= 2 epithe ts Betas a auielatt te aPC Bay Renee ay a aire Ht ae ie elas i uk ae Ez ates ai Re Baeurente rat ALBERT R. MANi: LIBRARY a RNELL UNIVER! CORNELL UNIVERSITY LIBRARY Cornell University Library The original of this book is in the Cornell University Library. There are no known copyright restrictions in the United States on the use of the text. http://www.archive.org/details/cu31924073969788 Production Note Comell University Library produced this volume to replace the irreparably deteriorated original. It was scanned at 600 dots per inch resolution and compressed prior to storage using CCITT/ITU Group 4 compression. The digital data were used to create Cornell's replacement volume on paper that meets the ANSI Standard Z39.48-1992. The production of this volume was supported by the United States Department of Education, Higher Education Act, Title II-C. Scanned as part of the A. R. Mann Library project to preserve and enhance access to the Core Historical Literature of the Agricultural Sciences. Titles included in this collection are listed in the volumes published by the Cornell University Press in the series The Literature of the Agricultural Sciences, 1991-1996, Wallace C. Olsen, series editor. ‘VI ‘SUNY ‘HNATION FLVLG VMOT ‘PNIaGTING AUTVG re slergaIne ~ PRINCIPLES AND PRACTICE OF BUTTER-MAKING A TREATISE ON THE CHEMICAL AND PHYSICAL PROPERTIES OF MILK AND ITS COMPONENTS THE HANDLING OF MILK AND CREAM, AND THE MANUFACTURE OF BUTTER THEREFROM BY G. L. McKAY ann C. LARSEN, M.S.A. ” Professor in Dairying Assistant Professor in Dairying or THE Iowa STaTE CoLLEGE, AMES, Ia. FIRST HDITION FIRST THOUSAND NEW YORK JOHN WILEY & SONS Lonpon: CHAPMAN & HALL, Liwitep 1906 Copyright, 1906 BY G. L. McKAY anp C. LARSEN ROBERT DRUMMOND, PRINTER, NEW YORK PREFACE. THE science and practice of Dairying is constantly broadening. The different phases of this industry cannot now be mastered in so short a time as years ago, when comparatively little was known about the principles upon which dairying is now securely based. In connection with the teaching of dairying in the special four-year course at the Iowa State College, a set of lectures on advanced butter-making was prepared. In compiling these lectures special endeavors were exerted toward embodying the principles of butter-making, as well as the best practice of this art, in this as well as in foreign countries. The authors have studied, by personal observation and practice, the best and most progressive methods employed in butter-making in the principal dairy countries of the world, and have endeavored to incorporate these in this work. In con- nection with this practical phase of the question, the authors have endeavored to give such related scientific information as may be of interest and value. The general scientific knowledge has been absorbed from time to time from work done by various investigators at the different Experiment Stations. To all of these men who have searched for and discovered facts bearing upon dairying, the authors wish to express thanks and acknowl- edgment. The statistics and tables given in this work have been quoted from noted reliable authorities as indicated. The authors believe that the subject of dairying should no 111 iv PREFACE. longer be treated as one whole. For this reason such subjects as Testing Milk and its Products, Dairy Bacteriology, Cheese- making, and Technology of Milk and its Products, have not been treated comprehensively in this work. These lectures have been used, modified and changed, and under preparation for several years. At the present time the writers believe they are in such a condition as to warrant the publication of them. The authors admit that in our present state of knowledge it is in some instances difficult to distinguish well-established facts from those not so universally confirmed. It has been the object of the writers to give such information as is supported by the preponderance of experimental evidence. The authors are also indebted to the following parties for the use of electrotypes: Mower-Harwood Co., and Cherry Bros., Cedar Rapids, Ia.; Creamery Package Co., Waterloo Cream Sep. Co., and Iowa Separator Co., Waterloo, Ia.; Vermont Farm Machine Co., Bellows Falls, Vt.; Jensen Mfg. Co., Topeka, Kans.; Ox Fiber Brush Co., National Creamery Supply Co., International Harvester Co., Davis Cream Sep. Co., Borden & Selleck Co., and De Laval Sep. Co., Chicago, Ill.; Wagner Glass Works, and J. H. Monrad, New York, N. Y.; Burrell & Co., Little Falls, N. Y.; Empire Cream Sep. Co., Bloomfield, N. J.; Dairy Queen Mfg. Co., Flora, Ind.; Dairy Record, St. Paul, Minn., and W. D. Hoard, Ft. Atkinson, Wis. G. L. McKay, C. Larsen. Iowa State CoLtLece, Darry DEPARTMENT, CONTENTS. CHAPTER I. COMPOSITION OF MILK. ........0 2c cee ccc cece ceeeccccesscecccecace 1; Definition, Of MAM x: site ce c.ciare arciaeaty a saitars, «ig alere a aueia a celalgueremietardiece 2, Composition of Mak... csiccsciws eres ctinw wae vemedes see 3. Variation of Total Solids... 1.0... ee eee eee eee eee eens CA. Wat Oe sarc. sch Sausiezie vata ranges elnye soto teu wi Sa eat gg area gear econsiate: 5 Wate Milk x eraccresapaly eter eaee Coad. a awn aioe n Dae ela emE es 6. -Properties:of Kat........ncccaisaca a. cemasnewsae cea case He GY COTES OF BAG ie. o. case coserah-o-siaiacererotesese ci eteies nieve se acalniayateiarelaieis 8. Theories in Regard to Films Enveloping Fat-globules.......... 9:. Classes: of Pats::sc Blue! Milkirco io westseg!s ania eaurews 6 Ces iE A Ree same 4 aus 57 CONTENTS. vil PAGE Be Nello Mille j sich vieata acd he aiascn yn Otcige keen tae SEO TSS 57 Gs Ropy Miles, pss soeeo crbcis cadet enna cing a tenave d dalek asda De canaiw aad 58 7; Bitter Millkin «sian saciiie onstage outind’s wore dewieg o eae: Meat ae wean 58 8. Milk from Cows which have been in Milk a Long Period....... 60 9. Milk from Spayed Cows. .. 