arket dairying, Market Dairying BY JOHN MICHELS, B.S.A., M.S. (wisconsin) Proressor oF DairyING AND ANIMAL HusBANDRY IN THE STATE AGRICULTURAL COLLEGE oF NortH Caro.ina AUTHOR OF “‘CREAMERY BUTTER-MAKING”’ AND “DAIRY FARMING” ILLUSTRATED RALEIGH, NORTH CAROLINA PuBLISHED BY THE AUTHOR £909 ALL RIGHTS RESERVED COPYRIGHT, BY JOHN MICHELS 1909 PREFACE. Dairy instruction has hitherto been confined chiefly to the economical production of milk and the manufacture of butter and cheese. Yet those who have thoroughly studied the subject must admit that market dairying deserves fully as much attention as cither the econom- ical production of milk or the manufacture of butter or cheese. The subject of market dairying presents two very im- portant aspects: One is to educate dairymen to produce better and more wholesome milk; the other is to instruct them in all the economies relating to their business so as to insure maximum financial returns. For a number of years the author has been brought face to fate with the problems relating to market dairy- ing. He has been actively engaged in the production and marketing of sanitary milk and cream, and in the manu- facture and marketing of ice cream, cottage cheese, and skimmilk-buttermilk. The markets and dairy conditions of the country have been thoroughly investigated and new methods and plans have been developed, some of which have already been published in bulletin form or otherwise. The production of this volume is, therefore, largely the result of the knowledge and experience thus gained, and the realization of the urgent and increasing needs along this line of dairying. An attempt has been made to so arrange the material that it might answer the needs of both the classroom and the dairyman who cannot attend a dairy school. Joun MIcHELS. April 1, 1909. Chapter. ih U III. IV. Ws VI. VIL VIIL. IX. * x XII, XIII. XIV. XV. XVL XVIL XVIII. XIX. XX. XXL XXIL XXIII. XXIV. XXV. XXVI. TABLE OF CONTENTS. Page Chemical and Physical Properties of Milk........ 7 Bacteniavin: Milk <.accondae eeleainedeslieria’s ewenmieents 19 Production of Sanitary Milk.............0 0.00 eee 23 Cooling and Aeration of Milk and Cream........ 33 The Babcock Test......... Piast ait ieakad oan tananteht se 42 Creaming’ -sicxivs examinee sees eoneke cease eeeeete ss 52 Standardization of Milk and Cream.............. 59 Cold) Storage: sigicigscceintscnwesanraniina tw eacontanncss 62 How to Secure a Good Market Madidwinwes iesiomars .. 69 Retailing Milk and Cream........... ccc c ee eee eee 73 Shipping Milk and Cream.................. re 78 Washing and Sterilizing Milk Vessels............ 2 Making and Marketing Cottage Cheese............ 90 Making and Marketing Skimmilk-Buttermilk...... 08 Making and Marketing Ice Cream................ 101 Relative Market Value of Milk and its Products.. 107 Farm Buttermaking ........... 0. eee cece eee eee eee III The Dairy House........ seer eesee eee ne cece eens 129 Mechanical Refrigeration .......:. sees eee eeneeee 136 Keeping: “Accounts: .i53 ve ceeieeenignac s eawwewmangs eas 146 Pasteurizing Milk and Cream...........0..0-s eee 151 Carita We acinnezi camanudeavscnanodemmenaeea 154 The Care of Milk in the Home................-5.. 157 The Boiler and its Management...............6. /. 159 Water and Ice Supply................. eiahed es atiata als 170 Sewage Disposal from Dairy and Dwelling........ 176 Appendix sestididuaslgdacn Soham eeo ieee AA Se ds anenplNG ana glneieavees 182 Tnhdex: osscaxounedes cgonliaee ee ora wae we eeees 189 MARKET DAIRYING. CHAPTER I. CHEMICAL, AND PHYSICAL PROPERTIES OF MILK. i Milk, in a broad sense, may be defined as the normal secretion of the mammary glands of animals that suckle their young. It is the only food found in Nature con- taining all the elements necessary to sustain life. More- over it contains these elements in the proper propor- tions and in easily digestible and assimilable form. Microscopic appearance of milk showing relative size of fat globules and bacteria.—Russell’s Dairy Bacteriology. Physical Properties. Milk is a whitish opaque fluid possessing a sweetish taste and a faint odor suggestive of cows’ breath. It has an amphioteric reaction, that is, 7 8 MARKET DAIRYING it is both acid and alkaline. This double reaction is due largely to acid and alkaline salts and possibly to small quantities of organic acids. Milk has an average normal specific gravity of 1.032, with extremes rarely exceeding 1.029 and 1.033. After standing a few moments it loses its homogenous character. Evidence of this we have in the “rising of the cream.” This is due to the fact that milk is not a perfect solution but an emulsion.. All of the fat, the larger portion of the casein, and part of the ash are in suspension. In consistency. milk is slightly more viscous than water, the viscosity increasing with the decrease in temperature. It is also exceedingly sensitive to odors, possessing great absorption properties. ‘This teaches the necessity of plac- ing milk in clean pure surroundings. Chemical Composition. The composition of milk is very complex and variable, as will be seen from the fol- lowing figures: Average Composition of Normai Milk. A com- pilation of figures from various American Ex- periment Stations, Walter csdasramnemannieeheicunuancass .. 87.1% Butter fat access suaweeaws ssacoarieeses 3.9% Casein 2xieeseaxesadtawe stele deteoteue 2.9% AMUVEM, iis Racaceisici ares due aidee: Saad ca bvavalouarcuese eee 5% SURAT erscnan wind digeeseniy shin by poe Gewnne sat 4.9% ASH rasrenaigalnentaitananus cay sieaemaneues : 7%. Fibrin’. 4 svc csvoxawssawsvcasacwedeees oan Trace. Galactase ...-.-cceeees Sevaeraistalessiesacarsrnnens Trace 100.0% The great variations in the composition of milk are shown by the figures from Koenig, given below: PROPERTIES OF MILK 9 Maximum. Minimum. Wratet® ich aide tee ee 90.69 80.32 Hatt agin nay sneaatie ee yes 6.47 1.67 Case cs65 itawdaanoeee 4.23 1.79 Albumen ............... 1.44 .25 Sugar ia She es dane lece'na 6.03 2.11 ASN sauce sad enpesmeraas 1.21 -35 These figures represent quite accurately the maximum and minimum composition of milk except that the maxi- mum for fat is too low. The author has known cows to yield milk testing 7.6% fat, and records show tests even higher than this. BUTTER FAT. This is the most valuable as well as the most variable constituent of milk. It constitutes about 83% of butter and is an indispensable constituent of the many kinds of whole milk cheese now found upon the market. It also measures the commercial value of milk and cream, and is used as an index of the value of milk for butter and cheese production. Physical Properties. Butter fat is suspended in milk in the form of extremely small globules numbering about 100,000,000 per drop of milk. These globules vary con- siderably in size in any given sample, some being five times as large as ‘others. The size of the globules is -affected mostly by the period of lactation. As a rule the size decreases and the number increases with the advance of the period. In strippers’ milk the globules are some- times so small as to render an efficient separation of the cream and the churning of same impossible. The size of the fat globules also varies with different breeds. In the Jersey breed the diameter of the globule 10 MARKET DAIRYING is one eight-thousandth of an inch, in the Holstein one twelve-thousandth, while the average for all breeds is about one ten-thousandth. Night’s milk usually has smaller globules than morn- ing’s. The size of the globules also decreases with the age of the cow. The density or specific gravity of butter fat at 100° F. is .91 and is quite constant. Its melting point varies between wide limits, the average being 92° F. Composition of Butter Fat. According to Richmond, butter fat has the following composition : Butytith ccsacisaciende ance 3.85 Caprolii:cccqecsaiwe dons 3.60 + Soluble or volatile. Caprylin sou cisisewid-s's sieve -55 Caprintsccuaacisecincan » 1.90 Laurin. ssscsasveceve si - 7.40 Myristin ...........08% 20.20 | Insoluble or Palmitin ...........005 25.70 non-volatile. DLEATIN: 414s scmaemeas-s 1.80 Olein; €teie es sanemecaes 35.00 This shows butter fat to be composed of no less than nine distinct fats, which are formed by the union of glycerine with the corresponding fatty acids. Thus, buty- rin is a compound of glycerine and butyric acid; palmitin, a compound of glycerine and palmitic acid,’ etc. The most important of these acids are palmitic, oleic, and butyric. Palmitic acid is insoluble, melts at 144° F., and forms (with stearic acid) the basis of hard fats. Oleic acid is insoluble, melts at 57” F., and forms the basis of soft fats. PROPERTIES OF MILK 11 Butyric acid is soluble and is a liquid which solidifies at —2° F. and melts again at 28° F. Insoluble Fats. A study of these fats is essential in elucidating the variability of the churning temperature of cream. As a rule this is largely determined by the relative amounts of hard and soft fats present in butter fat. Other conditions the same, the harder the fat the higher the churning temperature. Scarcely any two milks contain exactly the same relative amounts of hard and soft fats, and it is for this reason that the churning tem- perature is such a variable one. The relative amounts of hard and soft fats are influ- enced by: 1. Breeds. 2. Feeds. 3. Period of lactation, 4. Individuality of cows. The butter fat of Jerseys is harder than that of Hol- steins and, therefore, requires a relatively high churning temperature, the difference being about six degrees. Feeds have an important influence upon the character of the butter fat. Cotton seed meal and bran, for example, materially increase the percentage of hard fats. Gluten feeds and linseed meal, on the other hand, produce a soft butter fat. With the advance of the period of lactation the per- centage of hard fat increases. This chemical change; to- gether with the physical change which butter fat under- goes, makes churning difficult in the late period of lac- tation. The individuality of the cow also to a great extent influences the character of the butter fat. It is inherent 12 MARKET DAIRYING in some cows to produce a soft butter fat, in others to produce a hard butter fat, even in cows of the same breed. Soluble Fats. The soluble or volatile fats, of which butyrin is the most important, give milk and sweet cream butter their characteristic flavors. Butyrin is found only in butter fat and distinguishes this from all vegetable and other animal fats. The percentage of soluble fats decreases with the period of lactation, also with the feeding of dry feeds and those rich in protein. Succulent feeds and those rich in carbo- hydrates, according to experiments made in Holland and elsewhere, increase the percentage of soluble fats. This may partly account for the superiority of the flavor of June butter. It may be proper, also, to discuss under volatile or _ soluble fats those abnormal flavors that are imparted to milk, cream, and butter by weeds like garlic and wild onions, and by various feeds such as beet tops, rape, par- tially spoiled silage, etc. These flavors are undoubtedly due to abnormal volatile fats. Cows should never be fed strong flavored feeds shortly before milking. When this is done the odors are sure to be transmitted to the milk and the products therefrom. When, however, feeds of this kind are fed shortly after milking no bad effects will be noticed at the next milking. Albumenoids. These are nitrogenous compounds which give milk its high dietetic value. Casein, albumen, globulin, and nuclein form the albumenoids of milk, the casein and albumen being by far the most important. Casein. This is a white colloidal substance, possessing neither taste nor smell. It is the most important tissue- forming constituent of milk and forms the basis of an almost endless variety of cheese. PROPERTIES OF MILK 13 The larger portion of the casein is suspended in milk in an extremely finely divided amorphus condition. It is intimately associated with the insoluble calcium phosphate of milk and possibly held in chemical combination with this. Its study preserits many difficulties, which leaves its exact composition still undetermined. Casein is easily precipitated by means of rennet extract and dilute acids, but the resulting precipitates are not identically the same. It is not coagulated by heat. Albumen. In composition albumen very closely re- sembles casein, differing from this only in not containing sulphur. It is soluble and unaffected by rennet, which causes most of it to pass into the whey in the manufacture of cheese. It is coagulated at a temperature of 170° F. It is in their behavior toward heat and rennet that casein and albumen radically differ. Milk Sugar. This sugar, commonly called lactose, has the same chemical composition as cane sugar, differing from it chiefly in possessing only a faint sweetish taste. It readily changes into lactic acid when acted upon by the lactic acid bacteria. This causes the ordinary phenom- enon of milk souring. The maximum amount of acid in milk rarely exceeds .g%, the germs usually being checked or killed before this amount is formed. There is there- fore always a large portion of the sugar left in sour milk. All of the milk sugar is in solution. Ash. Most of the ash of milk exists in solution. It is composed of lime, magnesia, potash, soda, phosphoric acid, chlorine, and iron, the soluble lime being the most important constituent. It is upon this that the action of rennet extract is dependent. For when milk is heated to high temperatures the soluble lime is rendered insoluble and rennet will no longer curdle milk. It seems also that 14 MARKET DAIRYING the viscosity of milk and cream is largely due to soluble lime salts. Cream heated to high temperatures loses its viscosity to such an extent that it can not be made to “whip.” Treatment with soluble lime restores its orig- inal viscosity. The ash is the least variable constituent of milk. Colostrum Milk. This is the first milk drawn after parturition. It is characterized by its peculiar odor, yel- low color, broken down cells, and high content of albu- men which gives it its viscous, slimy appearance and causes it to coagulate on application of heat. According to Eugling the average composition of colos- trum milk is as follows: Water Uo xicitensviesavenesiewsant es see 71.69% Pat icacieguens- Sa seae eda slacukie 44 veel 3.37 CASEI: Src ein see satiate htend & eae acepraces 4.83 Albumen agvicsa vivvndios s yeas Saenees 15.85 USAT sisiieidielvid ies sre ateidaaherc ae s o5-s.ccnaveiee 2.48 ASH Sicetouii shes eacecun ee eoeeees 1.78 The secretion of colostrum milk is of very short dura- tion. Usually within four or five days after calving it assumes all the properties of normal milk. In some cases, however, it does not become normal till the sixth or even the tenth day, depending largely upon the condition of the animal. A good criterion in the detection of colostrum milk is its peculiar color, odor, and slimy appearance. The dis- appearance of these characteristics determines its fitness for butter production. Milk Secretion. Just how all of the different con- stituents of milk are secreted is not yet definitely understood. But it is known that the secretion takes PROPERTIES OF MILK 15 place in the udder of the cow, and principally during the process of milking. Further, the entire process of milk elaboration seems to be under the control of the nervous ‘system of the cow. This accounts for the changes in flow and richness of milk whenever cows are subjected to abnormal treatment. It is well known that a change of milkers, the use of rough language, or the abuse of ‘cows with dogs and milk stools, seriously affects the production of milk and butter fat. It is therefore of the greatest practical importance to milk producers to treat cows as gently as possible, especially during the process of milking. How Secreted. The source from which the milk con- stituents are elaborated is the blood. It must not be sup- posed, however, that all the different constituents already exist in the blood in the form in which we find them in milk, for the blood is practically free from fat, casein, and milk sugar. ‘These substances must then be formed in the cells of the udder from material supplied them by the blood. Thus there are in the udder cells that have the power of secreting fat in a manner similar to that by which the gastric juice is secreted in the stomach. Simi- larly, the formation of lactose is the result of the action of another set of cells whose function is to produce lac- tose. It is believed that the casein is formed from the albumen through the activity of certain other cells. The water, albumen, and soluble ash probably pass directly ‘from the blood into the milk ducts by the process known as osmosis. Variations in the Quality of Milk. Milk from dif- ferent sources may vary considerably in composition, particularly in the percentage of butter fat. Even the 16 MARKET DAIRYING milk from the same cow may vary a great deal in compo- sition. ‘The causes of these variations may be assigned to two sets of conditions: I.—Those natural to the cow. II.—Those of an artificial nature. I. QUALITY OF MILK AS AFFECTED BY NATURAL CONDI- TIONS. 1. The composition of the milk of all cows undergoes a change with the advance of the period of lactation. During the first five months the composition remains prac- tically the same. After this, however, the milk becomes gradually richer until the cow “dries up.” The following figures from Van Slyke illustrate this change: Month of Per cent of fat lactation. in milk. Tissues vba dul tap Cab ca vedente faceted poor 4.54 2 iasiowhids etonnivagtaics si miaushar ans Creat 4.33 Begeiacasesuseedacneyes Reoawe teense 4.28 Bes cnss tee ca hedigicuisten spits Son pie t piiaes ES SEE NE 4.39 SB avenge eecn vac IRR NO neared pda TG 4.38 One ate care e ener oonneee 4.53 Pegi vasa nPremsbs hier aie tonne eae aides seinen 4.56 Ssontsnuswnebavenrieneds seks Meee eS 4.66 shes suc nstaaa os eee ata ee sees ate 4.79 Ole assguaus digi deeulkede ins Salen eahewaaehos 5.00 It will be noticed from these figures that the milk actually decreases somewhat in richness during the first three months of the period. But just before the cow dries up, it may test as high as 8%. 2. The quality of milk also differs with different breeds. Yet breed differences are less marked than those of the individual cows of any particular breed. Some breeds produce rich milk, others relatively poor PROPERTIES OF MILK 17 milk. The following data obtained at the New Jersey Experiment Station illustrates these differences: Total Milk Breed. Solids. Fat. Sugar. Proteids.| Ash. Per cent.|Per cent./Per cent./Per cent./Per cent. Ayshire........ 12.70 3.68 4.84 3.48 -69 Guernsey ...... 14.48 5.02 4.80 3.92 ay ts) Holstein....... 12.12 3.51 4.69 3.28 64 Jersey.......... 14.34 4.78 4.85 3.96 15 3. Extremes in the composition of milk are usually to be ascribed to the individuality or ‘make up” of the cow. It is inherent in some cows to produce rich milk, in others to produce poor milk. In other words, Nature has made every cow to produce milk of a given richness, which can not be perceptibly changed except by careful selection and breeding for a number of generations. II. QUALITY OF MILK AS AFFECTED BY ARTIFICIAL CON- DITIONS. 1. When cows are only partially milked they yield poorer milk than when milked clean. This is largely explained by the fact that the first drawn milk is always poorer in fat than that drawn last. Fore milk may test as low as .8%, while the strippings sometimes test as high as 14%. 