form a perfectly definite guide to the proper selection. Decrease of Color after Fermentation. The subjoined table shows in a striking man- ner the changes which the colors of a number of wines, that have been observed at different times, have undergone in the course of after- fermentation. The first column of this table shows the intensity and tints observed immedi- ately after pressing, according to the scale above explained. The second column shows the number of days that have elapsed between the two readings of the colorimeter. Were these figures the same throughout, or had the readings been repeated at regular intervals (as it is intended to do hereafter), the next column would at once indicate the relative proportion of loss of color in the several wines. As it is, it becomes necessary to divide out the loss among the days of the interval, and here again we are met by the objection that the loss of color is manifestly greatest at first, and gradu- ally decreases until it becomes too slow to note at short intervals. For the present, however, we can do no better, and therefore give ^ in the fifth column the average daily loss during the period of observation, while the fourth column gives the percentage of the decrease, referring it to the original intensity taken at 100. The sixth column gives the designation of the tintB observed, according to Cbevreul's scale, which ascends through six shades of purple-red to- ward red; which then shades off toward orange in four shades. The following table shows the loss in color in red wines from the time of pressing until Nov. 20, 1886: iHliMi yiiffi oo ■ aa a B 5 85 so » P-d c : • © a . Is? j f ?22 - re a ■■ ?1 i c re ) CD CD \z-z- P o?TX!??o s?o a re" ~ =5 ccgq: cg^: 9ac: cases: a: a: B.B.B.S.' 5. r 3 • • • 2-2.' °. 2. 2. 2. ' 2. : 2. 1 ■E/E/2/2. • *° o"cTo*o"" : '• •gw ' 'S.'E.'EL'S. ' *! *2-i OS Hliw CO CS CD Oi CJi CO 00 t-' **■ CO 00 00 CO COCT^^rJrf^K-tOtCtOCOCOtO.^t-'COCOtCl-'COl-'COtO pi i . f-top! p co ro co co ! t -. o» m • CO b\ CO i^. CO ■ J-i bi H* C6 ^ co * '*> ' to *». CO CO -3 • -*J <§ to p S S£ : ^ co co co ©> ' int . m 25. CO O ^ Ox • CO W !^ CO S • CO O CO « CO In Si • »' tCbOt>StOi^C*W^h-COi— COCOt«>^I^^^^^CO►-'- , D-P-D-0-^^0-aat^c-c^&D-Q.oo^o^^p.o^&o^co^ • F 33P''«.3J• S, • ^ -a ^ T3 "a ^ 3 "C o(CA9(t(t((0((<( re re re "PL. re re re Imperfect as this table is in its present form, it gives some very striking information. Thus, the Meunier from Cupertino shows the greatest loss of color, 50.3 for the whole time since press- ing and the next to the highest daily loss, viz., 1.4 per day. This is the more remarkable, as in this case the original intensity was quite low, viz., 15.1. In most other cases of low color the loss is very slight, even where, as in the case of the Ploussard, the time between the readings haa been very long. The deepest color of all was shown by the Verdot, which during the first 17 days lost 16 per cent of the original color; but since that time has during 20 days lost nothing. During the first 19 days the Grossblaue lost over 30 per cent, while the Cabernet Franc re- mained almost stationary, as did also the Char- bono, of Gregory, daring 26 days; while the Teinturiers, in respectively 45 and 50 days, lost practically nothing at all of their color. The lat- ter, evidently, have been prized not so much for the intensity (45 per cent) as for the per- manence of their color. The Zinfandels do not appear to advantage in this table, having lost color at the rate of about 1.3 per day, during the four weeks, so that one lost fully one-third of its initial color in that time. A singular difference appears in the case of the Cabernets. In the Cabernet Franc, as above noted, the color remained stationary during 19 days; the Cabernet Sauvignon in twice that time lost 35 per cent, though still remaining slightly above the former in color; while Pftffer's Cabernet from Warm Springs, with only 16 initial color, lost 39 per cent of it at the rate of nearly 1£ per cent per day, in 31 days. Singularly enough, the same grape from Pfeffer himself, with a lower initial tint, lost nothing at all in 26 days. Such marked dis- crepancies in one and the same grape variety are well worthy of investigation, as they may lead to a better understanding of the causes of loss of color in general. Perhaps a clue to this point may be found in the comparison of the two batches of Grossblaue from Cupertino, of which one lost in 37 days only 12.5 per cent, or at the rate of one-third per cent a day; while the more mature sample, starting out at a much higher intensity, lost 30.6 per cent, or at the rate of 1.6 per day, being the max- imum loss shown in the table, for' that in- terval or any other on record. Whether the two will ultimately stop at the same point re- mains to be seen; for the present, attention may be called to the difference in their compo- sition, which is essentially, for the earlier sam- ple, a higher proportion of acid and less of tannin. That acid serves to maintain the color, has been alleged; but the present in- stance seems to furnish a striking proof of the fact, since the two differ but little in their al- coholic contents. Many other deductions which might be made from the data in the % table are omitted for the sake of brevity. The subject will be found more fully discussed in the forthcoming report of viticultural work for 1886. E. W. HlLGARD. Berkeley, Dec. 10, 1886.