1.0.0... cece cece eet eee etnies 61 10. Milk from Sick Cows......... 0... ce ee cece eee een en eeees 62 CHAPTER VI. VARIATION OF Fat IN MILK... ........ 0000 c cece cece ee eee eeeeaee 65 1.. Individuality of Cows, 5 cs0s pve seule sewme seen egies eee ate 65 2. Breéd Of Cows)... 283 cease yemed bees Heme came ne ewe wes 67 3. Time between Milkings. ..........0.. 0.00.0 cece cece ee ee eee 68 4. “Manner Of MAUI 8s canis anendcarvenienn einaies athe Sautahl aes tha Wumueraile aeans 70 5, Milkine-machines). sso eicte ya sachs sleep aur Be earchos ¥ pig weer sie 70 6. Fore Milk and After Milk... 0... 0... ccc eee eee ener 73 Me FN BO OL COW sore ioe) sane aie av ehacwral ede tnuiite busin waynes WAIN ade Cash ES 74 8) LAGbatiOn PENOd.c seas tscne soos ates dang draigdle Wnala eee 74 0; Hood Of Cows) 46 sp-cignts soatsea mses oa reteun neha cals sane wuss 75. 10. Environmental Conditions. ............. 0c cece cece ee ences 76. CHAPTER VII. REcEIvING, SAMPLING, AND GRADING MILK AND CREAM............. 77 1. Receiving and Grading of Milk and Cream................... 77 A. Detection of Abnormal Milk Through the Senses. ....... 79 Bi, Usexot Acid Tests ices) .a vests oavwniare-srosiatieree anaiela euros 80 C. Use of Fermentation Tests. ..............0 cc ceeeeeees 81 a, Gerber and Wisconsin Curd Tests. .............. 81 D. Grading Milk by Heating..................0-2 eee eees 82 E. Use of Babcock Test and Lactometer................. 84 2. Necessity of Good Milk... 22.2... ccc ccc cece ence eens 89 8. Sampling Of Milks. ois cweron gantnd sade nacmems anlar cuaawardeians 93 4. Sampling-tubes.c sascsawhes Gonsemes vases eee wees es 94 5. Sampling Churned Milk... 2.0.0.0... 2 cece cece cece ee eneeee 96 6; -Frrozerd Milks s. 2.3552 asa aecie ecdsons o.oo Dear WAAR Basalt arent wean 96 7. Sour and Coagulated Milk... ......... 0... ccc cece cece ee eee 97 8. Apportioning Skimmed Milk... ........ 0.0... cece eee eee eee 97 CHAPTER VIII. COMPOBITE ‘SAMPEESS oa: eatcdsouie selnewenien saaw etiam estes vasew tae 99 1, Definitiony.2.4 9 same cniodiscmiae Sa 9G-RS Saw breieeidreaueieteie crow wame ace 99 2, Wihento Sain ples ssc cswide ea a acd eae eeaunise Senos macents 99 viii CONTENTS. PAGE 3. Kind of Preservatives to Add. 2.2... ccc cece cece rece eee 99 4. Arrangement of Composite Samples... ..........-.00e0e eee 102 5. Care of Composite Samples. ... 0.0.0.0... 0 cece eee e rece eens 102 6; Average Samples, g...iw.c cs gees sues ahaa a a dee See RE 104 7. Composite Sampling without the Use of Preservatives......... 104 CHAPTER IX. CREAMERY CALCULATION: cass 08d osu seot's gawA caweeh Ga wee Deu areas 8 105 1. Finding Average Percentage of Fat.. .............0 0000-000 105 2. Calculation of Overrun... 0.0.2 ccc eee ene eee eeee 107 A. Thoroughness of Skimming... ...............0000000- 108 B. Completeness of Churning.... 0.0... .. ese eee cence eens 108 C. General Losses in Creamerics. .........-..0e00eeeeeees 108 D. Composition of Butter Manufactured.................. 108 8. Calculation of Churn-yield. .......... 0.0.0... cece eee eee 109 4, Calculation of Dividends.............0 2. cece cece cence ee eees 109 5, Cream-raising Coefficient. ... 0.0.0.0... ccc cee cc eee cece eenes 113 6. Statement to Patrons... 0.0.0.0... cece cee eee eee eee 113 7. Paying for Fat in Cream as Compared with Paving for Fat in Milk 116 8. Degree of Justice in Paying Cream Patrons More per Pound of Fat than the Milk Patrons.... 2.00.0... ccc cece cece ee eee 117 CHAPTER X. Heatinc MILK PREVIOUS TO SKIMMING............00cceseeceeceees 118 1. Reasons for Heating. . .........0. 00.00. cece ceeeceeeceeeeas 118 2. Advantages of Warming Milk to High Heat Previous to Skim- DMD Bs. sis is a Ghnarei ius 4 Hay 24 GAG sae SEN Se cies sana 119 3, How Heated ss sicetc sede s iced ciate s new ele dees awe rena tien 121 CHAPTER XI. SEPARATION OF CREAM. .... 0.0.0 - eee e cece ccc n sec e cn seceeeuaeenes 123 1, Gravity Creaming. ... 20.0.0... cece cece ccc n cence cee ees 123 A. Shallow-pan System... ..........0.00ccceeeeeceuees .. 123 B. Deep-setting System... ........0.0. 000 cece cece eee eee 124 a. Probable Explanation... ................00000: 126 C. Water-dilution Cream (Hydraulic). ...............2.0. 128 2, Centrifugal Creaming............. 00.00. c cece cen ceeeeeeees 129 Ay Advantages: ae sce cr see vouch caw osu bon oad eee ae s 129 B. History of Centrifugal Separators. ..............0-005- 130 C. Modern Separators. ............0cccecceeeeseceseeecs 132 D. Classification of Separators..........00.cceeseeeeeeees 133 CONTENTS. ix PAGE FE. Process of Separation... 2.0.0.0... ccc ccc eee eee ees 134 F, Relative Amount and Richness of Milk and Cream Obtained scices cucios eee eats WERE eee ene ed 137 a. Regulation of the Cream or Skimmed-milk Screw. . 137 6. “Rate of Inhl6w:..6. conv ecanscene samen cue 138 C2, SPCC: ch a-audwiion wees saey soueas eee eae Ses 138 a: Temperatures 0. ae csusae sine nenaced qanie smaiaes wines 139 G. Conditions Affecting Efficiency of Separators........... 139 u. Manner of Heating Milk....................... 139 b. Condition of the Milk.................... se reales 141 c. Overfeeding the Separator..............000 00005 141 d. SPGOd isi spe taaateniae Lee eat eden eed mee Cate 142 e. Steadiness in Running.................00000005 143 j. Thickness of Cream...................00000008 144 g. Slush in Bowl... 00... eect ane 144 h, General Remarks. ... 0.0.0.2... e cece eee eeee 145 CHAPTER XII. FARM SEPARATORS) «io: 6c 5606: 0 ede ioe er elesei ed does wie anes 9S Gide ecb ee 146 1. Introduction of Farm Separators... ....... 0.02 eee eee 146 2. Reasons for Introducing Farm Separators. .............00005 147 3. Objections to Farm Separators, .............0... eee eee eee 152 4, Thicknéss*of (Creams. ci. oisuik ssp oreaveidi aomean Sadun weak auras 152 5. Power for Farm Separators... ............0 ese e ee cee eens 155 6. Care of Cream on the Farm.............. ccc ee eet entree eee 158 7;. Disposition Of Cream..9 2/3905 «wars ane vexmew eae vaResea ee’ 167 A, Shipping of Cream, ............ 