2. Fast milking increases both the quality and the quantity of the milk. It is for this reason that fast milkers are so much preferred to slow ones. , ; ; 18 MARKET DAIRYING 3. The richness of milk is also influenced by the length of time that elapses between the milkings. In general, the shorter the time between the milkings the richer the milk. This, no doubt, in a large measure accounts for the differences we often find in the richness of morning’s and night’s milk. Sometimes the morning’s milk is the richer, at other times the evening’s, depending largely upon the time of day the cows are milked. Mulk can not, however, be permanently enriched by milking three times instead of twice a day. 4. Unusual excitement of any kind reduces the quality of milk. The person who abuses cows by dogs, milk stools, or boisterousness, pays dearly for it in a reduction of both the quality and the quantity of milk produced. 5. Starvation also seriously affects both the quality and the quantity of milk: It has been repeatedly shown, in this country and in Europe, that under-feeding to any great extent results in the production of milk poor in fat. 6. Sudden changes of feed may slightly affect the richness of milk, but only temporarily. So long as cows are fed a full ration, it is not possible to change the richness of milk permanently, no matter what the character of feed composing the ration. 7. Irregularities of feeding and milking, exposure to heat, cold, rain, and flies, tend to reduce both the quantity and the quality of milk produced. CHAPTER II. BACTERIA IN MILK. The term bacteria is applied to the smallest of living plants, which can be seen only under the highest powers of the miscroscope. Each bacterium is made up of a single cell. These plants are so small that it would require 30,000 of them laid side by side to measure an inch. Their presence is almost universal, being found in the air, water, and soil; in cold, hot, and temperate climates; and in living and dead as well as inorganic matter. Bacteria grow with marvelous rapidity. A single bac- terium is capable of reproducing itself a million times in twenty-four hours. They reproduce either by a simple division of the mother cell, thus producing two new cells, or by spore formation in which case the contents of the mother cell are formed into a round mass called a spore. These spores have the power of withstanding unfavorable conditions to a remarkable extent, some being able to endure a temperature of 212° F. for several hours. Most bacteria require for best growth a moist, warm, and nutritious medium such as is furnished by milk, in which an exceedingly varied and active life is possible. © In nature and in many of the arts and industries, bacteria are of the greatest utility, if not indispensable. They play a most important part in the disintegration of vegetable and animal matter, resolving compounds into their elemental constituents in which form they can again 19 20 MARKET DAIRYING be built up and used as plant food. In the art of butter and cheese making bacteria are indispensable. The to- bacco, tanning, and a host of other industries cannot flourish without them. Lactic Acid Bacteria; In milk and cream intended for direct consumption, bacteria of any kind are enemies to dairymen. The class of bacteria that is feared more than any other, -perhaps, is that which causes milk to sour. The organisms belonging to this class are known as lactic acid bacteria. They are non-spore bearing and grow best at a temperature of from go° to 98° F. At 40° F, their growth ceases; exposed to a temperature of 140° for 15 minutes they are killed. The souring of milk and cream is due to the action of the lactic acid bacteria upon the milk sugar changing it into lactic acid. Acid is therefore always produced at the expense of milk sugar. But the sugar is never all converted into acid because the production of acid is limited. When the acidity reaches about .9% the lactic acid bacteria are either checked or killed and the pro- duction of acid ceases. Owing to the universal presence of these bacteria it is almost impossible to secure milk free from them. Under cleanly conditions the lactic acid type of bacteria always predominates in milk. When, however, milk is drawn under uncleanly conditions the lactic organisms may be outnumbered by other species of bacteria which give rise to the numerous taints often met with in milk. While the acid bacteria are objectionable in milk in- tended for direct consumption, in cream made into butter they are indispensable. The highly desirable aroma in butter is the result of the growth of these organisms in the process of cream ripening. There are a number of BACTERIA IN MILK 21 different species of bacteria that have the power of pro- ducing lactic acid. Milk containing only lactic acid bac- teria is spoken of as a “pure culture” or “starter.” Such cultures are now a commercial product and should be used wherever. fancy butter and cheese and sour milk products are desired. The method of using these pure cultures or starters is discussed in the chapter on cottage -cheese making, page 90. Bacteria that Produce Taints and Bad Odors. While the lactic are the commonest bacteria of milk, there are always present many other types, some of which produce serious taints and bad odors. Bacteria of this kind are usually associated with filth, and dairies that be- come strongly infected with them show lack of cleanliness in the care and handling of the milk. The commonest bad flavors produced by this class of bacteria may be designated as rancid, bitter, strong, gassy, oily, fishy, and putrefactive. In market milk these filth bacteria are objectionable not only because of the bad flavors they produce, but also because they are recognized as a common cause of infantile troubles, such as diarrhcea. The high mortality among bottle-fed babies has been shown to be largely due to drinking milk that has been produced under unsanitary conditions. Disease Producing Bacteria. Milk frequently be- comes infected with this class of bacteria through diseased cows, infected water, infected milk vessels, and diseased attendants. One of the commonest of the disease producing bacteria is the bacillus tuberculosis, This germ usually finds entrance into the milk in two ways: It may come from the cow directly through her milk, or it may gain access to the milk through the litter in the barn. No milk should 22 MARKET DAIRYING be offered for sale except that produced from cows that have been shown to be free from tuberculosis by ‘the tuberculin test. A common means of infecting milk is through the water used in the dairy. Many typhoid fever epidemics have been positively traced to milk infected with typhoid or- ganisms through the water supply. The purity of the water used in a dairy should be absolutely above sus- picion. Another means of spreading. disease through milk is the milk bottle. Every dairyman will, at some time, have customers in whose families there is sickness, and bottles passing unsterilized from such homes to healthy ones, are often the means of communicating the disease to the latter. Many instances of this kind are on record. ‘The absolute necessity of sterilizing the milk bottles to pre- vent the spread of contagious diseases is too evident to require further discussion. Milkers and attendants who come in contact with per- sons suffering from contagious diseases, or who may themselves be afflicted with disease, should be rigidly excluded from the dairy. Over five hundred epidemics of various diseases, such as scarlet fever, diphtheria, typhoid fever, etc., have been directly traced to infected milk. . With the large number of bacteria ordinarily found in milk and with the great variety of pathogenic organisms that are often disseminated by means of it, it behooves us to know under what conditions milk should be pro- duced and handled to reduce bacterial contamination to a minimum. These conditions will be discussed in the following chapter. CHAPTER III. SANITARY MILK PRODUCTION. Sanitary Milk Defined. Sanitary milk is milk from healthy cows, produced and handled under conditions in which contamination from filth, bad odors, and bacteria, is reduced to a minimum. Importance of Sanitary Milk. The production of clean milk is one of the most important subjects that con- fronts the American dairyman at the present time. Fur- ther improvement in the quality of butter and cheese must largely be sought in the use of cleaner milk. With the better appreciation by the public of the great nutritive value of milk, there opens an unlimited market for it for consumption in the raw form. Already we find that milk produced under the best sanitary conditions sells for prac- tically double that obtained under ordinary, more or less, slip-shod conditions. So great is the clamor for cleaner milk that any extra efforts expended in producing it are certain to be richly compensated. The Necessary Conditions for the production of sani- tary milk are as follows: (1) Healthy cows; (2) sani- tary barn; (3) clean barn yard; (4) clean cows; (5). clean milkers; (6) clean milk vessels; (7) clean, whole- some feed; (8) pure water; (9) clean strainers; (10) dust-free stable air; (11) clean bedding; (12) milking with dry hands; (13) thorough cooling of milk after milking; (14) sanitary milk room. Healthy Cows. The health of the cow is of prime im- portance in the production of sanitary milk. All milk 23 24 MARKI:T DAIRYING from cows affected with contagious diseases should be rigidly excluded from the dairy. Aside from the general unfitness of such milk there is danger of the disease pro- ducing organisms getting into the milk. It has been found, for example, that cows whose udders are affected with tuberculosis, yield milk containing these organisms. The prevalence of this disease among cows at present makes it imperative to determine definitely whether or not cows are affected with the disease, by the application of the tuberculin test. Any feverish condition of the cow tends to impart a feverish odor to the milk, which should therefore not be used. Especially important is it that milk from diseased udders, no matter what the character of the disease, be discarded. Sanitary Barn. Light, ventilation, and ease of clean- ing are essential to a sanitary dairy barn. The disinfect- ant action of an abundance of sunlight, secured by pro- viding a large number of windows, is of the highest im- portance. Of equal importance is a clean, pure atmosphere, secur- ed by a continuous ventilating system. ‘The fact that odors of any description are absorbed by milk with great avidity, sufficiently emphasises the great need of pure air. To permit of easy cleaning, the barn floors and gutters should be built of concrete. They should be scrubbed daily, and care should be taken to keep the walls and ‘ceiling free from dust and cobwebs. The feed boxes must also be cleaned after each feed. The stalls should be of the simplest construction, to afford as little chance for lodgement of dust as possible. l‘urthermore, they should so fit the cows as to cause the latter to stand with their hind feet on the edge of the gut- SANITARY MILK PRODUCTION 25 ter, a matter of the highest importance in keeping cows clean. The walls and ceiling should be as smooth as possible. Moreover, they should be frequently disinfected by means of a coat of whitewash. The latter gives the barn a striking sanitary appearance. Clean Barn Yard. A clean, well drained barn yard is an essential factor in the production of sanitary milk. Where cows are obliged to wade in mire and filth, it is easy to foretell what the quality of the milk will be. To secure a good barn yard it must be covered with gravel or cinders, and should slope away from the barn. If the manure is not taken directly from the stable to the fields, it should be placed where the cows cannot have access ° to it. Clean Cows. Where the barn and barn-yard are sani- tary, cows may be expected to be reasonably clean. Yet cows that are apparently clean, may still be the means of infecting milk to no small degree. When we consider that every dust particle and every hair that drops into the milk may add hundreds, thousands, or even millions of bacteria to it, we realize the importance of taking every precaution to guard against contamination from this source, To keep cows as free as possible from loose hair and dust particles they should be carded and brushed regu- larly once a day. ‘This should be done after milking to avoid dust. Five to ten minutes before the cow is milked her udder and flanks should be gently washed with clean, tepid water, by using a clean sponge or cloth. This will allow sufficient time for any adhering drops of water to drip off, at the same time it will keep the udder and flanks sufficiently moist to prevent dislodgment of dust particles 26 MARKET DAIRYING and hairs at milking time. This practically means that the milker must always have one or two cows washed ahead. He should be careful to wash his hands in clean water after each washing. Under ordinary conditions the cow is the greatest source of milk contamination. The rubbing of the milker against her and the shaking of the udder will dislodge numerous dust particles and hairs unless the foregoing instructions are rigidly followed. Attention should also be given to the cow’s switch, which should be kept scrupulously clean. The usual switching during milking is no small matter in the con- tamination of milk when the switch is not clean. Clean Milkers. Clothes which have been worn in the fields are not suitable for milking purposes. Every milker should be provided with a clean, white milking suit, con- sisting of cap, jacket and trousers. Such clothes can be bought ready made for one dollar; and, if frequently laundered, will materially aid in securing clean milk. 4 Fig. 1. Unflushed seam. Fig. 2. Flushed seam. Milkers should also wash and dry their hands before milking, and, above all, should keep them dry during milking, Clean Vessels. All utensils used in the handling of SANITARY MILK PRODUCTION 27 milk should be made of good tin, with as few seams as possible. Wherever seams occur, they should be flushed with solder. Unflushed seams are difficult to clean, and, as a rule, afford good breeding places for bacteria. Fig. 1 illustrates the character of the unflushed seam; Fig. 2 shows a flushed seam, which fully illustrates its value. Fig. 3 illustrates a modern sanitary milk pail. The value of a partially closed pail is evident from the re- duced opening, which serves to keep out many of the micro-organisms that otherwise drop into the pail during Fig. 3. Sanitary Milk Pail. milking. While such a pail is somewhat more difficult to clean than the ordinary open pail, it is believed that the reduced contamination during milking far outweighs this disadvantage. All utensils used in the handling of milk should be as nearly sterile as possible. A very désirable method of cleaning them is as follows: First, rinse with warm or cold water. Second, scrub \ 28 MARKET DAIRYING with moderately hot water containing some sal soda. The washing should be done with brushes rather than cloth because the bristles enter into any crevices present which the cloth cannot possibly reach. Furthermore, it is very difficult to keep the cloth clean. Third, scald thoroughly with steam or hot water, after rinsing out the water in which the sal soda was used. After scalding, the utensils should be inverted on the shelves without wiping and allowed to remain in this place until ready to use. This will leave the vessels in a practically sterile condition. Fourth, if it is possible to turn the inside of the vessels to the sun, in a place where there is no dust, then it is desirable to expose the utensils during the day to the strong germicidal action of the direct sun’s rays. Clean, Wholesome Feed. Highly fermented and aromated feeds, like sour brewers grains and leeks should be rigidly withheld from dairy cows when anything like good flavored milk is sought. So readily does milk absorb the odors of feeds through the system of the ani- mal, that even good corn silage, when fed just previous to milking, will leave its odor in the milk. When fed after milking, however, no objection whatever can be raised against corn silage because not a trace of its odors is then found in the milk. Aromatic feeds of any kind should always be fed after milking. Pure Water. Since feeds are known to transmit their odors to the milk through the cow, it is reasonable to ex- pect water to do the same. Cows should, therefore, never be permitted to drink anything but pure, clean-flavored water. The need of pure water is further evident from the fact that it enters so largely into the composition of milk. SANITARY MILK PRODUCTION 29 The water of ponds and stagnant streams is especially dangerous. Not only is such water injurious to the health of cows, but in wading into it, they become contaminated with numerous undesirable bacteria, some of which may later find their way into the milk. Strainers and Straining. Milk should be drawn so clean as to make it almost unnecessary to strain it. This operation is frequently done under the delusion that so long as it removes all visible dirt the milk has been entirely purified. The real harm, however, that comes from hairs and dust particles dropping into the milk is not so much in the hairs and dust particles themselves as in the millions of bacteria which they carry with them. These bacteria are so small that no method of straining will remove them. Straining can not even remove all of the dirt, because some of it will go in solution. A good strainer consists of two thicknesses of cheese cloth with a layer of absorbent cotton between. The strainer is to be placed on the can or vat into which the milk is to be strained and not on the milk pail. While a strainer like the above placed upon the milk pail, reduces the bacterial content slightly in the hands of careful milk- ers, it is believed that the slight advantage gained would be more than off-set by greater carelessness in milking; especially might this be true with ignorant milkers who are apt to think that the strainer will make up for any carelessness on their part. A cheese cloth strainer on the milk pail is worse than useless with any kind of milker, New sterilized cotton must be used at each milking and the cloths must be thoroughly washed and sterilized. Like the cotton, it is best to use the cloth but once. Dust-Free Air: Great precaution should be taken not 30 MARKET DAIRYING to create any dust in the stable about milking time, for this is certain to find its way into the milk. Cows should, therefore, never be bedded or receive any dusty feed just before or during milking. Dry roughage, such as hay and corn fodder, always contains a considerable amount of dust, and when fed before or during milking may so charge the air with dust as to make clean milk an impossibility. Moistening the floor and walls with clean water pre- vious to milking materially minimizes the danger of get- ting dust into the milk. A mistake not infrequently made even in the better class of dairies is to card and brush the cows just before milking. While this results in cleaner cows, the advantage thus gained is far more than off- set by the dirtier air, which, as will be shown later, materially increases the germ content of the milk. The carding and brushing should be done at least thirty min- utes before the milking commences. Clean Bedding. Clean shavings and clean cut straw should preferably be used for bedding. Cows stepping and lying on dirty bedding will soil themselves and create a dusty barn air. Milking With Dry Hands. A _ prolific source of milk contamination is the milking with wet hands. Where the milker wets his hands with milk, some of it is bound to drip into the pail, carrying with it thousands or mil- lions of bacteria, depending upon the degree of cleanliness of the milker’s hands and the cow’s udder. There is no excuse for the filthy practice of wet milking, since it is just as easy to milk with dry hands. Fore-Milk. Where the purest milk is sought, it is de- sirable to reject the first stream or two from each teat, as this contains many thousands of bacteria. The reason SANITARY MILK PRODUCTION 31 for this rich development of germs is found in the favor- able conditions provided by the milk in the milk-ducts of the teats, to which the bacteria find ready access. Flies. Flies not only constitute a prolific but also a dangerous source of milk contamination. These pests visit places of the worst description and their presence in a dairy suggests a disregard for cleanliness. Of 414 flies examined by the Bacteriologist of the Connecticut Station, the average number of bacteria carried per fly was one and a quartcr millions. Flies should be rigidly excluded from all places where they are apt to come in contact with the milk. Experimental Data. To show to what extent the bacterial content of milk may be reduced by adopting the precautions suggested in the foregoing pages, a few experimental data are herewith presented. In Bulletin No. 42 of the Storrs (Conn.) Experiment Station, Stocking reports the following: 1. When the cows were milked before feeding the number of bacteria per c. c. was 1,233; when milked im- mediately after feeding, the number of bacteria was 3,656, or three times as many. 2. When the udder and flanks of the cows were wiped with a damp cloth, the number of bacteria per c. c. was 716; when not wiped the number was 7,058, or ten times as great. 3. When the cows were not brushed just before milk- ing the number of bacteria per c. c. was 1,207; when brushed just before milking, the number was 2,286, or nearly twice as great. 4. When students who had studied the production of clean milk did the milking, the number of bacteria per c. c. was 914; when the milking was done by regular wie MARKET DAIRYING unskilled milkers the number of bacteria was 2,846, or three times as great. Wiping or washing udders before milking not only very materially reduces the bacterial content of the milk, but also lessens the amount of dirt to a very great extent. Frazer has shown that “the average weight of dirt which falls from muddy udders during milking is ninety times as great as that which falls from the same udder after washing, and when the udder is slightly soiled it is eighteen times as great.” Clean Milking. (From Da. Div., U.S. Dept. of A.) CHAPTER IV. COOLING AND AERATION OF MILK AND CREAM, Importance of Low Temperature. Milk always con- tains bacteria no matter how cleanly the conditions under which it is drawn. At ordinary temperatures these bac- teria increase with marvelous rapidity; at low tempera- tures their growth practically ceases. The effect of tem- perature on bacterial development is graphically shown in Fig. 4. NA AWW y UU Se Fig. 4.—Relation of temperature to bacterial growth. @ represents a single bacterium; 6, its progeny in twenty- -four hours in inilk kept at 50° F.;c, its progeny in twenty- -four hours in milk kept at 70° F. (Bul. 26, Storrs, Conn.) At a temperature of 50° F. the bacteria multiplied five times; at 70° F. they multiplied seven hundred and fifty times, Roughly speaking, at 98° F. bacteria multiply one hun- $ 33. 34 MARKET DAIRYING dred times faster than at 70° F. At 32° F. bacterial de- velopment practically ceases. Milk or cream may be kept sweet a long time at 40° to 45° F. because the lactic acid bacteria practically stop growing at these temperatures. But there are other classes of bacteria that can grow at these temperatures, as evidenced by the production of undesirable flavors. Such flavors usually become noticeable after thirty-six hours. Where milk and cream are to be kept in the best possible condition, it is necessary to reduce the tempera- ture to within a few degrees of freezing. Lack of thorough cooling necessitates two deliveries of milk per day, and, what is still’ worse, requires many dairymen to milk their cows shortly after midnight and shortly after midday, a drudgery which casts a damper upon the whole milk business. Lack of cooling also means financial loss through souring of milk and leads to many dissatisfied customers. Prompt Cooling. Milk should be cooled as quickly as possible after it is drawn. Indeed, the milk should be taken directly from the cow to the cooling room and promptly cooled. To do this conveniently it is necessary to have the cooling room located as near the barn as is consistent with freedom from barn odors. Too often the milk is allowed to remain in the barn until all the cows have been milked, and this may require from two to three hours, depending upon the number of cows milked by each milker. A few hours delay in cooling reduces the keeping quality of milk to a far greater extent than is commonly supposed. Importance of Aeration. Milk not only con- tains bacteria immediately after it is drawn, but it also contains gases, chief among which, perhaps, is car- COOLING AND AERATION 35 bonic acid gas. .These gases should be removed as quickly as possible after milking by exposing the milk in thin sheets to the atmosphere. Fortunately the construction of modern coolers is such as to make it possible to do the cooling and aerating in one operation. Formerly it was customary for dairymen to aerate their milk before cooling. Such practice is known to give somewhat better aeration than is possible where the cool- ing and aerating are performed in the same operation; yet the difference is so slight that consumers cannot detect it. The practice of aerating first and cooling afterward is therefore being abandoned. Coolers. All modern coolers permit cooling with ice water. Without this a sufficiently low temperature can- not be obtained to stop practically all bacterial growth. To meet the requirements of dairies of different sizes, sev- eral styles of coolers are herewith described and itflus- trated. Corrugated Cooler. This style of cooler is shown in Fig. 5, which also shows a desirable method of fastening it. It is especially adapted to dairies having from fifteen to thirty cows. The cooler consists of two parts: An upper section which is used to cool milk and cream with uniced water, and a lower section through which ice water is circulated. A storage tank for well water may be placed above the ceiling. From this the water'is admitted to the upper section through the valve which is used to regulate the flow. As shown by the arrows the water enters the section at the bottom and discharges at the top. The waste water may be conducted to the feéd water tank of the boiler, to a watering trough, or other places where it may be useful. 36 MARKET DAIRYING ‘ Mitk RESERVOIR Wei WATER C COLED SECTION Tce WATER CooLepSEcTion Pune s) FLooR Fig. 5.—Showing Corrugated Cooler and Method of Support. By means of the pump at the left, the ice water is forced back into the small tank at the right, which con- tains finely crushed ice. COOLING AND AERATION 37 As might be expected, by forcing the ice water from the cooler back into the ice water storage, a considerable saving is effected, not only of ice and water, but of time as well. Proof of these advantages is brought out by the results recorded in the following table, which shows the work of the cooler with and without the ice water pump. When no pump was used, ‘ordinary well water was sprayed over finely crushed ice in the can shown at the right, and the discharge was allowed to run into the drain. Taste SHowrnc Work oF Cooter With AND WIrrHouT THE Pump. Tempera- T empera- Amount | Time in are ee ture of Number of Experiment. [Ice Used—| Cooling— fore Cool- | Well Wa- 7 Pounds.. | Minutes, ing—De- | tet—De- grees F, grees F, With pump.-.---_. 37 45 85 3 No. 1 Without pump..... 89 92 88 3 With pump .~...... 35 40 85 66 No. 2 Without puimp---.- 94 82 84 66 No. 3 Without pump..-..- 85 93 8 64 With pump 38 45 88 72 No. 4 Without pump..... 95 85 85 72 With pump -~...-.. 34 43 85 70 No. 5 Without pump..... 83 88 88 70 With pump........ 35 41 85 49 Average pie men | =f | a Without pump..... 89 88 86 69 38 MARKET DAIRYING. All the milk was cooled to 45° F., and the amount of milk cooled in each experiment was forty-four gallons, one-half of which was cooled with a pump and the other half without. The above figures show that less than half the amount of ice and less than half as much time were required in cooling with the pump than when no pump was used. Where no ice is intended to be used, coolers may be purchased without the ice water section. GPRING WATER | ING WE DISCHARGE [ff my SPRING WATER SUPPLY ssa (7 IcE WATER | Berg 9 SUPPLY Fig. 6.—Tubular Cooler. The cooler is fastened by means of two-inch gal- vanized iron gas pipes, the lower ends of which are em- bedded in the concrete floor while the upper ends are at- COOLING AND AERATION 39 tached to the ceiling (Fig. 5). The milk reservoir is also supported by galvanized iron gas pipes, in the manner shown in the illustration. The water pump should be fastened to the concrete floor in a manner similar to that in which the cream separator is fastened (see page 57). Tubular Cooler. Fig. 6 illustrates this type of cooler, which is recommended for dairymen having thirty or more cows. This cooler is very substantial, and, as a rule, has greater width in proportion to length than the corrugated style, which leaves the top of the cooler a more convenient distance from the floor. It may be fastened and operated in the same manner as the corru- gated cooler shown in Fig. 5. Cone-Shaped Cooler. For dairies having fewer than fifteen cows a cheap cooler like that shown in Fig. 7 may be used to advantage. The water enters the bottom of the cooler and discharges at the top, while the milk flows in a thin sheet over the outside. Ice may be placed inside the cooler, if desired. The can at the top is the milk re- Fig. 7.Cone Shaped Cooler. ceiver, which has small openings ‘at the bottom near the outside, through which the milk discharges in fine streams, directly upon the cone below. Cooling With Brine. This is the cleanest, most con- 40 MARKET DAIRYING venient and efficient, and, in many cases, the cheapest method of cooling milk and cream. The brine may be reduced to any temperature desired with a mechanical | refrigerating machine. It is forced through the cooler with a pump, in the same manner as ordinary ice water. With the latter it is difficult to cool milk and cream below 40° F., while with the brine the temperature is easily re- duced to 34° F., at which milk-and cream remain prac- tically without change. Such a low temperature is espe- cially desirable in shipping milk and cream. When cream leaves the dairy at a temperature near freezing, it may be shipped*in an ordinary can wrapped with a felt jacket a distance of 500 miles or more in warm weather without undergoing a noticeable change in either flavor or acidity. Precautions in Cooling. | While cooling milk or cream, the room should be kept damp, especially the floor. This will keep down any dust that may be in-the room and thus keep it from getting into the milk. Draughts should be avoided during cooling for the same reason. In this connection it is well to remember that the real harm is not so much in the dust particles them- selves as in the many bacteria which usually adhere to them. Where coolers are left exposed to the air of the room after they have been cleaned and sterilized, they should be rinsed off with boiling water just before using. It is important also to use a reliable thermometer. Ordinary cheap thermometers often read two to six de- grees too high or too low. A standard thermometer should be on hand, by which the cheaper ones may be standardized. Never Use Ice in Milk or Cream. Adding ice di- rectly to milk and cream is a pernicious, though not un- COOLING AND AERATION 41 common, practice. The best of natural-ice contains dirt and bacteria. Even ice made by mechanical means from distilled water often contains considerable quantities of impurities. Ice also is an adulterant just as much as water. In case of cream cooled with ice the body is un- satisfactory, even if the cream contains the required amount of fat. . CHAPTER V. THE BABCOCK TEST. This is a cheap and simple device for determining the percentage of fat in milk, cream, skim-milk, buttermilk, whey, and cheese. It was invented in 1890 by Dr. S. M. Babcock, of the Wisconsin Agricultural Experiment Sta- tion, and ranks among the leading agricultural inventions of modern times. The chief uses of the Babcock test may be mentioned as follows: 1. It has made possible the payment for milk accord- ing to its quality. 2. It has enabled butter and cheese makers to detect undue losses in the process of manufacture. 3. It has made possible the grading up of dairy herds by locating the poor cows. 4. It has, in a large measure, done away with the prac- tice of watering and skimming milk. Principle of the Babcock Test. The separation of the butter fat from milk with the Babcock test is made - possible: ‘ 1. By the difference between the specific gravity of butter fat and milk serum. 2. By the centrifugal force generated in the tester. 3. By burning the solids not fat with a strong acid. Sample for a Test. Whatever the sample to be tested, always eighteen grams are used for a test. In testing cream and cheese, the sample is weighed. For testing milk, skim-milk, buttermilk, and whey, weighing requires 42 THE BABCOCK TEST 43 too much time. Indeed, with these substances weighing 1s not necessary as sufficiently accurate samples are ob- Fig. 8- Two styles of Babcock testers, tained by measuring which is the method universally em- ployed. In making a Babcock test it is of the greatest importance to secure a uniform sample of the substance to be tested. 44 MARKET DAIRYING Apparatus. ‘This consists essentially of the following parts: A, Babcock tester; B, milk bottle; C, cream bottle; D, skim-milk bottle; E, pipette or milk measure; F, acid” measures ; G, cream scales; H, mixing cans; I, dividers. A. Babcock Tester. | This machine, shown in Fig. 8, consists cf a revolving wheel placed in a horizontal posi- tion and provided with swinging pockets for the bottles. This wheel is rotated by means of a worm wheel (lower machine) at the top of the tester. When the tester stops the pockets hang down allowing the bottles to stand up. As the wheel begins rotating the pockets move out causing the bottles to assume, a horizontal position. The wheel is enclosed in a cast iron frame provided with a cover. B. Milk Bottle. This has a neck graduated to ten large divisions, each of which reads one per cent. Each large division is subdivided into five smaller ones, making each subdivision read .2%. ‘The contents of. the neck from the zero mark to the 10% mark is equivalent to two cubic centimeters. Since the Babcock test does not give the percentage of fat by volume but by weight, the 10% scale on the neck of the bottle will, therefore, hold 1.8 grams of fat. In other words, if the scale were filled with water it would hold two grams; but fat being only .g as heavy, 2 cubic centimeters of it would weigh nine- tenths of two grams or 1.8 grams. This is exactly 10% of 18 grams, the weight of the sample used for testing. A milk bottle is shown in Fig. 9. C. Cream Bottles. These are graduated from 30% to 55%. A 30% bottle is shown in Fig. 10. Since cream usually tests more than 30%, the sample must be divided wher. the 30% bottles are used, THE BABCOCK TEST 45 Fig. 9.—Milk Fig.10.—Cream Fig. 11.—Skim-milk bottle. bottle. bottle. D. Skim-milk Bottle. This bottle, shown in Fig. 11, is provided with a double neck, a large one to admit the milk, and a smaller graduated neck for fat reading. The entire scale reads one-half per cent. Being divided into ten subdivisions eacn subdivision reads .05%. The same bottle is also used for testing buttermilk. 46 MARKET DAIRVING Fig. 13.— Fig. 14.— Acid meas- yi Acid meas- ure. ure. E. Pipette. This holds 17.6 c.c., as shown in Fig. 12. Since about .1 cc. of milk will adhere to the inside of the pipette it is ex- pected to deliver only 17.5 c.c., which is equiva- lent to 18 grams of normal milk. F. Acid Measures. In making a Babcock ie. test equal quantities, by volume, of acid and milk are used. The acid measure, shown in Fig. 13, holds 17.5 c.c. of acid, the amount needed for one test. The one shown in Fig. 14 is divided into six divisions, each of which holds 17.5 c.c. or one charge of acid, Where THE BABCOCK TEST 47 many tests are made a graduate of this kind saves time in filling, but should be made to hold twenty-five charges. H. A cream scales commonly used is illustrated in Fig. 15. Acid. The acid used in the test is commercial sul- Fig.15,—Cream scales. phuric acid having a specific gravity of 1.82 to 1.83. When the specific gravity of the acid falls below 1.82 the milk solids are not properly burned and particles of curd may appear in the fat.. On the other hand, an acid with a specific gravity above 1.83 has a tendency to blacken or char the fat. The sulphuric acid, besides burning the solids not fat, facilitates the separation of the fat by raising the specific gravity of the medium in which it floats. Sulphuric acid must be kept in glass bot- sig 1g-show- ties provided with glass stoppers. Exposure ing mannerot to the air materially weakens it. Dette. Making a Babcock Test.- The different steps are indicated as follows: 1. Thoroughly mix the sample. 2. Immediately after mixing insert the pipette into the milk and suck until the milk has gone above the mark on the pipette, then quickly place the fore finger over the 48 MARKET DAIRYING top and allow the milk to run down to the mark by slowly relieving the pressure of the finger. 3. Empty the milk into the bottle in the manner shown in Fig. 16. es 4. -Add the acid in the same manner in which the milk was emptied into the bottle. 5. Mix the acid with the milk by giving the bottle a slow rotary motion. 6. Allow mixture to stand a few minutes. 7. Shake or mix again and then place the bottle in the tester. —s1 8. Run tester four minutes at the a proper speed. = g. Add moderately hot water until —=—8 contents come to the neck of the a bottle. ot 10. Whirl one minute. = a 11. Add moderately hot water un- © z—1— til contents of the bottle reach about ea the 8% mark. a 12. Whirl one minute. = 13. Read test. ae =—s How to Read Milk Test. At the = | top of the fat column is usually quite a 4 = & pronounced meniscus as shown in Fig. 3—= 17, A less pronounced one is found = at the bottom of the column. The fat = should be read from the extremes of —o the fat column, 1 to 3, not from 2 to 4, on) : . 7 when its temperature is about 140° F. Fie. 17—3ak conumin Too high a temperature gives too high = showing meniscuses, THE BABCOCK TEST 49 a reading, because of the expanded condition of the fat, while too low a temperature gives an uncertain reading. Precautions in Making a Test. 1. Be sure you have a fair sample. 2. The temperature of the milk should be about 60 or 70 degrees. ‘ 3. Always mix twice after acid has been added. 4. Be sure your tester runs at the right speed. 