0.0.0 c cece eee eee eee 169 B. Making Butter onthe Farm...............000.-ceeeee 169 CHAPTER XIII. PASTEBURIZATION:. § s:gis oda se ee eeu vacee sede oted taney saa Rea 173 1, Definition, occas sere ccna vad Suthers stiscion teamed Sadek eden 173 2. Methods of Pasteurization. ........... 0... cee eee eens 173 Ay INCEMMITED Es wists Sie aes eeu derate Sem ees oad 173 Bi ContimuGussiae see's says sects e-onion aes ea xaee vider sense 174 3. Selection of Pasteurizers. ........ 0... cece cece eee ete teens 175 A. Durability and Capacity. ....... 0.0... ccc cece eee 175 B. Economic Efficiency... 02... . cece cece cece et ee eens 175 a. Heating Suriaces.: os ssneec x awed vanes dete sons 176 b. Degree of Adhesiveness.............-00000eeeee 177 c. Thickness of Layer of Condensed Steam.......... 180 d. Difference in Temperature on Each Side of Heat- ing Surface, «.< s6c0 ssa. ecees ea wer scien canes 181 x CONTENTS. PAGE e. Proper Utilization of Steam Turned into the Pas- POUTIZER, j.5 oikaed causa MES BOATS RG ee wae ae 182 C. The Cost of Pasteurization. ............-. 00sec eee eee 183 D. Advancement of Pasteurization. ...........-.+2-+++55- 183 E, Advantages of Pasteurization............ 2.6. .+0-eeee 184 F. Disadvantages of Pasteurization............+-.+2-+e05 186 CHAPTER XIV. CREAM-RIPENING, ..2:44 6% fee 2 oeeeees BSR EE PRR TE RES Ge se oe e te Se oy 187 1. Definition... sccaavisae tees es vader ses 404 eORee ieee ee 187 2. Objects of Cream-ripening. ... 2.2... 0. 187 A. Production of Flavor and Aroma... .........+-++++-0+- 187 B. Increases the Churnability of Cream................... 191 C. Increases the Keeping Quality of Butter............... 192 3. Ripening Temperature of Cream. ...........- 000s esse eee 194 4, Amount of Starter to Add to Cream..................-00006- 196 5. Stirring of Cream during Ripening. ..................-..005- 197 6. Natural “Ripening: oyun desea eee es ees akmew ee Mane ee 198 7; Artificial Ripening: vss 5 yes o834's 4 eaies Wales s Pues Samlemesee 199 8. Ripening Cream when Churning is Done Every Other Day..... 201 9 Mixing Of Cream cars, 205 ee jets deacnigdel be: cohagoa ca Seger Bisve te eas ewe Sees 202 A. Quality of Cream......... 00... c eee eee eee sone & 203 B. Wind of Markets, siswarsanccaaieeg ey es pe eee es pees 204 C; Amount: of Cream: cs a04 jo iv ee see ee ec sow ss tee vealeks 204 D. General Creamery Conditions...................00000- 205 10. Examining and Testing Cream for Acidity during Ripening... . 205 Marin’ s Best os ic- Ge saa inedog Ned anaiigna PER ee ae TS res oeleets 206 12. Farrington’s Test)... s. 287 12., Mammen OL Jai S110 8) sa sce caae. b cctsvcaeuisvavnsace erintl 8 @chvaagliasespeghsl Wi atiinde te 290 As, SBO yircgied< scutes tte cant cys amseese taoanaite itaancg endlsactveradla et woaseavens 290 BB NTN. OF sic geod sl opehia nausea eceiias eed arualaG: eens eaueIRS es 290 CY Color cc 2. mains ees on Roe Reed oe eee eR awe scree ealsiale « 291 De RAM Gs aoa seis ctiee beside aula Sim ese Sig Sites el uhaganain aed epee a cia A ES 292 BO. S616 jcseiaa due aoa meet Sam sapesaee Gane aM eS aaa 292 8. Classification of Butter... 00.00... ccc cee ete cence ne eee 292 4. Grades-ol: Buttera v5 xv ease uae verine veneer eds kewsln ae is 293 6. Export: Butters... goss: sassiacd as anit ke ds dee Gate emex saamee 296 APPENDIX. J. A Laporatory CoursE IN Farm Dairyine CoNSISTING OF Four- TEEN [EXERCISES ON HANDLING, SEPARATING, AND TESTING MILK AND CREAM UNDER Farm ConpiTions. A FEW OF THE EXERCISES ARE DEVOTED TO THE MANUFACTURE OF BUTTER ON AOMALIY SORDB oan tetawgpeen a Grasse quien ontaoswinies ane bier 299 II. Lecat Stanparps ror MitkK—Darry LAws.............+ sess 314 III. Metric System or WEIGHTS AND MEASURES WITH TABLES FCR CONVERTING THEM INTO CusTOMARY UNITED StaTEs Equiv- ALENTS AND THE REVERSE............ 0000 ccc eee eect tenes 315 BUTTER-MAKING. CHAPTER I. COMPOSITION OF MILK. Definition—Normal milk is a liquid secreted in special glands of all females belonging to the mammalian group. It is composed chiefly of water, proteids, fats, sugar, and minerals. Coloring-matters and gases and some organic acids are found in small quantities. All normal milk from the different classes of animals, such as mare, buffalo, goat, ewe, ass, and cow, has a general resem- blance in that it all contains water, fat, proteids, sugar, and ash. But milk from different animals varies in the relative proportions of its constituents. The chemical and physical properties are not alike. Human milk, when treated with’ half its volume of ammonium hydrate and the mixture kept at a temperature of 60° centigrade for about twenty minutes, assumes an intense red color. Cow’s milk turns faintly yellow if treated in the same way. This test was reported by Unikoff, of St. Petersburg, at the mecting of the Medical Section, Royal Academy of Medicine, in Ireland. The various kinds of milk also differ from each other in their behavior towards rennet. Richmond has divided milk into two classes: Class I includes milk from the ewe, buffalo, goat, and cow. When rennet is added to the milk from these animals, the casein coagulates into a firm curd. Class II includes human milk, milk of the ass, and mare. When rennet is added to the milk of these animals, a soft curd or none at all is formed. The latter class seems 2 BUTTER-MAKING. to include the animals without horns, while the first includes those with horns. As the cow’s milk is used chiefly as a food, it has been subjected to more extended and more careful investigation than the milk of other animals, and, as a consequence, more definite knowledge has been obtained concerning its com- position, properties, and uses. The succeeding discussions have reference to cow’s milk, if not otherwise stated. Composition of Milk—It is impossible to get accurate figures on the composition of milk, as each of the milk con- stituents is subject to fluctuation from various conditions, such as individuality of cow, breed, season of the year, lacta- tion period, milking, and environment. The average composition, as determined by 200,000 analyses reported by Richmond as follows: WoateDisscsccsaecwr ere cara trnacdtaan S710 Hatin Gea oo ew pe edwaeboaa ean. on00 Milk-sugar. ...............0. 