5. Use nothing but clean, soft water in filling the bottles. \ 6. Be sure the tester does not jar. 7. ‘Be sure the acid is of the right strength. 8. Mix as soon as acid is added to milk. 9. Do not allow the bottles to become cold before reading the test. 10. Read the test twice to insure a correct reading. The water added to the test bottles after they have been whirled should be clean and pure. Water containing much lime seriously affects the test. Such water may be used, however, when first treated with a few drops of sulphuric acid. As stated before, skim-milk, buttermilk, and cream are tested in the same way as milk, with the exception that the cream sample is weighed, not measured. (See p. 51.) Testing Cream. Accurate tests of cream cannot be secured by measuring the sample into the bottle as is done in the case of milk. The reason for this is that the weight of cream varies with its richness. The richer the cream the less it weighs per unit volume. This is illus- trated in the following table by Farrington and Woll: 4 50 MARKET DAIRYING Weight of fresh separator cream delivered by a 17.6 c. c. pipette. Per cent. of fat Specific gravity Weight of creain in creain. (weighed). in grams. 10 1.023 17.9 15 1.012 17.7 20 : 1.008 17.3 25 1.002 17.2 30 .996 17.0 35 -980 16.4 40 .966 16.3 45 .950 16.2 50 947 15.8 With cream testing below 30% the full 18 grams may be added to one bottle and tested in the usual way. Where the cream tests above 30% better results are obtained by using only half the full sample of cream (9g grams) and adding to this 9 grams of water. To this mixture the full amount of acid is added. Obviously in this case the test must be multiplied by 2 to get the correct reading. General Pointers: Black fat is caused by 1. Too strong acid. 2. Too much acid. 3. Too high a temperature of the acid or the milk. 4. Not mixing soon enough. 5. Dropping the acid through the milk. Foam on top of fat is caused by hard water, and can be prevented by adding a few drops of sulphuric acid to the water. Unclean or cloudy fat is caused by 1. Insufficient mixing. 2. Too low speed of tester. 3. Too low temperature. 4. Too weak acid. Curd particles in fat are caused by 1. Too weak acid. THE BABCOCK TEST 51 2. Not enough acid. 3. Too low temperature. ; Cleaning Test Bottles. As soon as the test is read, the bottles are emptied by shaking them up and down su as to remove the white sediment. Next wash them in hot water containing some alkali, and finally rinse them with hot water. Occasionally the bottles should be rinsed with a special cleaning solution, which is made by dis- solving about one ouncé of potassium bichromate in one pint of sulphuric acid. A small brush should also oc- casionally be run up and down the neck of the bottle. Reading Cream Tests. Reading the extremes of the fat column, as is done in the case of milk tests, gives too high a reading. This error is due to the meniscus at the top of the fat column, the size of which varies with the width of the neck of the bottle. Farrington and Woll recommend reading from the lowest extremity of the fat column to the bottom of the meniscus. This is the method now commonly employed. Eckles and Wayman recom- mend removing the meniscus by adding a small quantity of amyl alcohol (colored red) to the top of the fat col- umn, This method gives very satisfactory results. CHAPTER VI. CREAMING. Cause. Creaming is due to the difference in the speci- fic gravity of the fat and the milk serum. The fat being light and insoluble rises, carrying with it some of the other constituents of the milk. The result is a layer of cream at the surface. Processes of Creaming. The processes by which milk is creamed may be divided into two general classes: (1) That in which milk is placed in shallow pans or long narrow cans and allowed-to set for about twenty-four hours, a process known as natural or gravity creaming; (2) that in which gravity is aided by subjecting the milk to centrifugal force, a process known as centrifugal creaming, The centrifugal force has the effect of increas- ing the force of gravity many thousands of times, thus causing an almost instantaneous creaming. This force is generated in the cream separator. Shallow-Pan Method. The: best results with this method are secured by straining the milk directly after milking into tin pans about twelve inches in diameter and two to four inches deep. It is then allowed to remain undisturbed at room temperature (60° to 65° F.) for twenty-four to thirty-six hours, after which the cream is removed either with a’nearly flat, perforated skimmer, or by allowing it to glide over the edge of the pan after it has been carefully loosened along the sides. The aver- age loss of fat in the skim milk by this method is 0.7%. 52 CRkLEAMING 53 Deep-Cold-Setting Method. The best results with this method are secured by using a can like the Cooley illustrated in Fig. 18. This can is provided with a cover which allows it to be submerged in water. It also has a spout at the bottom by which the skim milk is gently removed, thus preventing the partial mixing of cream and skim milk incident to skimming with a conical dipper. The milk is put into the cans di- rectly after milking and cooled to as low a temperature as possible. To secure the best results with this method the water should be iced. Where this is done the skim milk will show only about 0.2% fat. It it desirable to allow the milk to set twenty-four hours before skimming, though usually the creaming is quite complete at the end of twelve or fifteen hours. Dilution or Aquatic Separators. One of the most unsatisfactory methods of creaming is the addition of water to the milk. The creaming by this method is done in variously constructed tin cans, which the manufacturers usually sell under the name of dilution or aquatic sepa- rators. Those uninformed about the genuine centrifugal separators are often lead to believe that they are buying real separators at a low cost when they are investing five, ten or fifteen dollars in one of these tin cans, which are no more entitled to the term separator than are the com- mon shallow pans. The average loss of fat with this system of creaming is about 114%. Fig. 18.—Cooley Can. 54 MARKET DAIRYING Centrifugal Method (Hand Separator). Dairies hav- ing four or more cows should cream their milk by the cen- trifugal method, the hand separator. The saving of but- ter fat with this method soon pays for the cost of a sep- arator. Moreover it has the additional advantages over the gravity methods of creaming in providing fresh, sweet skim milk for feeding purposes, and yielding cream of any desired richness. , Efficiency of Creaming With a Separator. Under favorable conditions a separator should not leave more than .05% fat in the skim milk by the Babcock test There are a number of conditions that affect the efficiency of skimming and these must be duly considered in making a separator test. The following are some of these con- ditions : Speed of bowl. Steadiness of motion. Temperature of milk. Manner of heating milk. Amount of milk skimmed per hour. Acidity of milk. Viscosity of milk. Richness of cream. Stage of lactation. (Stripper’s milk.) emOnmMOOn> A. The greater the speed the more efficient the cream- ing, other conditions the same. It is important to see that the separator runs at full speed during the separating process. B. A separator should run as smoothly as a top. The slightest trembling will increase the loss of fat in the skim milk. Trembling of bowl may be caused by any of the following conditions: (1) loose bearings, (2) sepa- CREAMING 55 rator out of plumb, (3) dirty oil or dirty bearings, (4) un- stable foundation, or (5) unbalanced bowl. C. The best skimming is not possible with any sepa- rator when the temperature falls below 60° F. A tem- perature of 85° to 98° F. is the most satisfactory for ordinary skimming. Under some conditions the cleanest skimming is obtained at tempera- tures above 100° F. The reason milk separates better at the higher temperatures is that the viscosity is reduced. : D. Sudden heating tends to in- crease the loss of fat in skim-milk. The reason for this is that the fat heats more slowly than the milk serum, which diminishes the differ- ‘ence between their densities. When, for example, milk is suddenly heated from near the freezing temperature to 85° F. by applying live steam, the loss of fat in the skim-milk may be four times as great as it is under favorable conditions. E. Unduly crowding a separator increases the loss of fat in the skim milk. On the other hand, a marked underfeeding is apt to lead to the same result. F. The higher the acidity of milk the poorer the creaming. With sour milk the loss of fat in the skim milk becomes very great. G. Sometimes large numbers of undesirable (slimy) bacteria find entrance into milk and materially increase its viscosity. This results in very unsatisfactory creaning. Low temperatures also increase the viscosity of milk which accounts for the poor skimming at these tempera- tures, Fig. 19.—Cream Separa- tor. 56 MARKET DAIRYING H. Most of the standard makes of separators will do satisfactory work when delivering cream of a richness of 50%. A richer cream is liable to result in a richer skim- milk. The reason for this is that in rich cream the skim- milk is taken close to the cream line where the skim-milk is richest. I.. Owing to the very small size of the fat globules in stripper’s milk, such milk is more difficult to cream than that produced in the early period of lactation. Regulating Richness of Cream. The -richness of cream is regulated by means of a cream screw in the sepa- rator bowl. When a rich cream is desired the screw is turned toward the center of the bowl, and for a thin cream it is turned away from the center. Best Time to Separate Milk. The best results with a separator are obtained by running the milk through the machine immediately after milking. Saving of Butterfat With a Separator. That the owner of four good cows can afford to invest $50.00 in a small cream separator is shown by the following: Four goods cows will yield not less than 24,000 pounds of milk a year. By the common shallow pan method of creaming, the loss of butterfat will average 0.7 pound for every 100 pounds of milk. With the centrifugal sepa- rator the loss of fat will not average over 0.05 pound, hence there will be effected a saving of 0.65 pound of butterfat in each 100 pounds of milk by the use of the separator. At this rate, the total saving of butterfat an- nually on the 24,000 pounds of milk will be 156 pounds. Since each pound of butterfat will yield approximately I 1-6 pounds of butter, 183 pounds of butter will be saved by the process, which, at 25 cents per pound, CREAMING 57 amounts to $45.75. This saving in butterfat alone will almost pay for the separator in one year. Fastening a Separator. To secure steady motion, the separator must be fastened to a solid foundation. There is nothing better in this respect than a concrete floor, with which every dairy should be provided. - CONcR ETE Ce Fig. 20.—Method of Fastening Separator. There are two common methods of fastening a separator to a concrete floor: One is to fasten two 4x4-inch blocks to the concrete floor as illustrated in Fig. 20. The separa- tor is then fastened to these blocks in the same manner as to a wood floor. The other method of fastening consists in chiseling four conical holes into the concrete floor, at a distance corresponding with the four holes in the separator base. The cavities thus made are filled with babbitt metal,.into which holes a little smaller than the lag screws are drilled. The separator is then fastened by turning the lag screws into the babbitt (Fig. 21). 58 MARKET DAIRYING The babbitt may be dispensed with by fastening the bolts with cement as shown at the left in Fig. 21. Fig. 21.— Methods of Fastening Separator. CHAPTER VII. STANDARDIZING MILK AND CREAM. This is a process by which milk and cream are brought to a definite percentage of fat. Reducing Milk and Cream with Skim-milk. Cream producers are called upon to furnish cream of a definite richness, and different grades may be demanded by differ- ent buyers. The simplest way to meet such demands is to have the separator deliver cream somewhat richer than the richest grade called for and. to reduce this to the required richness by adding skim-milk. When a definite quantity of cream of a definite richness is to be made up in this way, the following formula will be found simple and direct: Formula: x C = D, in which A = test desired. B=test of original cream. C = number of pounds of standardized cream. D= number of pounds of original cream. Problem: How many pounds each of 45% cream and skim-milk (zero test) are required to make 60 pounds of 18% cream? Substituting in the above formula we have 28 ioe) the amount of original cream to be used. The amount of skim-milk always equals C — D. Sub- 59 60 MARKET DAIRVING stituting for C and D in the above problem we have 60— 24 = 36, the amount of skim-milk to be used. The same formula may be used to reduce milk to a lower percentage of fat by adding skim-milk. Enriching Cream and Milk by Extracting Skim- milk. If milk and cream are too low in fat, they may be made richer by extracting skim-milk according to the following formula: Formula: X = A — , in which X = number of pounds of skim-milk to be extracted. A= number of pounds of original milk. B = test of original milk. ‘ C=test desired. Problem: How many pounds of skim-milk must be extracted from 450 pounds of 4.0% milk to raise the test to 4.5%. Substituting in the above formula we have X = 450 — (==) = 50, the number of pounds of skim-milk to be extracted. The same formula. may be used to enrich cream by ex- tracting skim-milk. Mixing Two Milks or Two Creams, or Milk and Cream, of Different Richness. In the preceding two formulas the test of the skim-milk was considered zero. When milks or creams of different tests are mixed the calculation becomes more difficult. Pearson, however, has devised a method by which calculations of this kind are very much simplified. This method is as follows: Draw a rectangle with two diagonals, as shown below. At the left hand corners place the tests of the milks or creams to be mixed. In the center place the richness STANDARDIZING MILK AND CREAM 61 desired. At the right hand corners place the differences between the two numbers in line with these corners. The number at the upper right hand corner represents the number of pounds of milk or cream to use with the richness indicated in the upper left hand corner. Like- wise the number at the lower right hand corner repre- sents the number of pounds of milk or cream to use, with the richness indicated in the lower left hand corner. Example: How many pounds each of 30% cream and 3.5% milk required to make 25% cream? 3BO% 21.5 Les. 25% 35% 5 uss. 21.5, the difference between 3.5 and 25, is the number of pounds of 30% cream needed; and 5, the difference between 25 and 30, is the number of pounds of 3.5% milk needed. From the ratio of milk and cfeam thus found, any definite quantity is easily made up. If, for example, 300 pounds of 25% cream is desired, the number of pounds each of 30% cream and 3.5% milk is determined as fol- lows: 21.5 +5=26.5 21.5 265 X 300 = 243.4, the number of pounds of 30% cream. X 300 = 56.6, the number of pounds 5 26.5 Of 3.5% ‘milk, CHAPTER VIII. COLD STORAGE, Cold storage of some kind is indispensable to a well equipped dairy. Many, however, lack this essential, either because they do not appreciate its importance, or be- cause of the rather high price of commercial refrigerators. The value of low temperature in keeping milk sweet has frequently been shown by experimental data and is again shown here by the results of a large number of experiments recently conducted. by the author. The aver- age results secured in twenty-six experiments show that milk cooled to 45° F. one hour after milking contained 0.19 per cent acid; the same milk kept in the refrigerator at a temperature of 44° F. for fifteen hours showed 0.20 per cent acid, an increase of only o.o1 per cent. In another series of ten experiments milk cooled to 45° F. one hour after milking showed an average of 0.19 per cent acid; the same milk kept in the refrigerator at a temperature of 44° F. for twenty-four hours showed an average of 0.21 per cent acid, an increase of only 0.02 per cent. These results show that there is practically no develop- ment of acid in milk kept at a temperature of 44° F. (Bul. No. 198, N. C. Exp. Sta.) Ice Box for Small Dairymen. A simple, cheap and effective ice box that will answer the purpose of a refrig- erator for small dairymen has recently been constructed 62 by the author. x a SY FELT FELT ak A ak) =6Go 5 SY 2» Q by) EY SI BY EY Se a NAT WI St Ra WE Ra Rall BN Pall WA KS y BA F BY i EY BN ( A By RY | INH NW MHI IRE] © 10 GALLON CAN N i A Dh) PAIRS NS iss NS DAL IES NS \\ N 3° 7.86, BOARDS Si } A 1" STRIPS S| VAIN PAPER all Ry HY GALV IRON 7 p RI Ie y SINK B SUIS 2 Rall INS Wg SIS fs N ZEROES il \ N Fig. SO Ts ORAS SSS ERAN COLD STORAGE 63 A detailed description of this box, to- gether with a cross-sectional cut of the same, is herewith CET p SS re Ses SER ee = R= Sp LLIN eee oe LETT GALV IRON . ee Sz TFA 22,—Cross-Section of Ice Box. Sa ‘08 HINGE Ti s e1z = Zz o uo =z , mn r ti < / m PRINTING a AND / Bor Tune ! TABLE Fig. 65.—Floor Plan of Dairy House Suitable for Ten to Twenty Cows. and tack building paper on both sides. Weather board the outside and finish the inside as follows: Board up preferably with tongued and _ grooved lumber, and cover the boards with two thicknesses of THE DAIRY HOUSE 131 z > a tr m a Bower Meals a MNT ONISANIY | Drain HoUM NNEC wvals. BesrZmiyvaig “NIC Onisnty PRINTING! TaBLe SBAI3HS Bortiine Tasre Fig. 56.—Floor Plan of Dairy House Suitable for aoe to Fifty Cows. (Natural Refrigeration.) 18'x24 roofing paper. Next put on furring strips, one foot apart, and to these fasten wire lathing. If the lathing is pro- vided with one-inch steel ribs the furring strips are not lo av ww MARKET DAIRYING | Bortre FILER umnd0D Ssanians Banus G3iia MNIC DNICNIY MNIC HoOVM YNIG DONIGNIY 10 AP BoiterR Wooy ONILCAL Fig. 57.—Floor Plan of Dairy House Suitable for Twenty to Fifty Cows. (Mechanical Refrigeration.) 18’x30'. THE DAIRY HOUSE 133 needed. Next apply one and one-half inches of cement plaster consisting of one part cement, three parts clean, coarse sand, and one part slacked lime paste. Press the concrete partly through the wire lathing. Finish with one part cement and one part sand and trowel off as smoothly as possible. This construction provides one three-fourths inch and one four-inch dead air spaces. The appearance of a wall thus constructed is much im- proved by coating it with a cement filler which gives it a uniform grayish color. If this is followed by two coats of white enamel laboratory paint, the walls present a very sanitary appearance. The author has thoroughly tested this enamel paint and has found it very satisfactory. The walls of the milk room especially should be painted with the enamel to within two or three feet of the floor. Construct a four-inch concrete floor upon a well tamped foundation consisting of gravel, cobble stones and cinders. These materials afford good drainage and thus prevent the cold and dampness usually associated with concrete floors. In .preparing the concrete for the floor use one part cement, two parts clean, coarse sand and four parts gravel or crushed stone. Finish with one part cement and two parts sand. All parts of the floor should slope toward the drain in the center. Round out the corners and edges of the floor with concrete to make them more easily cleanable. To provide insulation for the concrete floor of the re- frigerator, asbestos or other insulating material is used as shown in Fig. 23. The asbestos must be protected from moisture by covering both sides with waterproof paper. The ceiling should be about twelve feet high and built of the best ceiling lumber. Keep the ceiling well painted. l 134 MARKET DAIRYING Enough windows must be provided to afford ample light and to admit sunshine to all parts of the building. Provide ventilation in the milk and wash rooms by running tight ventilating shafts from the ceiling through the top of the roof. Sewerage. Effective sewerage must be provided at the time the floor is laid. A bell trap (Fig. 58) should be placed in the center of each room and care- fully connected with the sewer. Conduct the sew- age far enough away to keep its odors a safe distance from the dairy house. See chapter XXVI. Method of Warming Dairy Houses. Dairy houses should’ be heated with steam, not with stoves. Either the exhaust steam from the engine or steam taken directly from the boiler may be used for this purpose. The heating pipes should be so arranged that either may be used when desired. A very satisfactory method of piping is to run one and one-half inch pipes from the boiler to within two feet of the floor, and close to the walls. ‘The pipes should pass around each room and end in a steam trap which dis- charges the condensed steam into a hot well located near the injector, so that the hot water may readily be drawn into the boiler. The heating pipes must all slope towards this well. A reducing valve should be placed near the boiler so that any amount of pressure may be carried in the heat- Fig. 58.—Bell Trap. THE DAIRY HOUSE 135 ing pipes. With a good valve of this kind a pressure as low as one pound may be carried when the boiler pressure varies from twenty to fifty pounds. Screening. Where proper sanitation is expected it is absolutely necessary to guard against flies, and this can easily be done by screening all doors and windows. Flies are a prolific source of milk contamination and must therefore be rigidly excluded from the dairy. CHAPTER XIX. MECHANICAL REFRIGERATION. In warm climates and in localities where ice is not obtainable or only so at a high cost, cold may be produced by artificial means known as mechanical refrigeration. This system of refrigeration is also finding its way into dairies that are able to procure ice at a moderate cost but which are seeking more satisfactory means of control- ling the temperature of their milk, cream and refrigerator. Most of the mechanical refrigerating machines in use at the present time belong to the compression type. What- ever is said here, therefore, will pertain strictly to this class of machines. Fig. 59 shows a desirable method of piping and also illustrates the circulation of the ammonia. The milk and cream are cooled with cold brine which is circulated by means of a pump. No ice is needed. When an especially low temperature of the brine is desired, as in making ice cream, valves A‘ (Fig. 59) are shut off and valves B opened, leaving all of the ammonia to circulate through the brine tank. . Principle of Refrigeration. The principle employed in mechanical refrigeration is the production of cold by the evaporation of liquids which have a low boiling point, like liquid ammonia, liquid carbonic acid, ether, etc. When a liquid evaporates or changes into the gaseous state it absorbs a definite amount of heat called heat of 136 MECHANICAL REFRIGERATION 137 vaporization or “latent” heat. Thus to change water from 212° F. to steam at.212° F. requires a considerable amount of heat which is apparently lost, hence the term latent (hidden) heat. >) DC o o 9 ° o e e ° o o Fe: 4 OE: Cows. g N\ ny REFRIGERATING ROOM COMPRESSOR. Fig. 59.—Showing Circulation of Ammonia in Mechanical Refrigeration. Ether changes into its gas at a much lower temperature than water which is illustrated by its instant evaporation when poured upon the hand. The heat of the hand in this case is sufficient to cause vaporization and the sensation of cold indicates that a certain amount of heat has been abstracted from the hand in the process. 138 MARKET DAIRYING Manifestly for refrigerating purposes a liquid must be used that can be evaporated at a very low temperature; for the cold in mechanical refrigeration is produced by the evaporation of the liquid in iron pipes, the heat for the purpose being absorbed from the room in which the pipes are laid. Anhydrous ammonia has thus far proven to be the best refrigerant for ordinary refrigeration. Anhydrous Ammonia (Refrigerant). This substance is a gas at ordinary temperatures but liquifies at 30° F. under one atmospheric pressure. In practical refrigera- tion the ammonia is liquified at rather high temperatures by subjecting it to pressure. The ammonia is alternately evaporated and liquified so that it may be used over and over again almost indefinitely. Circulation of Ammonia. The cycle of operations in mechanical refrigeration is as follows: The liquid am- monia starts on its course from a liquid receiver, and enters the refrigerating coils in which it evaporates, ab- . sorbing a large amount of heat in the process. By means of a compression pump, operated by an engine, the am- monia vapors are forced in the condenser coils where the ammonia, under pressure, is again liquified by running cold water over the coils. From the condenser coils it enters the liquid receiver, thence again on its journey through the refrigerating coils. The intensity of refrigeration is regulated by an ex- pansion valve, which is placed between the liquid receiver and the refrigerating coils. This valve may be adjusted so as to admit the desired quantity of liquid ammonia to the coils, Systems of Refrigeration. There are two ways in which the cooling may be accomplished by mechanical refrigeration: (1) by evaporating the liquid ammonia MECHANICAL REFRIGERATION 139 in a series of pipes placed in the room to be refrigerated ; and (2) by evaporating the liquid ammonia in a series of coils laid in a tank of brine and using the cold brine for cooling purposes. The former is known as the direct expansion system, the latter as the indirect expansion or brine system. Brine System. Brine should be exclusively used for cooling milk and cream and also largely for cooling the refrigerator. It is desirable, however, to have a few direct expansion coils in the refrigerator which may be used when extra cold is desired. The brine tank is located near the ceiling in the refrigerator where it will serve the same purpose as an overhead ice box. Refrig- erating pipes may also be laid in the milk room for the purpose of controlling its temperature during the warm summer months. The brine is kept*circulating by means of a brine pump. Strength of Brine. The brine is usually made from common salt (sodium chloride). The stronger the brine the lower the temperature at which it will freeze. Its strength should be determined by the lowest temperature to be carried in the brine tank. The table by Siebel on the next. page shows the freezing temperature as well as the specific heat of brine of different strengths. The fact that the specific heat grows less as the brine becomes stronger shows it to be wise not to have the solution stronger than necessary, because the less the specific heat the less heat a given amount of brine is able to take up. 140 MARKET DAIRYING Pounds of . | Per centage of salt by weight. sation oF pomtcen| apes solution. Nhe asasheslarn ue Sica aati laden Maal aseasa ea en 0.084 30.5 992 Do oinaoan a ae manner eee Tats aN 0.169 29.3 984 On guartus: 0s ta Sle eae oS he were Demag’ 0.256 27.8 -976 A ices 's seoies Dag a MARR dd oie Sula 0.344 26.6 968 Ouasertiee Wie Goes peleRe AG ee Cees ole 0.528 23.9 946 Since PIE SGA ROR NES vee aA 0.708 21.2 .919 LO echscetinceh BSE ahsetea mana esac, BE RWAT aR 0.897 18.7 892 TD iiwsesienge 2 Sutatca lg ¥ ahagaplasseidusielinve ses orw Feankta 1.092 16.0 874 DD ascatereibielydeon sieacwislnlaioa wae eemcenue 1.389 12.2 855 DO visrsiccsidrivde atalo ha waarmee ease ots 1.928 6.1 829 Deh sesh acetuls (a's @ 2 iSieha a aceeoaine daca et'elaleialahis 2.488 0.5 - 183 up itis nese heasiiotennansdenn a 2.610 -1.1| 70 Refrigerating Capacity. To speak of a machine of one ton refrigerating capacity, means that it will pro- duce, in the course of twenty-four hours, the amount of cold that would be given off by one ton of ice at 32° F. melting into water at the same temperature. Its actual ice making capacity is about 50% less. Size of Compressor. If the equivalent of five hun- dred pounds of ice is needed per day, then a half ton com- pressor will answer, provided it is run twenty-four hours a day. But since it will not likely be convenient to run the compressor more than six hours a day, a ma- chine four times this size will be’ necessary. The larger the compressor the shorter the time it needs to be run. A two-ton refrigerating machine will be large enough for a fifty-cow dairy. Power Required to Operate. The power required per ton of refrigeration is less the larger the machine. With a two-ton compressor, the power required is about two and one-half horsepower per ton of refrigerating capacity in twenty-four hours. MECHANICAL REFRIGERATION 141 Refrigerating Pipes. The refrigerating pipes vary from one to two inches in diameter. With moderately good insulation it is estimated that by the direct expansion system one running foot of two-inch piping will keep a room of forty cubic feet content at a temperature of 32° F. With brine nearly twice this amount of piping would be necessary. For cooling the brine in the brine tank, about 140 feet of 114-inch pipes are required per ton of refrigera- ting capacity. Expense of Operating. When a refrigerating plant has once been installed and charged with the necessary ammonia, the principal expense connected with it will be the power required to operate the compressor. This power is supplied by the engine that is used for the regu- lar dairy work. The ammonia, being used over and over again, will add but a trifle to the running expenses. Nor can the water used for cooling the ammonia vapors add much to the cost of operating. It is true, however, that the refrigerating plant will require some of the dairy- man’s time and attention, but this is probably no more than would be consumed in the handling of ice in the dairy. Charging and Operating an Ammonia Plant. ‘This subject is so ably discussed in The Engineer by H. H. Kelley that the author feels he can do no better than present the following extracts from that article. “When about to start an ice or refrigerating plant, the first thing necessary is to see that the system is charged with the proper amount of ammonia. Before the ammonia is put in, however, all air and moisture must be removed ; otherwise the efficiency of the system will be seriously interfered with. Special valves are usually provided for 142 MARKET DAIRYING discharging the air, which is removed from the system by starting the compressor and pumping the air out, the operation of gas cylinder being just the reverse of that when it is working ammonia gas. It is practically impos- sible to get all the air out of the entire system by this means, so that some other course must be taken to remove ‘any remaining air after the compressor has been started at regular work. This can be accomplished by admitting the ammonia a little at a time, permitting the air to escape through a purge valve, the air being thus expelled by dis- placement. The cylinder containing the anhydrous am- monia is connected to the charging valve by a suitable pipe, and the valve opened. The compressor is then kept running slowly with the suction and discharge valves wide open and the expansion valve closed. When one cylinder is emptied put another in its place, being careful to close the charging valve before attempting to remove the empty cylinder, opening it when the fresh cylinder is connected up. . “From sixty to seventy-five per cent of the full charge is sufficient to start with so that the air may have an opportunity of escaping with as little loss of ammonia as possible. An additional quantity of ammonia may then be put in each day until the full charge has been introduced. When the ammonia cylinders have been emptied and a charge of, say, seventy-five per cent of the full amount has been introduced, the charging valve is closed and the expansion valve opened. The glass gauge on the am- monia receiver will indicate the depth of ammonia. The appearance of frost on the pipe leading to the coils and the cooling of the brine in the tank will indicate that enough ammonia has been introduced to start with. It is sometimes difficult to completely empty an ammonia cylin- s MECHANICAL REFRIGERATION 143 der without first applying heat. The process of cooling being the same when the ammonia expands from the cylin- der into the system as when leaving the expansion valve, a low temperature is produced and the cylinder and con- nections become covered with frost. When this occurs the cylinder must be slightly warmed in order to be able to get all the ammonia out of it. The ammonia cylinders, when filléd, should never be subjected to rough handling and are preferably kept in a cool place free from any lia- bility to accident. The fact that ammonia is soluble in water should be well understood by persons charging a refrigerating system, or working about the plant. One part of water will absorb about 800 parts of ammonia gas and in case of accident to the ammonia piping or machine, water should be employed to absorb the escaping gas. Persons employed about a plant of this kind should be provided with some style of respirator, the simplest form of which is a wet cloth held over the mouth and nose. “After starting the compressor at the proper speed and adjusting the regulating valve note the temperature of the delivery pipe, and if there is a tendency to heat open it wider, and vice versa. This valve should be care- fully regulated until the temperature of the delivery pipe is practically the same as the water discharged from the ammonia condenser. With too light a charge of am- monia the delivery pipe will become heated even when the regulating valve is wide open. As a general thing when the plant is working properly the temperature of the refrigerator is about 15° lower than the brine being used, the temperature of the water discharged from the ammonia condenser will be about 15” lower than that of the condenser, the pointers on the gauges will vibrate the same distance at each stroke of the compressor and the 144 MARKET DAIRYING frost on the pipes entering and leaving the refrigerator will be about the same. By placing the ear close to the expansion valve the ammonia can be heard passing through it, the sound being uniform and continuous when everything is working properly. “When air is present the flow of ammonia will be more or less intermittent, which irregularity is generally notice- able through a change in the usual sound heard at the ex- pansion valve. The pressure in tne condenser will also be higher and the effect of the apparatus as a whole will be changed, and, of course, not so good. These changes will be quickly noticed by a person accustomed to the conditions obtaining when everything is in order and working properly. “The removal of air is accomplished in practically the same manner as when charging the system,- permitting it to escape through the purging valve a little at a time so as not to lose any more gas than is absolutely necessary. “The presence of oil or water in the system is generally detected by shocks occurring in the compressor cylinder. “In nearly all plants the presence of oil in the system of piping is unavoidable. The oil used for lubricating pur- poses, especially at the piston rod stuffing boxes, works into the cylinders and is carried with the hot gas into the ammonia piping, where it never fails to cause trouble. The method of removing the air from the system has already been referred to, but the removal of oil is accom- plished by means of an oil separator. This is placed in the main pipe between the compressor and the conderiser, and is of about the size of the ammonia receiver. Some- times another oil separator is placed in the return pipe close to the compressor which serves to eliminate any remaining oil in the warmer gas and to remove pieces of i MECHANICAL REFRIGERATION 145 scale and other foreign matter which, if permitted to enter the compressor cylinder, would tend to destroy it in a very short time. “The oil, which always gets into the system sooner or later and in greater or less quantity, depending upon the care exercised to avoid it, acts as an insulator and pre- vents the rapid transfer of heat from the ammonia to the pipe that ought to obtain, and also occupies considerable space that is required for the ammonia where the best re- sults are to be obtained.” 10 CHAPTER XX. KEEPING ACCOUNTS. Various methods are followed in keeping accounts with patrons, but nearly all of them involve the use of tickets, route book, and some form of ledger. The method here described is recommended because of its simplicity. Tickets. Most customers prefer to settle their milk and cream accounts daily. This they do by purchasing a quantity of tickets-from the milkman and handing them out every time milk or cream is purchased. The tickets should be used but once. Where they are repeatedly used they become dirty and a real source of danger. Passing from one household to another they are likely to become contaminated with disease germs and thus become the means of disseminating disease. The coupon ticket presented on the next page is one of the most satisfactory in use at the present time. The portion of the ticket above the perforations is retained by the milkman. If the ticket is paid for at the time of pur- chase, this must be indicated on the stub retained by the dairyman as well as on the customer’s ticket. Coupon tickets are also used for cream and buttermilk. Tickets for different products should have different colors. Tickets are not absolutely necessary ; indeed, many cus- tomers prefer to do without them. Where no tickets are 146 KEEPING ACCOUNTS 147 To TICKETS $1.00. MILK. Cr Loa ewoe - oh) MILK. wo... 4 a. ‘outs... L2C... B bee eat io & To SPRING VALLEY DAIRY, Dr. d. L. JONES, Prop., Middleton, N. Y. To TICKETS $1.00. es a0 e-POD me ee Oe pee oe ve, AOE ™ e SPRING TARSEY DAIRY. z i © ONE QT. MILK 3 MIDOLETON. N. Y. ee aye ee 28 ey SPRING vaLLey DAIRY. Re eG NS Fe em are 5 SPRING bel DAIRY. ® ONE QT. MILK 3 MIDDLETON. N. Y. Ee ee ee ‘LNId 3N9O 5 SPRING er DAIRY. 5 ; Ss * ,ONE Qy. MILK ® ONE QT. MILK 3 oo MODLETPNNY. | 4S MIDOLETDN NY. 5 = SPRING VALLEY DAIRY. z ®= ONE OV. MILK Fd aes SPRING vALLEY DAIRY. ONE QT. MILK SPRING VADLEY DAIRY. w ONE QT. MILK MIDDLETON, N.Y. wae ee ae wed oe | SPRING VAULEY DAIRY. {Nid aNO {LNId JNO }-untd 3NO 0 ttre tee ren Bee =e eg re ee eee : INT. , ON = ONE of. MILK “LNId JNO § “LNid JNO ae z 2 a ° w = w 5 MIDDLEYON. N.Y. = 3 MIDDLETON, N.Y. aes wpe -o ee ee we wee om we Be 8 ae es 5 SPRING VALLEY DAIRY. : 5 SPRING VALLEY DAIRY. 3 — m a m j ONE QT. MILK 215 ONE Qf. MILK = z z z z ° S 4, mIoDLEfoN. N.Y. ° MOLE: N.Y. Coupon Ticket. 