2000000002. 4.75 Enos pee : 4 The composition of various kinds of milk is given by Konig as follows: No. of 5 Casein Milk- Specifi sera Water. Fat. Pe ae sugar. | Ash Uravity Human.......-- 107 87.41 | 3.78 2.29 6.21 .81 | 1.0270 Mare. .....-...-+- 50 90.78 | 1.21 1.99 5.67 .35 | 1.0347 Buffalo. ......... 8 82.25 | 7.51 5.05 4.44 -75 | 1.0350 ASS scene sus ciries 7 89.64 | 1.64 222 5.99 -51 | 1.0345 Cow. 2. ai severcs 793 87.17 | 3.69 3.55 4.88 .71 | 1.0316 TW). oisie den Gary 32 80.82 | 6.86 6.52 4.91 -89 | 1.0341 GOAb 5 fav ccceimoneseus 38 85.71 | 4.78 4.29 4.46 -76 | 1.0328 SOW ce ey asco ec 8 84.04 | 4.55 7.23 3.23 | 1.05 | 1.038 Bitehc.s e.qngeser 28 75.44 | 9.57 | 11.17 3.09 .73 | 1.035 Elephant........ 3 79.30 | 9.10 2.51 8.59 .50 | 1.0313 Hippopotamus, . . 1 90.43 | 4.51] ...... 4.40 ll Camel, .......... 3 86.57 | 3.07 4 5.59 -77 | 1.042 Llama.......... 3 86.55 | 3.15 3.90 5.60 .80 | 1.034 COMPOSITION OF MILK. 3 Variation of Total Solids—-As applied to milk, “Total Solids,” is a term that includes fat, casein, albumen, sugar, and ash; in other words, all the milk constituents except the water. ‘Solids Not Fat” is a term often used, and includes the casein, albumen, sugar, and ash, or all the milk constituents except water and fat. ‘‘Serum” isa term used to designate all the milk constituents except the fat. The fat is the most valuable constituent of the total solids. The variation in the total solids of milk during the summer months is shown in the table quoted below from Dr. Van Slyke of Geneva, New York: Month. Per Cent Per Cent of of Water. Total Solids. Mays esi aneicestoles 87.44 12.56 JUNC te ona knees 87.31 12.69 DU socio ttxveesia/ tease 87.52 12.48 August........... 87.37 12.63 September........ 87 13 October, .......... 86.55 13.45 Dr. Van Slyke also studied the effect of the lactation period upon the total solids in milk. A herd of fifty cows, calving in different months of the year, was used in the experiment. The per cent of total solids of this herd seems to average a little high all through the ten months. The total solids were found to be 14% during the first month, decreasing to 13.47% during the next two months, then gradually increasing with the advance of the lactation period. In the tenth month the average total solids was 14.83%. Pingree, of Pennsylvania, reports having found normal milk from a cow, which contained 17.01% total solids. Sherman * reports a very high average total of the milk solids. He treated the milk from thirteen cows, and found it to contain on an average 18.03% of total solids. Konig reports a minimum of total solids of 9.31%, a maximum of 19.68%, and an average of 12.83%. The average total solids quoted above from Richmond is 12.90%, which agrees closely with K6nig’s results. * Journ. Am. Chem. Soc, 4 BUTTER-MAKING. The difference in total solids of milk from some of the leading breeds has also been studied by Dr. Van Slyke, and the results are as follows: Breed. aWeret, ‘Total Solids. Holstein... ....... 88.20 11.80 Ayrshire.......... 87.25 12.75 Shorthorn... ...... 85.70 14.30 Devons: e520 e034 85.50 14.50 Guernsey.......... 85.10 14.90 Jersey............ 84.60 15.40 The maximum and minimum amounts of total solids men- tioned above are abnormal cases. The normal variations of the solids in milk are within comparatively narrow limits. For this reason the minimum standard for total milk solids, in states where dairy laws are in force, is fixed by law. Usually 12% is the minimum. Water.—From what has been said above concerning the total milk solids, it will be seen that water constitutes by far the largest portion of milk. It is quite uniform, and in milk from a mixed herd the water seldom falls below 86% and seldom exceeds 88%. Variations ranging from a little less than 80% to a trifle over 90% are on record. But such varia- tions must be looked upon as occurring in only a very few special cases. It has often been asserted that cows in the spring of the year, when they are pasturing on new grass, or feeding on other succulent foods, yield milk which contains an excess of water. Under such conditions there is a tendency for cows to pro- duce milk with a water content a trifle higher, as has already been shown by the figures quoted from Dr Van Slyke. As a rule this is much overestimated. It is even a common occur- rence to hear creamery operators say that their “soft” or “slushy ” butter, in the early spring, is due to the excess of the water present in the milk. This particular phase will be dis- cussed further under the heading of ‘‘ Fats in Milk.” The question has often been raised: Is the water in milk COMPOSITION OF MILK. 5 the same, or any more valuable than water obtained .from other natural sources? The water in milk, so far as known, is transuded from the blood-vessels in the udder into the milk glands. It is so perfectly mixed with the other milk con- stituents, and holds the milk solids in such perfect emulsion and solution that it would seemingly be impossible to prepare milk so perfectly by artificial means. However, a substance. is prepared by Jacob C. Van Marken, Neuweid, Germany, which, when added to water, produces a substance similar in appearance to watered skimmed milk. The preparation is named “Kalberrahm Vita.” The first name literally means calf-cream. It has a syrupy consistency, and in appearance resembles light-brownish molasses. It is sold in tin cans, and recommended highly for calf-feeding when mixed with skimmed milk. When mixed with water, it is recommended highly for hog-feeding. Water distilled from milk has the same appearance as ordi- nary distilled water. It is clear and colorless. The chemical reaction when phenolphthalein is used as an indicator, is neutral, the same as that of ordinary distilled water, even when dis- tilled from milk in which acid has developed. But there is ' a considerable difference in the taste and smell. This indi- cates that some of the volatile substances are distilled over with the water. The probability is that these flavoring substances are so closely associated with water in milk that they are in- separable, and that the only place where this water can be prepared so as to assume these qualities is in the cow’s udder. The conclusion would then be that the water in normal cow’s milk cannot be distilled and substituted again by natural water and the product retain its normal good flavor. Fat in MILK. This is by far the most important constituent of milk, especially to creamery operators. It exists in the milk in sus- pension, in the form of globules so small as to be invisible to the naked eye. According to the best authorities, fat- 6 BUTTER-MAKING. globules, at ordinary living-room temperature, are present in milk in a liquid form. Cooling the milk to a very low tem- a. Skim milk. oY a oO «“o oo 6 Pg. 1h fo) 0° : 02 0° ie “Oto 00, 9 2° Oro, 70 me P00)" eee ks . 00? no ross © "ORO 30 e. Cream. & ° 020 es h4 (e) % o ‘ ° ee: eo 'O, oy 09 ¢ 08% G0 Os Los SRO 904 Fic. 1.—Microscopical appearance of different kinds of milk Magnifi 300 times, (U.S, Farmers’ Bul. No. 12) ae perature (about 50° F.) hardens them. When the globules are caused to unite, as in churning, they also solidify. The size of the fat-globules is very minute, and varies con- COMPOSITION OF MILK. 7 siderably, according to breeds, individual cows, and the stage in the lactation period. The globules in the milk from the same cow also vary a great deal. Lloyd found that fat-globules in Jersey milk to be from 8 to 12 micro-millimeters in diameter. Very few were less than 4 micro-millimeters (a micro-milli- meter is zyy_ millimeter, or s¢y7 of an inch). The majority of the fat-globules in milk from Shorthorn cows measured from 6 to 8 micro-millimeters in diameter. According to Fleisch- mann, the size of fat-globules varies between 1.6 micro-milli- meters and 10 micro-millimeters in diameter. A Danish in- vestigator maintains that the diameter of fat-globules is between .0063 and .00014 millimeters, and that 1 cubic centi- meter of milk contains from 2.6 to 11.7 million globules. He also asserts that a reflection of the light renders it very difficult to get the proper size of the fat-globules, as the light tends to make the globules appear larger than they are in reality. It has been maintained by some that the larger fat-globules contain fats which are different from those contained in the smaller globules. But this is by some investigators considered to be a matter of conjecture. Most authorities now believe that there is no difference in the kinds of fat of the different- sized globules, even though some experiments * show that fat composed of larger globules has a finer flavor, and a little more oily appearance. From what has been said, it will be seen that the minute- ness of the fat-globules is almost inconceivable. They were first discovered in 1697 by A. von Leeuwenhoek. The minute state of division, or the form of emulsion in which they exist in milk, renders it easy to digest when consumed as a food. Properties of Fat.—The specific gravity of pure butter-fat at 15° centigrade is .93002. The refractive index of butter- fat at 22° centigrade is on an average 1.459. The melting- point of pure butter-fat, as now determined, varies between 32° and 37° centigrade. (90° F. and 99° F.) * Gembloux, Belgium, Creamery Jo., London, No. 8, Vol. I. 8 BUTTER-MAKING. When pure butter-fat is rapidly cooled, it solidifies into one solid mass; but if allowed to cool gradually, part of it solidifies, and part of it remains a liquid longer than other parts. This seems to indicate that some fats with a high melting-point separate out from the fats with a low melting-point. This behavior of pure butter-fat is not well understood, as it con- tradicts the now accepted theory that the different fats are in chemical combination with each other, rather than a me- chanical mixture of different glycerides of fat. Glycerides of Fat.—By this term we understand that the fatty acid radicals are in chemical combination with the glycerol (glycerine) radical, thus: Fatty acid radicals, Glycerol radical. C4H702 (Butyric) C3Hs5 } CigH3302 (Oleic) | CigH3302 (Stearic) The chemical formula for glycerine is: Hydroxyl] groups. Glycerol radical. OH C3Hs OH | OH Comparing these two formulas, their difference and simi- larity are easily observed, and the reason why the term “‘Gly- ceride of Fat” has been applied to such a compound is evident. Condition of Fat—Whether the fats in milk exist in chem- ical combination, or whether they exist as glyceride of butyrin, stearin, olein, etc.,in the form of a mechanical mixture, is a question in dispute. If they exist in the latter form, the com- position of the different fats must be thus: Butyrin. Olein. Stearin. C4H702 CigH3302 CigH3502 C3Hs {CsH702 C3Hs jCisHssO2 C3Hs } CigH3502 ete., { C4H702 { CigH3302 CigH3502 COMPOSITION OF MILK. 9 and the total fat made up of a mechanical mixture of these and the remainder of the fats in butter-fat. Richmond and other authors believe that fat probably exists in milk chemically, as first mentioned and illustrated; because, if the fat were a mixture of glycerine tributyrate with other glycerides of fat, butyrin or glycerol tributyrate could be dissolved out by the use of alcohol. But this is not the case. Moreover, if butyrin existed separately in milk, it would be possible to distill it off under reduced pressure. This cannot be done. Theory in Regard to Films Enveloping Fat-globules.