148 MARKET DAIRYING used, an account is rendered at the end of the month similar to that rendered by the grocer. Route Book. It is evident that if customers were always supplied with tickets and regularly paid for each delivery of milk or cream, no further record would be necessary. But customers will run out of tickets oc- casionally as well as forget to regularly hand them out, hence it is necessary for drivers to carry with them a record or route book in which each transaction is recorded at the time it is made. A form suitable for this purpose is shown below. nor, C.4# ander, C. ® MILK CREAM BM BOTTLES. MILE. CREAM. BM i]s = 2 ie d/ii é ‘ ali Form of Route Book. The route book consists of loose leaves, upon which the names of customers are arranged alphabetically. The leaves are renewed each month, the old one being placed on file for future reference. The letters p.m. stand for buttermilk. ; Ledger. As a rule all accounts are settled monthly. The ledger form shown below serves satisfactorily as a permanent monthly record. On the debit side are recorded the sales and the total value of the tickets purchased. On the credit side are KEEPING ACCOUNTS 149 recorded all the receipts for the same period. The balance represents the difference between the debits and credits. Dr. dmcth Cr. TICKETS. TICKETS. : DATE a 4 DATE z i 1908, é a 1908 é al] fy sha} EAE ala): It 2 aan 18 79-0 |30|10| 10 |So}™ = —‘[G.oolzsi/o| & |% Bau. Jan 81 2:60\5 |0 | 2 |& Bau Fep.1 2.0/510/ 2 ye Form of Ledger. Monthly Statement. At the end of each month a statement should be rendered to customers showing their indebtedness. A form like that herewith shown answers the purpose satisfactorily. SPRINGDALE SANITARY DAIRY, J.C, BOONE, Proprietor : REIDSVILLE, N. Ltt. | 108 to SPRINGDALE SANITARY DAIRY, pe. J C. BOONE, Proprietor @e milk @ § @ 20 Fub.t~ 2% 4o VW r © Ss " a. ho. of Arwnrsiirnedg Monthly Statement. 150 MARKET DAIRVING Order Book for Supplies. For convenience as well as for~permanent record, all orders should be made in duplicate in a book specially made for the purpose. The leaves in the order book are alternately marked “original” and “duplicate,” the duplicate being made at the same time as the original by using carbon paper between the two. A suitable form of order blank is shown below. Original Springdale Sanitary Dairy. J. C. Boone, Prop. Order No. ........ Reidville, N. H. ......... 190... TOs Garson rem yada Mvedinnara meme einer J dew iiesin Deat Sir: Please deliver by............ the following: Invoice and ship to Springdale Sanitary Dairy, J. C. Boone, Prop., Reidville, N. 4. CHAPTER XXI. PASTEURIZATION OF MILK AND CREAM. The process known as pasteurization derives its name from the eminent French scientist Pasteur. It consists in heating and cooling milk and cream in a manner which will destroy the bulk of bacteria in them, but which will leave their chemical and physical properties unchanged as far as possible. Advantages of Pasteurization: The advantages to be derived from pasteurization vary with the conditions’ under which the milk is produced and the efficiency with which the work is conducted. If the milk comes from dairies where disease and uncleanliness prevail, pasteur- ization will prolong the keeping quality of the milk and also materially lessen the danger from disease germs. If, on the other hand, healthfulness and cleanliness re- ceive the exacting attention which prevails on certified dairy farms, nothing can be gained by subjecting milk to the pasteurizating process. Disadvantages of Pasteurization. The principal dis- advantages are as follows: (1) the cost of pasteurizing apparatus; (2) the cost of pasteurizing; (3) the tendency to promote uncleanliness on the part of the producer; (4) the tendency to reduce the cream line on the milk; (5) lessening of the whipping property of the cream; and (6) the tendency to impart a “cooked” flavor to the milk and cream. 2 Methods of Pasteurization. Two general methods 151 152 MARKET DAIRYING. are now in vogue: (1) the discontinuous method by which every particle of milk and cream is heated from ten to thirty minutes according as the temperature is high or low; (2) the continuous method by which milk and cream are permitted to pass in a constant stream through the pasteurizer and are subjected on an average less than one minute to the pasteurizing temperature. In general the most efficient pasteurization is obtained with the discontinuous method. — Pasteurizing Temperatures. Obviously where milk is heated only a minute or less, a higher temperature must be employed than where it is heated for a much longer period of time. With the continuous method the temperature varies from 160° to 180° F. With the discontinuous method the temperature varies from 140° to 155° F. Exposing milk or cream to a temperature of 145° F. for twenty minutes results in very satisfactory pasteurization. -The temperature and time of exposure should always be such as to insure the destruction of the tubercle bacillus, which is one of the most resistant of the disease bacteria most commonly found in milk. Quick Cooling. In pasteurizing the heating must be quickly followed by thorough cooling. This is an ex- tremely important part of the pasteurizing process. It is desirable that the temperature be reduced at once to 45° F. or below. Viscogin. Thorough pasteurization reduces the vis- cosity or whipping property of cream. To restore the original viscosity a solution gf sucrate of lime is added, which is known as viscogin. This solution is made by adding an excess of slaked lime to three parts of sugar dissolved in five parts of water. The mixture is al- PASTEURIZATION ~ 153 lowed to stand twenty-four hours, after which the clear liquid at the top is poured from the sediment and pre- served in a stoppered bottle. Add one part viscogin to about 150 parts of cream. Never add so much as to render the cream alkaline. While viscogin is entirely harmless, it is nevertheless an adulterant and cream treated with it must be so labeled. Inefficient Pasteurization. Milk that has been un- derheated is more dangerous than that which has not been heated at all. The reason for this is that inadequate heat in pasteurizing may destroy the lactic acid bacteria (which are easily killed) and by so doing actually better the conditions for the growth of the more resistant and obnoxious kinds. Lactic acid organisms are antagonistic to other classes of bacteria and are therefore a real safe- guard to milk. This makes it plain that unless milk is pasteurized at a temperature which will destroy the pathogenic and non-acid bacteria as well as the acid bac- teria, it is far better not to heat it at all. Pasteurization should be condemned where its only ob- ject is to keep milk sweet. Its real object should be to destroy all actively growing bacteria and especially all disease-producing organisms such as the tubercle bacillus which is among the most resistant. Pasteurizing inthe Home. I[f milk must be pas- teurized to render it safe, there is no better place to do this than in the home where it is to be consumed. The pasteurizing is very easily and satisfactorily accomplished by the use of a small double milk or rice boiler which can be procured for about one dollar from hardware deal- ers everywhere. It is essential to stir the milk while heating and to use a reliable thermometer. CHAPTER XXII. CERTIFIED MILK. Definition. Certified milk is milk produced under conditions imposed by medical milk commissions, which usually employ a veterinarian, a bacteriologist and a chemist to look after the production of the milk. It must Fig. 60.—Saunitary Dairy Barn. (Da. Div., U.S. Dept. of A.) be free from disease germs and preservatives, must have a known chemical composition, and must be so produced and handled as to insure a minimum number of bacteria. 154 CERTIFIED MILK 155 If the producer has complied with all the requirements he: is furnished a certificate by the commission, which permits him to use the “certified” label on his products. The term “certified milk” is registered in the United States patent office and its use is legally permitted only on milk approved by medical milk commissions. Uses. Certified milk is now largely used for infants and invalids. There is, however, also a rapidly increasing Fig. 61.—Truman Sanitary Milk Pail. (Storrs, Conn. Station.) use made of this milk by the better informed people who realize the unsanitary condition of average market milk. Certified milk is the means of saving the lives of thou- sands of infants and its increasing use offers splendid opportunities for dairymen who are in a position to meet the requirements laid aown by medical commissions. Production and Handling. The general conditions called for in the production of ‘‘certified” milk are essen- tially the same as those stated in the chapter on “‘sanitary milk production.” 156 MARKET DAIRYING The cows, milkers and premises are regularly inspected, and the milk is regularly subjected to chemical and bac- teriological tests. The number of bacteria permitted by different commissions varies from 10,000 to 30,000 per cubic centimeter of milk; and the fat content ranges from about 3.5 to 4.5 per cent. The milk bottles are sealed preferably with metallic caps bearing the date of bottling and the name of the commission, (see page 188). Delivery should be made within twenty-four hours after the milk is drawn and its temperature during this time should not exceed 45° F. In the dairy house arrangements must be such as to reduce contamination to a minimum. A receiving can placed in an ante-room is used by the milkers to empty their pails, and from this the milk is conducted into the milk room. A sterilizer with doors at both ends is pre- ferably placed between the milk room and the wash room, so as to enable the milkers to get their pails without’ enter- ing the milk room and, at the same time, to allow the sterilized bottles to be removed without entering the wash room. : ; Profits. Obviously it costs more to produce certified than average market milk, but the additional cost is less, as a rule, than the increased price realized. Certified dairies that have failed to make money have almost in- variably invested more money in buildings and equipment than was actually necessary. It has been shown that this class of milk may be successfully produced in quite ordi- nary buildings and with moderately cheap equipment. What is of greatest importance is extreme cleanliness, which is achieved mainly through intelligent care and management of every detail of the work from start to finish. CHAPTER XXIII. THE CARE OF MILK IN THE HOME, No matter how good the condition of the milk when delivered, if carelessly handled in the home it will keep sweet but a very short time and the dairyman will get the blame. It is of vital interest to dairymen, therefore, to instruct their customers in the proper care of the milk in the home. There is no doubt that a great deal of good milk is spoiled in the home of the consumer. This, as a rule, is the result of ignorance. Few consumers have a good knowledge of milk and, therefore, do not know how to care for it. If milk producers will bring the following suggestions to the attention of their customers, it may relieve them of much of the complaint they have hitherto been obliged to suffer: INSTRUCTIONS TO CONSUMERS. To keep milk and cream sweet and pure, they must be kept cold and clean. As soon as the milk is delivered, it should be put in a cool place—a clean refrigerator if possible. The vessels in which the milk and cream are kept must be sterile and covered. Vessels are not sterile unless they have been kept in boiling water for five minutes and then inverted upon a clean shelf without wiping. 157 158 MARKET DAIRYING On account of their great absorption properties milk and cream must be kept in covered vessels, especially when placed in the kitchen or cellar or possibly in the refrigera- tor with fruits and vegetables. Aside from absorbing odors when exposed in these places, they will also take up bacteria which will shorten their keeping quality. At 45° F. milk may be kept perfectly sweet for twenty- four hours, while at a temperature of 70° it may sour in less than six hours. This emphasizes the importance of cold in preserving milk and cream. Pour milk from one vessel to another as little as pos- sible to avoid contamination. The best plan is to keep it in the original bottles. Do not add new milk to old milk; neither add warm milk to cold. The tops of the bottles should always be washed before removing any milk. They are more or less contaminated with dust during transportation and also become soiled from the hands. Always clean the bottles before returning them. Finally it is well to remember that the lowest-priced milk is usually also the poorest and dirtiest. Such milk in the end will prove the most expensive. CHAPTER XXIV. THE BOILER AND ITS MANAGEMENT, A boiler is indispensible in a well equipped dairy. The steam which it provides is important, not only in securing hot water and in sterilizing, but also in furnishing power. A steam engine will be found useful in most dairies for pumping water, separating milk, churning and freezing cream, and by extending the shaft through one side of the building its usefulness may be extended to sawing wood, washing clothes, running the grindstone, etc. For the smaller dairies the upright form of boiler will be found the most satisfactory. But for dairies having upwards of fifty cows, the horizontal form of fire-tube boiler should be used. The latter style is laid in brick. The grates are supported upon brickwork and heat and smoke pass along the underside of the boiler toward the rear and return through the fire-tubes. To prevent radiation of heat the brick work must be built up to cover the entire boiler. The fire box must be constructed of the best fire brick. The various boiler accessories will be described in the following paragraphs: Glass Gauge. This is a glass tube attached to the side of the boiler to indicate the height of the water in it. It is so attached that its lowest point is about two inches above the highest part ofthe fire line of the boiler, its entire length being usually about fifteen inches. The 159 160 MARKET DAIRYING cock at the bottom is used to blow out the sediment that is liable to block the opening between it and the boiler. When this occurs the gauge becomes a false indicator. Frequent blowing out is therefore necessary. The cock next to the blow-out admits the water from the boiler. The cock above this admits the steam. When the glass breaks shut off the water first, then the steam. Always have a few extra glasses on hand so that the broken one can be immediately replaced. Owing to its tendency to clog, the gauge can not always be relied upon, hence the use of water cocks placed next to the glass gauge. Water Gauge Cocks: ‘There are three of these used. The water level should be kept as near as possible to the middle cock. It should never go below the lower cock, nor above the upper. These cocks should be opened many times during the day, and so long as steam issues from the upper and water from the lower cock, the water level is all right. Steam Gauge. This shows the number of pounds of steam pressure per square inch on the boiler by means of a pointer moving around a dial. Below the dial is a loop which contains water to prevent injury to the gauge from the hot steam. The steam gauge is liable to get out of order and will then fail to show the true pressure. Such a condition is indicated by the safety valve. Safety Valve. This is placed on top of the steam chamber and permits the escape of steam when the steam pressure reaches the danger limit. It is an indispensable boiler attachment as without it the boiler would be a dangerous thing. There are two kinds of safety valves, the “pop” and “ball and lever” types. The former is considered the more desirable because it is not so easily~ BOILER AND MANAGEMENT 161 tampered with. Both'can be set to blow off at different pressures. Water Feed Apparatus. There are two ways ot feeding water into a boiler, namely, with injectors and with pumps. ‘Injector. This important boiler accessory is attached to the side of the boiler. It utilizes the steam directly from the boiler for. forcing water into it against a pressure as great as that which sends it forth. The principle which makes this possible may be stated as follows: Steam issuing from a boiler under 70 pounds pressure has a velocity of 1,700 feet per second. When steam with this high velocity strikes the combining tube it produces suction which in turn induces a flow of water. As soon as the water enters the combining tube . it is given motion by the high velocity of the steam, which immediately condenses and moves with the water into the boiler at a comparatively low velocity. The energy, therefore, by which steam can force water into the boiler against its own pressure is the latent heat resulting from the condensation of the steam in the combining tube. From this it must be evident that the efficiency of the injector is dependent upon the completeness with which the steam condenses. This is clearly proven by every day practical experience. When, for instance, the feed water is too hot, the steam pressure too high, or the steam is wet, the injector fails to work properly because the steam does not sufficiently condense when it strikes the feed water. Starting the Injector: This is done by opening the supply water valve one or two turns, then the steam valve wide. ,If steam issues from the overflow admit a little more water ; if water overflows admit less. 1 162 MARKET DAIRYING Care of Injector. An injector will become coated with sediment or scale the same as the boiler and must, therefore, be frequently cleaned. This is best done by immersing it in a solution of one part muriatic acid and ten parts water. Allow to remain in this solution until the scale becomes soft enough to permit washing out. A clean injector rarely causes trouble but if trouble does occur it may be due to : (1) low steam pressure; (2) too hot water; (3) leaks in pipes and injector; (4) clogging of water pipe; (5) wet steam; (6) poor working condi- tion of check and overflow valves; (7) clogging of feed pipe where it enters the boiler. The injector is commonly used to feed water into the boiler because it is cheap and simple, and occupies little space, Pumps. There are two kinds; (1) those run with steam directly, and (2) those run by the engine. The latter is the more economical and handles hot water with less trouble. It has one disadvantage, however, and that is it does not work unless the engine is running. With good pumps, especially those run by the engine, good work may be expected when the feed water has been heat- ed to 200° F. with the exhaust steam from the engine. With the injector such high temperatures are not per- missible, hence the greater economy of the pump. The great saving of fuel by feeding water hot into the boiler is illustrated by experiments made by Jacobus which show that with a direct acting pump 12.1% fuel is saved by heating the feed water from 60° to 200° before pump- ing it into the boiler. With injectors the feed water used usually has a temperature of about 60° F. Steam. Water is practically a non-conductor of heat. This means that it cannot conduct its heat to its neighbor- BOILER AND MANAGEMENT 163 ing particles. When, therefore, heat is applied to the bot- tom of a vessel containing water, the particles at the bottom do not communicate their heat to the particles next above them, but expand and rise, cool ones taking their places.. This gives rise to convection currents which tend to equalize the temperature of the water in the vessel. When the water has reached a uniform temperature of 212° F. the particles begin:to fly off at the surface in the form of vapor, and this we call steam. To generate steam in a boiler, then, it is necessary to impart to the water in it a considerable amount of heat, which is produced by burning fuel in the fire box. FIRING OF BOILER. The immense amount of heat stored in wood and coal is rendered effective in the boiler by burning (combus- tion). To understand how to fire a boiler intelligently one must first learn what the process of burning consists of. Process of Burning. Anything will burn when the temperature has been raised high enough to cause the oxygen of the air to unite with it. Thus, in “striking” a match the temperature is raised high enough by the friction produced to cause the match to burn. The burn- ing match will produce heat enough to ignite the kind- ling, which in turn, produces the necessary heat to ignite the wood or coal in the fire box of the boiler. Burning may, therefore, be defined as the union of the oxygen of the air with the fuel. In burning a pound of coal or wood a definite amount of air must be admitted to furnish the necessary oxygen for complete combustion. When oxygen is lacking part of the fuel passes out of the chimney un- 164 MARKET DAIRYVING burned in the form of gases. If, on the other hand, too much air is admitted the excess simply passes through the chimney, absorbing heat as it passes through the boiler. The problem of firing becomes, therefore, a diffi- cult one. Burning Coal and Wood. When hard coal is burned the fire should be thin. A thickness of three to four inches on the grates gives very satisfactory results. For best results with soft coal a thickness of six to seven inches is recommended. Whenever fresh coal is added it should be placed near the front and the hot coals pushed back. In case wood is burned the fire box should be kept well filled, care being necessary to keep every part of the grates well covered. GENERAL POINTERS ON FIRING. 