—The extreme minuteness of the fat-globules in milk renders it almost impossible to determine by direct microscopical observation whether there is a membrane around each globule or not. Fleischmann and Lloyd assert that, so far as they were able to detect, there is no real membrane surrounding each globule. The theory generally accepted in the past was that the only film surrounding the fat-globules was simply due to sur- face tension, or to the fact that the molecules of the fat have a greater attraction for themselves than they have for the molecules of the serum, in which they are held in suspension. In support of this two things are considered: (1) The natural milk-fat may be removed from milk and artificial fat substituted in its place. The resultant milk has characteristics similar to milk containing normal fat; that is, the emulsion which milk forms with the artificial fat is ap- parently like that formed with the natural fat. (2) If there were a special albuminous membrane around each fat-globule, cream should contain a higher percentage of albuminoids than milk. This, Richmond maintains, is not so. Dr. Storch concludes from extensive researches that there is a gelatinous membrane enveloping the fat-globules. His conclusions are based mainly upon the first three reasons given below. The other facts mentioned also support his conclusions: (1) When milk has been stained with ammoniacal picro- 10 BUTTER-M AKING carmine, and the cream washed with water until it is free from milk-sugar, a stained layer is present around each globule. (2) He has succeeded in isolating this gelatinous substance from cream and butter. Owing to its existence in these two substances, he assumes that it is also present in milk. (3) When ether is added to milk, the fat globules dissolve with difficulty, unless some alkali is added to the milk first. (4) Bichamp maintains that when ether is added to milk the fat-globules are enlarged due to the ether passing through the supposed membrane by the process of osmosis. He con- siders this fact sufficient to prove that there is a membrane encircling each globule. (5) Butter containing 85 to 86% fat is asserted by Rich- mond to have the same consistency as cream containing about 72% fat at the same temperature. The solidity of butter is due to the close proximity of the fat-globules. Now, if cream with less fat has the same consistency as butter, the proximity of the fat-globules must be equal to that of the butter; this would indicate that there is a membrane and that this membrane increases the size of the fat-globules. (6) The fact that cream separated by centrifugal force is more easily churned than cream of same richness separated by gravity methods, would also be explained if the fat glob- ules in milk had such a membrane surrounding them. This membrane, or what is believed to be a membrane, Storch has isolated and analyzed. He finds it to consist of 94% of water and 6% of proteid. The reasons deduced by Storch are strong; and the behavior of cream and butter renders it probable that there is such a membrane enveloping each globule of fat. CLasses OF Farts. There are two great classes or groups of fats present in the butter, namely: (1) Volatile and Soluble, (2) Non-volatile and Insoluble. COMPOSITION OF MILK. ll It was previously stated that little is known concerning the way in which the fatty acids are combined with glycerine in the milk; but, for the sake of convenience, the fats will be referred to as if they exist as separate glycerides of fat. The terms “ Volatile’? and ‘“ Non-volatile” are applied to the glycerides of fat, or to the fats as they exist in butter. Strictly speaking, this is not proper, as they do not assume the volatile characteristics until the glycerine separates from the fatty acids; it is only then that the latter becomes volatile. Volatile Fats.—The first group, or the volatile fats, include butyrin, caproin, caprylin, caprin, and laurin. Butyrin is the one present in the largest proportion. Laurin and caprin are partially non-volatile. Butyrin is the most important fat belonging to the volatile group. It is the most important quantitatively, and also qualitatively. So far as is known, butyrin is the least stable of any of the butter-fats. Under normal conditions, so long as the fatty acid remains in com- bination with the glycerol, it is not volatile nor soluble in water but as soon as separation takes place, due to the action of micro-organisms, or to the effect of light and air, then it becomes volatile, and escapes in the form of gas. According to the mass of evidence, these factors are the chief causes of rancidity in butter. It is also claimed that these volatile fats have the special properties of absorbing odors and gases to a greater extent than any of the other fats. This absorption takes place when fat comes into contact with the undesirable taints. For this reason it is essential that milk, cream, or butter be kept away from any foreign undesirable odors. These undesirable taints may also be imparted to the fat before the milk is drawn. If the cow is fed on undesirable food such as turnips, onions, garlic, etc., the milk from the cow assumes undesirable char- acteristic flavors, which can-easily be recognized in the finished product. On the other hand, such foods as well-cured sweet- clover hay, and bran, seem to impart desirable flavors to milk and butter. 12 BUTTER-MAKING. The presence of these volatile fats in butter is quite uniform, and is a distinguishing feature of pure butter-fat. The detec- tion of adulteration of butter with foreign fats is based chiefly upon the presence of these volatile fats. The characteristic desirable flavor of butter is also believed to be due to the pres- ence of the volatile fats. The volatile fats vary but slightly during the different seasons of the year. They are present in the greatest proportion during the spring and early summer months, when cows are fed on grass, and also during the early stage of the period of lactation. They decrease gradually as the lactation period advances. About 8% of the total fats in milk is volatile fats. Non-volatile Fats.——This group constitutes about 92% of the total fats in butter. Chemists now agree that palmitin, stearin, olein, and myristin are the most important ones to be considered, as will be seen from the table quoted from Rich- mond. These non-volatile fats are of special importance, as the relative amount of each of these fats largely causes the varia- tion in the hardness and softness of the butter and butter-fat. The melting-point of these different fats varies according to the different investigators: olein is a liquid at ordinary tem- perature and melts at about 41° F.; stearin, on the other hand, has a melting-point of about 150° F.; palmitin also has a high melting-point, namely, about 142° F.; myristin melts at about 129° F. Olein has been found to be present in the greatest pro- portion during the spring, when cows are fed on grass. When cows are fed on normal dry food, as in the winter time, it is present in a much less degree. This, together with the small increase of volatile fats, is the cause of the softer butter so frequent in the spring. The hardness of the butter in the fall or winter is due chiefly to the presence of a slightly increased amount of the fats, with a high melting-point, as mentioned above. From what has been said above, one is led to believe that, COMPOSITION OF MILK. 13 by melting a sample of butter which contains these different fats, the fats with a low melting-point would melt first, and leave the remainder in an unmelted condition. Such is not the case. Butter-fat in this respect behaves a good deal like different metals with different fusing-points. When they are melted and mixed together, cooled and then remelted again, they assume a common melting-point. It is the same way with butter-fat. It melts at a temperature of 91° to 96° F. As the body temperature of cows (about 98° F.) is above this temperature, the fat globules are present in the milk in liquid form when milk is first drawn. A peculiarity about these fat-globules in milk is that the milk and fat may be cooled down below the melting-point of the fat of butter without the fat-globules in milk being solidified. It requires'a tem- perature of between 60° and 78°F. before the fat-globules in milk begin to solidify. When these small fat-globules are caused to unite, as during the churning process, they solidify at higher temperature. This behavior of the fat in milk evi- dently must be due to a relative change in the position of the molecules of fat during the process of cooling and warming. No definite explanations, so far as is known, have been given for this condition of the fat. The non-volatile fats found in butter-fat are practically the same as those found in other animal fats. Composition of Butter-fat—aIn his ‘“ Dairy Chemistry,” Richmond gives the following composition of butter-fat, repre- senting the mean results obtained by different observers: ; r Butyrin. ........ 3.85% 8% Volatile......... | Caproin,, ....... 3.60% Caprylin,........ 55% Fat...... Caprin.......... 1.9% Laurin, ......... 7.4% sung Myristin, ........ 20.2% Bay Nem-yolnlleasie 4 itn cas noe 25.7% Stearin.......... 1.8% 14 BUTTER-MAKING. Richmond also gives the percentage of glycerine and fatty acids in each of the different fats, as follows: Butyrin. .. 3.85% yielding 3.43% fatty ands and 1.17% lyeerine Caproin... 3.60 3.25 .86 Caprylin. 55 “ec 51 “ “ec 6c 10 “ce Caprin.... 1.9 “1.77 os fe OE BI ae Laurin. ... 7.4 6.94 me ee EE DOF ih Myristin. .. 20. 2 ce 19.14 ce “cc oc 22S oe Palmitin .. 25.7 ft 24.48 ae ce 6 2.91 ae Stearin.... 1.8 nf 1.72 a we EE AG e Olein..... 35 «33.60 : £3.39 as 100 94.84 12.53 Proreips (ALBUMINOIDS). The proteids of milk are present partly in solution and partly in suspension. They are present in a very complex chemical form. Some of the chemists reckon as many as eight different albuminoids or proteids in milk. Duclaux claims that there are only two kinds of albuminoids, the coagu- lable, and non-coagulable casein. He has, by the use of a fine filter, been able to separate the fat and the coagulable from the rest of the serum. The amount of coagulable casein is claimed to vary considerably, and seems to depend upon the amount of lime phosphate present. The filtrate which Duclaux obtained from filtering the milk was clear and colorless, which proves that the removal of the casein was quite complete. In order to remove casein from milk, a special filter (Chamber- land) is employed. Owing to this fact, we may consider the casein to be present in suspension or semi-solution. Noted chemists, such as Babcock, Van Slyke, Duclaux, Storch, Ham- marsten, Ritthausen, and Richmond, disagree upon the num- ber of albuminoid substances found in milk, and upon the chemical behavior of each. For all practical purposes it is safe to mention two, namely, (1) casein, and (2) albumen. Those two substances, as all agree, are present in milk, and constitute practically all the COMPOSITION OF MILK. 15 albuminoids in milk. But after these two have been separated from milk a slight precipitation can be obtained by treating the filtrate with alcohol. This has been called albumose and also lactoglobulin. From this resultant filtrate can again be separated a very small amount of material containing nitrogen. Dr. Babcock has obtained a substance from milk called fibrin. These latter substances, however, are present in minute portions, and are believed by some of the best scien- tists to be the same as the albumen, and their presence in the filtrate is due to incomplete precipitation of the albumen in the first place. Casein.