1. ‘Boilers newly set should not be fired within two or three weeks after setting and then the firing should be very gradual for several days to allow the masonry to harden without cracking. 2. Never fire a boiler before determining the water level by trying the water gauge cocks. You can not entirely rely upon glass gauges, floats, and water alarms. 3. When starting the fire, open the upper water gauge cock and do not close it until steam begins to issue from it. This permits the escape of confined air. 4. Kindle the fire on a thin layer of coal to protect the grate bars. 5. Always examine the safety valve before starting a fire. ; 6. When starting the fire all drafts should be open. BOILER AND MANAGEMENT 165 7. The firing should be gradual until all parts of the boiler have been heated. 8. Never allow any part of the grate bars to become uncovered during firing. g. Frequently clean the ash pit to prevent overheating of grates from the hot cinders underneath. 10. The coals upon the grates should not be larger than a man’s fist. 11. Remember that firing up a boiler rapidly is apt to cause leaks. 12. "Remember that too little water in the boiler causes leaks and explosions. 13. Remember that soot and ashes on heating surfaces always waste fuel. 14. When fire is drawn, close dampers and doors of furnace and ash pit. 15. .Never open or close valves when the water is too low in the boiler, but immediately bank the fire with ashes or earth. Opening the safety valve at such a time will throw the water from the heated surfaces, resulting in overheating and possibly in explosions. 16. Use the poker as little as possible in firing. 17. Keep the grate bars free from “clinkers.” 18. When the steam pressure goes too high, start the pump, open the doors of the furnace and close the ash pit. . 19. A steady and even fire saves fuel. GENERAL CARE OF BOILER. 1. Always close the steam and water valves of the glass gauge when you leave the building for half an hour or more. 166 MARKET DAIRYING 2. Water gauges should frequenty be blown out and cleaned. 3. Keep the exterior of the boiler dry. Moisture will corrode and weaken it. 4. The boiler should be blown off under low pressure every two or three days. 5. A boiler that is not used for some time should be emptied and dried. If this cannot readily be done, fill it full of water to which a little soda has been added. 6. Frequently examine the safety valve to see that it is in good working order. it 7. Do not empty boiler while brick work is very hot. 8. Never pump cold water into a hot boiler. Leaks and explosions may be the result. 9. Leaky gauges, cocks, valves, and flues should be repaired at once. 10. Do not fail to examine the pressure gauge fre- quently. , 11. It is good policy to have two means of feeding a boiler. The pump or injector may get out of order and cause delay and danger. 12. Feed pumps and injectors need frequent cleaning to keep them in good working order. 13. Look out for air leaks. If air is admitted any- where except through the grates serious waste may re- sult. Such leaks are to be looked for in broken doors and poor brick work. 14. Flues should be cleaned often, especially if soft coal is burned. This will prevent overheating of metal and at the same time save fuel. 15. Do not allow filth to accumulate around the boiler or boiler room. 16. Keep all the bright work about the boiler “shiny.” BOILER AND MANAGEMENT 167 17. Do not fail to empty the boiler every week or two and refill with fresh water. 18. Have your steam gauge tested at least twice a year. BOILER INCRUSTATION. In all boilers after a period of use, there is deposited upon the parts below the water level a scale or sediment known as boiler incrustation, Cause of Scale. The formation of scale is due to the impurities contained in the feed water. When impure water is fed into the boiler the impurity first manifests itself in the form of scum on top of the boiling water. The heavier particles of the scum slowly unite and sink to the bottom where they first appear as mud. By con- tinued exposure to high temperature, this mud gradually forms into a hard impervious scale which usually con- sists largely of lime. Objection to Scale: 1. The excessive formation of boiler scale is the immediate cause of most boiler explo- sions. The scale acts as a non-conductor of heat, so that in cases where the capacity of the boiler is severely taxed, the metal becomes overheated, thus materially weakening it. The scale is, therefore, not only dangerous, but by overheating the metal, also materially shortens the life of the boiler. 2. Another most serious objection to scale is its wastefulness of fuel. This becomes evident when we note that the heat before reaching the water must first be conducted through a non-conducting layer of incrusta- tion. Prevention of Scale. Since nearly all water used for boilers is more or less impure, it is evident that to prevent scale, boilers must receive frequent cleaning. How often 168 MARKET DAIRYING this needs to be done is, of course, dependent upon the amount and character of the impurity in the water. Boilers are kept clean in three different ways, (1) by blowing off at low pressure, (2) by cleaning through manhole, and (3) by using boiler compounds. (1). By blowing the boiler off at low pressure most of the mud will be blown out. But care must be taken that the pressure is not above ten pounds and that there is no more fire in the fire box, otherwise the mud, instead of flowing out with the water, will bake on and form scale. (2). A good way of removing mud is to allow the boiler to cool off and then run a rubber hose through the manhole. By working the hose and forcing water through it the sediment can be removed. (3) Boiler compounds are used to-keep boilers free from scale. The kind of compound to be used is deter- mined by the character of the impurities of the water. Most dairies use well water for the boiler and the chief impurity in this is lime. The best compound for water of this kind is soda. Well water contains the lime in widely different proportions. In order, therefore, to as- certain the proportion of soda to feed water the following method is recommended by Hawkins: “t. Add one sixteenth part of an ounce of soda to a gallon of the feed water and boil it. 2. When the sedi- ment thrown down by the boiling has settled to the bottom of the kettle, pour the clear water off and add one-half drachm of soda to this. Now, if the water remains clear, the soda which was put in has removed the lime. But if it becomes muddy, the second addition of soda is neces- sary.” In this way the amount of soda to be added to the feed water can be calculated with sufficient accuracy. BOILER AND MANAGEMENT 169 Tan bark is very efficient in removing boiler scale but may injure the iron. Kerosene answers the same purpose but renders the steam unfit for use in the dairy. When the water is salt or acid, a piece of metallic zinc occasionally placed in the boiler will prevent corrosion. Water of this kind can usually be told by its corrosive effect on copper and brass. Acid water can also be de- tected with blue litmus paper, which it turns red. WET AND DRY STEAM. Wet Steam. This is steam holding in suspension ex- tremely small particles of water which are thrown off from the water surface while steam is generating. The following are the causes of wet steam: 1. Impure water in the boiler. 2. Too much water in the boiler. 3. Too little evaporating surface for the amount of steam used. ‘This is one of the chief objections to upright and too small boilers. 4. Violent agitation of the water in the boiler caused by too rapid a generation of steam. Wet steam causes “priming” and is wasteful of heat. Dry Steam. This is saturated steam holding no water mechanically in suspension. High steam pressure and a large steam space above the water level are conducive to dry steam. CHAPTER XXV. WATER AND ICE SUPPLY. WATER SUPPLY Importance of Pure Water. A great deal of disease in farm homes is directly traceable to infected water. Typhoid fever especially is so frequently caused by pol- luted well water that physicians at once look to this as the probable cause wherever this disease is found to ex- ist. Where wells infected with disease germs happen to ex- ist on dairy farms that supply milk to neighboring cities, disease is not limited to the dairyman’s own family, but may be spread along the entire milk route. Many typhoid fever epidemics have been positively traced to milk which has become infected through water containing the disease germs. Nowhere is pure water so important, therefore, as upon dairy farms. The disease germs usually find their way into the milk through milk vessels which have been washed with in- fected water. The use of such water for washing cows’ udders previous to milking may also be the means of in- fecting the milk supply. Location of Well. The most satisfactory location for the well is at the dairy house where the coldest water is required and where it will be most convenient. Here the water for both the dairy, the home, and the stock can be pumped with the dairy engine. Further, the well, like 170 WATER AND ICE SUPPLY 171 the dairy house, should stand on slightly elevated ground so as to insure drainage away from it. Construction of Well. In a properly constructed well, no water should enter it except near the bottom. This compels the water to pass through a thickness of earth sufficient to purify it where the wells are of a reasonable depth. Where there is no rock or hard clay and where the Ordina ry Well i Mrtesian Wel LMM « Ei Ft el ele Fig. 62.—Soil Strata. (From Harrington’s ‘Practical Hygiene.’’) water can be had at a reasonable depth, the driven well, commonly known as the Abyssinian tube well, is the cheapest and one of the safest. This well is made by driving into the ground a water-tight iron tube, the lower end of which is pointed and perforated. In case rocks and hard clay must be penetrated, or great depth must be reached to secure water, the bored or drilled well, piped from top to bottom with water-tight iron pipes, will be found most satisfactory. 172 MARKET DAIRYING Water from the upper pervious stratum should be avoided wherever possible, even with wells of the kind just described. Especially is this necessary where the wells are shallow. The purest water is obtained by sink- ing the well through an impervious stratum, like that shown in Fig. 62. The most dangerous well is the common dug well with pervious walls and so located as to permit seepage into it from outhouses, barnyards and cesspools. Wells of this type are altogether too common on dairy farms. Fig. 63.—Sources of Well Water Contamination. (From Bul. 143 Kan. Exp. Sta.) All wells, whatever their construction, must be provided with water-tight metallic or concrete covers to prevent the entrance of impurities into the shaft. ICE SUPPLY. Necessity of Ice. Where there is no equipment for IVATER AND ICE SUPPLY 173 mechanical refrigeration, ice is indispensible in furnish- ing the best quality of milk and cream. A low enough temperature cannot be secured with water alone, neither can the cooling be accomplished as quickly as is desirable for best results. Furthermore, a satisfactory cold storage cannot be had without the use of ice. Cooling Power of Ice. A great deal of cooling can be done with a comparatively small amount of ice. This is due to the latent or “hidden” cold in ice. Thus to convert one pound of ice at 32° F. into water at the same temperature requires 142 units of heat, or, in other words, enough cold is given out to reduce the temperature of 142 pounds of water one degree Fahr. Construction of Ice House. To keep ice satisfactorily three things are necessary, (1) good drainage at the bot- tom, (2) good insulation, and (3) abundant ventilation at the top. ~ Good drainage and insulation at the bottom can be se- sured by laying an eight-inch foundation of stones and gravel and on top of this six inches of cinders, the whole being underlaid with drain tile. One foot of sawdust should be packed upon the cinders and the ice laid directly upon the sawdust. Satisfactory walls are secured by using matched boards on the outside of the studs and common rough boards on the inside, leaving the space between the studs empty. The ice should be separated from the walls by one foot of sawdust. Where no solid foundation walls are provided, earth must be banked around the ice house to prevent the en- trance of air along the base. The space between the sawdust covering on top of the ice and the roof should be left clear. Openings in the 174 MARKET DAIRYING gable ends as well as one or two ventilating shafts pro- jecting through the roof should be provided to insure a free circulation of air under the roof. This will not only remove the hot air which naturally gathers beneath the roof, but will aid in drying the sawdust. The ice must be packed solidly, using no sawdust except at the sides and bottom of the ice house and on top of the ice when the filling is completed. At least one foot of sawdust must be packed on top of the ice. Size of Ice House. The size of the ice house will depend, of course, upon the amount of ice to be used. For a herd of 25 cows, in the North, an ice house 10 feet square by 14 feet high will usually answer. These dimensions provide storage’ for 22 tons of ice, allowing one-foot space all around the ice for sawdust. In the South about 50% more ice is required than in the North. In calculating the amount of storage space needed for ice, it is necessary to know that one cubic foot of ice at 32° F. weighs 57.5 pounds. As a matter of convenience in filling and emptying the ice house, doors should be provided in sections from the ~ sill to the gable at one end of the building. General Uses of Ice. Aside from the use of ice in cooling milk and cream, it can be employed to good ad- vantage in several other ways. Its value in the house- hold, in preserving meats, vegetables, and fruits cannot be overestimated. And what is so refreshing as cold drinks and frozen desserts during the summer months! Ice is also frequently necessary in case of sickness. Cost of Making Ice. Where ice can be obtained with- in a reasonable distance, the cost of cutting, hauling, and packing should not exceed $1.50 per ton. Source of Ice. Always select the cleanest ice available. WATER AND ICE SUPPLY 175 Where the source of ice is at too great a distance from the dairy, an artificial pond should be made upon ground with a reasonably impervious subsoil and with a natural concave formation. If such a piece of ground is flooded with water during the coldest weather, an ample supply of ice will be available in a very short time. CHAPTER XXVI. SEWAGE DISPOSAL FROM DAIRY AND DWELLING, To secure a high degree of sanitation in and about the dairy house it is necessary to see that proper disposal is made of the sewage from both the dairy and the dwelling. Where the latter is situated close to the dairy house its surroundings may do fully as much harm as those of the dairy itself. With open privies and the careless dumping of kitchen slops near the dwelling, we have a double means of en- dangering the dairy. If the ground near the dwelling and privy slopes in the direction of the water supply, the latter is likely to become contaminated through seepage in the manner indicated in Fig. 63. In addition to this there is the danger of flies carrying various kinds of bacteria from these places to the dairy house. Flies not only carry the obnoxious, putrefactive species, but too often also the deadly pathogenic kinds, such as cause typhoid fever, to say nothing of the offensive excrementitious matter conveyed in this manner. Obviously the accumulation of sewage about the dairy house is attended by practically the same danger as that arising from the unsanitary surroundings of the dwelling. Moreover there is certain to be trouble also from bad odors. SEPTIC TANK. The best means of taking care of the sewage from 176 SEWAGE DISPOSAL 177 both the dairy and the dwelling is to run it into a septic tank (see Fig. 64, designed by the author) and from this into a net-work of tile laid underground where it will irrigate and fertilize the soil. Object of Septic Tank. The main purpose of the tank, as its name indicates, is to thoroughly decompose all organic matter entering it. This is accomplished by numerous species of bacteria, and the tank may be properly designated as a germ incubator. Where the VENT. NO LINE AiR INLET WASTEWATER FROM Zz r m 4 ey ( { I 3 >- 12 t 16 r ln =) > Fig. 64.—Septic Tank. sewage is emptied into underground tile, the tank also serves as a storage, discharging its contents intermittently. This is necessary to force the liquid to all points of the system and to allow time for each discharge to soak away before the appearance of the next. Construction of Tank. The general plan of construc- tion is illustrated in Figs. 64 and 65. The tank is located in the ground with the top within a foot or two of the surface. For durability it is preferably constructed of brick, stone or concrete. The tank is so constructed as to 2 178 MARKET DAIRYING retain all sediment and floating material, since the dis- charges permit the withdrawal of the liquid from near the middle of the tank only. This is one of the main features of the tank. All inorganic matter entering the tank will gradually settle and, of course, remain in it. Some of the organic matter tends to settle during the first 24 hours, a eee eran ee after which it comes to the orcpate ape surface to be gradually wasted away by the action of bacteria. This wasting away is naturally very slow, and since the slowly gathering organic matter 7 e nearly all remains in the ne aha first section of the tank, this must be large enough to provide for a consider- Fig. 65.—Cross Section of Septic Tank. able accumulation of it. The tank should be built air tight, except in two places. At the right is an air inlet, consisting of a goose-neck pipe, which renders the vent at the top more effective. This vent consists of a long shaft extending beyond the top of the dairy, thus carrying off the foul gases caused by the decomposition of the material within, One-inch gas pipe, properly fastened, will serve as a satisfactory vent. In order to afford communication of sections A and C with the vent, the two partitions should not be built quite as high as the tank. There should be at least one inch space between the top of the partitions and the cover. A 1%-inch gas pipe should be laid over the tank through which the water from the cooler and vats may be discharged directly into the drain. This water SEWAGE DISPOSAL 179 requires no purification and, if conducted through the tank, would necessitate one of too large dimensions. ‘Moreover, the large amount of cold water needed for cooling milk and cream would cool the contents of the tank too much for a rapid decomposition of the material within. Size of Tank. This must necessarily depend upon the amount of sewage run into it. In general it should have capacity sufficient to hold all of one day’s waste in the smallest section (C). It will be noticed from the cut that section A is considerably larger than either of the other two. The reason for this is that nearly all of the inorganic matter remains in the bottom of this part of the tank, while the organic matter, as already stated, gradu- ally accumulates at the surface in this section, in spite of constant decomposition. Where the tank receives the sewage from both the dairy and the dwelling, a tank 12 feet square by 414 feet deep will be large enough, provided the water used for cooling is not run into it. It is well to remember, however, that the larger the tank used the better the results that may be expected from it. Flow of Sewage Through Tank. Four-inch tile, carefully laid, may be used to conduct the sewage from the dairy to the tank. A trap is placed near the dairy to shut off the odors coming from the drain. At the point at which the sewage enters the tank it is desirable to attach an elbow with an arm sufficiently long to keep the lower end always in the sewage. This prevents un- due mixing of the incoming sewage with that already in the tank, a matter of importance in the successful operation of the tank. When the sewage in section A has reached the dotted line, it begins to discharge into section B through three- 180 MARKET DAIRYING inch gas pipe as shown in Fig. 64. The liquid is with- drawn from a point near the middle of the tank as in- dicated by the discharge pipes. The eight-inch space above the discharge permits the accumulation of organic matter. The discharge from 'B into C, is the same as that from A into B; but the discharge pipes are of neces- sity lower by an amount indicated by the dotted lines. Compartment C discharges intermittently by means of an automatic syphon. The sewage becomes gradually purified in its passage through the tank, and as it flows from the last section it is nearly as clear as water, but has a slightly sour odor, which it seems to retain and which is in no way objection- able. The purified sewage has been kept for weeks with no sign of the development of putrefactive odors. The discharges should be arranged as shown in Fig. 65. This arrangement will cause the least mixing of old and new sewage. There is no discharge from A into 'B until the second day’s sewage flows into A. Similarly there is no discharge from B into C until the second discharge into B, etc. The sewage, therefore, requires from three to four days in its passage through the tank. Cost of Septic Tank. A double partition tank, 12 feet square and 4% feet deep, constructed of concrete consisting of one part cement, two parts sand and four parts gravel, will cost approximately $50.00 when the walls are five inches thick. SEWAGE DISPOSAL FROM DWELLING. The open privy and the cesspool of kitchen slops are objectionable not only in so far as they affect the dairy house, but also in that they constitute a source of danger to the members of the family in ways entirely discon- nected with the milk supply. With the dairy house SEWAGE DISPOSAL 181 already equipped with power to pump and elevate water, there is apparently no reason why the dwelling should -not be equipped with a water closet. And with a water closet in the house there would be practically no expense connected with the disposal of the kitchen waste, since this would be discharged directly into the soil pipe con- . hected with the closet. What a convenience such an equipment would afford to the housewife and members of the family! If the dwelling and dairy house are reasonably close together, one septic tank will answer for both. In such a case the tank is located between the two buildings. Where a great distance separates the buildings, a tank is provided for each and the outlets are brought together as near the tank as possible to save extra expense of tile. SUBSURFACE IRRIGATION. While the septic tank sufficiently decomposes the organic matter to leave the sewage from the tank without offensive odors, it is best to run the discharge into a system of underground tile where it will serve as a fer- tilizer and as an irrigating agent. The tile should be laid below the frost line. In loose soils one foot of tile per gallon of sewage will answer. Clayey soils require two to three times this amount. Three-inch agricultural drain tile are best adapted for drainage work of this kind, the tile being laid with open joints and with a slope of three or four inches per hundred feet. It is important that this subsurface irrigating system be located where there is no seepage into the water supply. In places where there is no danger from frost it is best to lay the tile only about one and one-half feet below the surface. - APPENDIX. Relationship of Fat and Solids-not-Fat. In normal milk a fairly definite relationship exists between the fat and the solids-not-fat. That is, milk rich in fat is like- wise rich in solids-not-fat. This is an important point for the consumer to bear in mind, because when he buys milk rich in fat he gets milk which is also rich in the more important food constituents, namely, the proteids. Composition of Cream. Cream contains all the con- stituents found in milk, though not in the same proportion. The fat may vary from 8% to 68%. As the cream grows richer in fat it becomes poorer in solids not fat. This is illustrated in the following figures by Richmond: Solids Total solids. not fat. Fat. Per cent. Per cent. | Per cent. 32.50 6.83 25.67 37.59 6.14 81.45 50.92 5.02 45.90 55.05 4.65 ‘60.40 57.99 4.17 53.82 68.18 3.30 64.88 The same authority also reports the following detailed analysis of a thick cream: 182 APPENDIX Per cent. Water ci2ssueniavescenqteadatescaneees 30.37 FAG 5.2 seasstiwsis waa eytdanu alee 3 a Ba ahaeleraee 56.09 SUBAB: 2h) aaccu xin oe eeaans Shes ateburaese 2.29 Protei ds: is wananeyethhd SeSSes Cees A aroee 1.57 INSTA tatte. cece nantes cea toonntinae ene votes 38 183 Composition of Buttermilk. According to Vieth, buttermilk from ripened cream has the following compo- sition: Per cent. Water sviwer ae alanis cad Gamiebers 90.39 Bat) 2% csdnntnanns raed tein wa end tas .50 Malle SUG as iucadsccarieducisisaied ng acetate ak 4.06 Lactie ACid ec scw ovine wdaiawigleiea whaedneacs .80 Proteitds since sds aeeeecnvends Sowa ere 3.60 ASH ss22e.ceueescaes Paihgauehe Cm ninedieceeess 75 Dairy buttermilk should not average above .2% fat. Composition of Skim-milk. Richmond has the following average composition of separator skim- found milk: Per cent. WB GOB a aac ars ee “ecaepd aaa tk eee a carapenaeabienes 90.50 Bat ce s.0s eins Dear eh reencidraraeeravancnedirs thst ceete 10 Milk Stigar eennceccuiadsieiae aewacatns 4.95 Casein, susness<.adauacaa eats ai eeeane ss 3.15 ALBUMEN 2 hi § ood aihajoda ee nauiaclasen 42 ASH, dvienugisaianenaetah cum vndemein Ye eated 78 CCMPARISON OF CENTIGRADE AND FAHRENHEIT THER- MOMETER SCALES. Thermometer. om Cc. Boiling point (Water) ...... cece cece cece nee eee en cee ees 212 100 Freezing point (Water). .... ss sseeseeeee rev eeeee seen ce 32 0 Difference between boiling and freezing point....... 180 100 184 MARKET DAIRYVING From the above it will be seen that one degree Centi- grade is equivalent to 9-5 degrees Fahrenheit. Hence the following rules: 1. To change C. into F. reading, multiply by 9-5 and add 32. Example: 50°C = (50 x 2) + 32 = 122°F, 2. To change F. into C. reading, subtract 32 and multiply by 5-9. Example: 182°F = (182 —. 32) x § =834°C. METRIC SYSTEM OF WEIGHTS AND MEASURES. This system was devised by the French people and has very extensive application wherever -accuracy in weights and measures is desired. Some of its equivalents in ordinary weights. and measures are given in the follow- ing table: Ordinary weights and measures. Equivalents in metric system. 1 Ounce (ay) paca ceiesgean rs inednedsexeco meats 28.35 grams. 0.9464 liter. 3.7854 liters. .| 29.57 eubie centimeters (c.c.) ....| 0.4536 kilogram. -| 64.8 milligrams. 2.54 centimeters. 0.3048 meter. APPENDIX 185 LINING UP SHAFTING. Fasten a heavily chalked string along the ceiling paral- lel to the direction the shafting is to take. Snap the string, and a. white mark will indicate the position of the shafting in a plane parallel to the floor. This plane is indicated by the line ab in Fig. 66. Next determine the position of the shafting in a plane at right angles to the D Fig. 66.—Intersecting Planes. Fig. Vee coenie aia floor, indicated by the line cd. This is done as follows: Loosely fasten the hangers along the white chalk line and properly fasten the shafting. Now hang on the shaft- ing, at intervals of three feet, pieces of board like that shown in Fig. 67. The upper end is rounded to fit over the shaft, while the lower end is perforated as indicated in the Fig. .- These pieces of board must-be carefully cut 186 MARKET DAIRYING so that the distance P is the same in all. If the holes at the lower ends are all in line the shafting is properly lined up. If not, the shaft needs readjusting. CALCULATING SIZE AND SPEED OF PULLEYS. The first thing to remember in determining the required size and speed of pulleys is the following rule: The speed varies inversely with the diameter of the pulley. Thus with the same speed of the engine, the speed of the main shaft becomes less as the diameter of the pulley on that shaft is increased. We usually speak of two kinds of pulleys: the drive pulley and the driven pulley. Where the engine drives the main shaft the pulley on the engine is called the drive pulley and that on the main shaft the driven pulley. When we refer to the main shaft driving the separator, then the pulley on the main shaft becomes the driver and ' that on the separator the driven pulley. In dairies there are two problems that present them- selves with respect to pulleys: one is to find the speed of the pulley when the diameter is given; the other is to find the diameter when the speed is given. 1. To find the speed of a driven pulley: Multiply the diameter of the driver by its speed and divide the product by the diameter of the driven pulley. Example: Diameter of engine pulley, 20 inches; speed of engine 200 revolutions per minute; diameter of driven pulley, 25 inches. 20X 200--25—160—=No. rev. per min. of driven pulley. 2. To find the diameter of driven pulley: Multiply the APPENDIX 187 diameter of driver by its speed and divide the product by the required speed of driven pulley. Example: Diameter of engine pulley, 20 inches; speed of engine, 200 revolutions per minute; speed of driven pulley, 200 revolutions per minute. 20 X 200 + 200 = 20 = diameter of driven pulley. CARE AND MANAGEMENT OF ENGINE. 1. It is essential to have all parts of the engine well oiled, using nothing but the best oil. 2. Keep the engine clean. The shiny parts should be brightened at least once a day. 3. Keep the engine well “keyed up.” At both ends of the connecting rod are keys, the purpose of which is to keep the brass boxes tight enough to prevent undue play. The “keying” consists in loosening the burrs next to the key and then tapping the latter lightly until the unneces- sary play is taken up. Care must be taken, however, not to get the brasses too tight or a hot box will be the result. “Pounding” is usually caused by not having the keys properly set. It is also caused by wet steam and water in the cylinder. 4. Keep stuffing boxes carefully packed to prevent leakage of steam. The packing should be treated with graphite or good cylinder oil and packed firmly around the rod, but it must not be too tight, otherwise power is lost in friction. If the rod has become scored or rusty, smooth it with emery cloth before packing. 5. The packing rings in the piston should be kept in good repair. The clicking noise sometimes heard in cylinders is due either to the packing ring wiping over 188 MARKET DAIRYING the edge of the counter bore or to its being too narrow for the groove in which it is placed. A ring is needed that fits this groove properly. If the packing ring is too small for the cylinder bore it should be set out by peneing or by tightening the setting out bolts. 6. When gumminess is noticeable in any of the bear- ings, remove same with benzine and use a purer oil. 7. When the engine “races” look for the trouble in the governor. 8. Thoroughly drain cylinder when not in use. This must be done in the winter to prevent freezing. THORN” ALISS Bottle Sealed with Metallic Cap. Metallic Milk Bottle Cap. INDEX. : Page Accounts, keeping.........++++- Acidity of cream........ Acid measures.........+eeeee0: Acid tests for cream Aeration of milk and cream.... 33 importance of........0.0eee 34 Albumen Albumenoids Appendix ....... ASB ices Babcock test...... ai Seats gaee ereee 42 apparatus for.......... sveae, 44 precautions in making...... 49 principle of..........05 eee 42 sample for.......sseeeeeaee 42 Babcock testers........sseeeeee 43 Bacteria, disease producing..... 21 lactic acid... .. eee eeeeeevee 20 taint producing............ a4 Bacteria in milk............00. 19 Barn air..... as Seas Lowe nemesis 29 Barn, sanitary...........4. 24, 154 Batri ‘yar disc cesiwcscsad seve ware « a 25 Bedding’ sssxs as oxciee es wrasse s 30 Boiler, care of........ eves 165 firing OF voce sscsieee seein ent 163 Boiler management............. 159 Boles sale. 6c sigaccscesaeys os 167 Bottle cases ....... isernieia tent COy AO. Bottle crates... see see cceecneee 89 Bottle: filler... ¢ssasevs sv awase es TA Bottle washer............00000- 83 Brine, @trengih,. @fs6% 05 ceecs cs. 139 Brushes: sissies wesisie's sae Gea 83 Burning, process of............ 163 Butter carton..........c eee e eee 128 working of........ Fa eadteeanite 124 yield Of: seveceveeveereee+ + 108 189 Page Butterfat, composition of...... 10 physical properties of...... 9 Buttermaking, farm............ 111 Buttermilk, composition of..... 18: food value of......... sisac 99: Buttermilk, skim-milk ......... 98 marketing of.............. 99 Butter print boxes............ 127 Butter printer.......... ties sway 125 Butter salting...........ecee00. 123 Butter worker........... eee ee LQG Can jacket...........5 seven tee 18 Cans: i dawias< weeledia o's +20. 78, 79 Casein caleees sails toaenedaias 12 Certified: milki.siiisae ciecaies a wes 154 Mennitlot. Ofyisnsvens ie cane 154 production of.............. 155 uses of........ Osis wg ese 155 Cheese, yield of.............0. 108 value of......... esha. iard) 2 Soop 108 Churning: sajalnees seamed: ead aa 117 GiMCUIE! « rescosie-a cea tisters'e de shuahe 126 influences affecting ........ 118 Bleps AGisaccusxbacosk yoeee 121 temperature in............. 118 CHURHS: cc nsau dees payee uw Paes i2t ClEARING: faictvirs ohssinsvantcesceaseats 126 Cold) Stofage ngs selene wean 62 Composition of milk of different breeds’. je-55)9 ss aja se case's 17 Compressor ........., Kaen Laeee 140 power required to operate..140 SIZE) Of se Lagasse i odinc heads 140 Cooler, cone-shaped............ 39 corrugated ........ceee eee 35 method of attaching.... 36 Hab Tat vd 6. she a: Oia 8 ances 38, 39 GOES 2.5 5 enews does Pees ea tas 35 Cooling, importance of......... 33 Precautiows Wi. ..c.cia~i.e. 40 190 Page Cooling milk and cream........ 33 value of prompt........... 34 With brine... 6. cseee cee cee 39 with ice, data on.......... 37 with pump,.......eeee eee . 37 Cottage cheese.............00ee 90 food value of............ ». OF making Of si «2 scdsec saws x 90 marketing of...........08- 96 packages for........seeeeee 95 VICI OB siiiscsie é otonias elondsestaie s 96 Cows; Cléatseuss sc cveve ceiver ce 25 health Ofj.¢ . + ssecseoe peers 28 Cream, bottling of............. 74 composition of ........+6.. 182 COOLELS: sewed cngad-e deans 35 pasteurization ...........6. 151 regulating richness of...... 56 retailing of ............005 73 | TIPENING 25s ecanges cranes s 111 control of .......0.06. 113 objects of ...... 111, 112 eterlere Tih wei ani eiw ny 114 Seales f0f* is neanescamiea oe 47 shipping of ............00. 78 standardizing of............ 59 test bottle for............. 45 testing acidity of.......... 117 value Of acieceawond viewed as yield of .. Creaming ....- Soe sap ay ausiesdcasseav’ ose centrifugal ..... as se oe ales 54 Cooley a8 fortes... iccesess 53 deep, cold method of...... 53 efficiency of ........ ee a8 6 54 processes of ......... veeee 62 Shallow pan ...sssseeeeeee 52 Dairy house.........seeeereees 129 construction of....... sean QD floor plans fories«caenvxnva 129 screening Of........eeeeeee 185 warming Of........eeeeeaee 134 Dairy thermometer............. 120 Delivery cases Delivery of milk......seeee0++ 77 INDEX Page Engine, management of........ 187 Fat and solids not fat........ 182 Fats, insoluble.............000. 11 Soluble ......ccccescereaes 12 Feeds, clean, wholesome....... 28 Firing, pointers on............ 164 FMGS) sess dvds aa vaiede 6 6 sees 31 Fore-milk oe. sssseseneecevenee 30 Tee DOK saieeers é eseraeselns esas ¥ 62, 63 Ice, cooling power of......... 178 cost of making............ 174 general uses of............ 174 necessity of.........00000. 172 SOUrCe Of oi ccs veda cgaeeess 174 SUPPly Of ja siete csecare de peeme x 172 Tee: cream si: iisies easiciare ad enamine. < 101 M@riO ti gjss a sedate’ x vdietlaeis 102 making: Of 2% esswena-e assesses 101 marketing of.............. 105 OVERFUN IN. cies scaawiee 105 packing of..........ss0e00. 103 packing can for............ 104 packing tub for............ 104 vanilla Ice house..... construction of BIZE Of tear se assets a istibeye we 174 TAjSCtOE ceincsiesas hare Siatacbud aetna core nea 161 Jackets, Telbs aces saaer antenna ay 78 Td 868 vs chinscdcdeweioande ee 148 Lemon ice cream.......eseeeee 102 DERMES. gs cadimiasdioasaG ieee ek 69 Mechanical refrigeration........136 Metric system...........e0e00 184 DIU so craters tewes ae iweniac ee cans care of, in home.......... 157 COTTEd occ ceeenoae sense 154 Colostrum ... cc cec cee e eens 14 composition of........ INDEX Milk coolers! i. ois.o: sige geigsige oo wis deliveries delivery wagons experimental data on pro- duction of clean....... 31 pasteurization of........... 151 physical properties. of...... 7 welailing? Of... <¢o ... cece eeeeee ..170 Well, construction of.......... 171 location Of......e++.0006+-L70