—Casein is by far the most important of all of the albuminoids. It is the substance which forms the curd in cheese-making. In fresh milk, as is now understood, it is in chemical combination with lime salts. It is on this account that fresh milk shows the amphoteric reaction, which will be explained under the “ Properties of Milk.” The coagulation of casein by the addition of rennet or dilute acids is thought to be due to this union between the casein and lime. Fleisch- mann refers to this as the ‘‘ caseous matter” of milk. The viscosity of normal milk is believed to be due in a large meas- ure to this condition of casein in milk. It causes the casein to be present in a colloidal condition. When milk coagu- lates by natural or by artificial means, the union between the casein and lime phosphate is largely broken. Casein and albumen differ in composition, in that the casein contains phosphorus and less sulphur than does albumen. Fleischmann maintains that a substance called nuclein is associated with casein, and is not found in albumen. Casein is precipitated by the use of rennet and dilute acids, and coagulates spontaneously, due to the acid formed in the milk. The precipitates formed by the use of different pre- cipitating agents are not alike. The curd coagulated by ren- net contains more fat and calcium phosphate than the curd does which is precipitated by dilute acid or soured sponta- neously. If milk stands at air temperature for any length 16 BUTTER-MAKING. of time after milking, the caseous matter (or the nitrogenous matter combined with lime) tends to separate. The caseous matter of milk is not completely precipitated by heat, although heat partially destroys the union between the casein and lime. This destroys the action of rennet. Instead of getting a smooth solid coagulum, a more flaky precipitate is obtained. For this reason milk for cheese-making should not be heated to a high temperature. By heating milk in a glass flask to a high tem- perature, and letting it stand for a time, it will be found that a mineral precipitate has settled to the bottom. This pre- cipitate is believed to be a lime phosphate, which, previous to heating, was combined with the casein of the milk. By adding calcium chloride (CaCl) to milk which has been heated, its normal condition towards the action of rennet is again restored. Albumen.—If the casein is removed from the milk by precipitation, and then filtered off, the filtrate will contain a substance which will precipitate when boiled. This is albumen, and is similar in character to albumen from the white of an egg. It differs from casein in that it is not precipitated by rennet or acids, but precipitates on heating. It does not contain any phosphates, but contains a comparatively large amount of sulphur. As the albumen is soluble in rennet and dilute acids, it can readily be seen that it is retained in the whey obtained in cheese-making. When albumen is present in small quanti- ties, as it is in normal milk, heating does not completely pre- cipitate it, unless the casein or curd is first removed. If, on the other hand, albumen is present in excess, as is the case in colostrum, the major portion of the albumen is precipitated when heat is applied, without first removing the casein. Sugar.—Milk-sugar occurs in milk to the extent of about 5%. It varies very little in quantity, seldom falling below 33% and seldom rising above 54%. It occurs in solution, and is found in no other place in nature. Milk-sugar is the most unstable component of milk. It COMPOSITION OF MILK. 17 quickly and easily decomposes. This decomposition is caused by micro-organisms. If these could be entirely excluded from the milk, it would keep for an almost indefinite length of time. As it is impossible under practicable conditions to entirely exclude organisms from the milk, the only way in which the growth of germs can be retarded: and prevented, and thereby prevent the changing of the sugar into other products, is to cool the milk to a low temperature (50° F.), or to heat the milk to a sufficiently high temperature (180° F.) to destroy most of the germs. According to Van Slyke and Hart, the decomposition of the caseous matter produces free casein. When about .5% acid has developed in the milk, the free casein combines with the acid and forms casein lactate. The chemical composition of milk-sugar is C12H2201; +H20. When a perfect decomposition of milk-sugar into lactic acid takes place, the following equation would represent the change: (Milk-sugar) (Lactic acid) Ci2HesO12 a 4C3H,603. Such an ideal change, however, never takes place. In such a case, one gram of milk-sugar should produce one gram of lactic acid. In a number of experiments carried on by one of the authors of “ The Analysis of Cream During Different Ripening Stages,” * the highest amount of acid produced from one gram of milk-sugar was .8 of a gram. This indicates that there are always accompanying by-products produced, besides lactic acid, when milk-sugar is being decom- posed in cream or milk. The sourness of milk is due to this change. The by-products which accompany the production of lactic acid are many and various. The most important ones are gases of different kinds, such as carbonic acid gas (COz); marsh gas (CH4); hydrogen (H); and nitrogen (N). A * Thesis I. S. C., Ames, Ia, 18 BUTTER-MAKING. small amount of alcohol, formic, acetic, and succinic acids are said to be normal accompanying by-products also. These by-products may also partially result from the breaking down of some of the other milk components. As milk-sugar is in perfect solution, it follows the water of milk, and in cheese-making nearly all of it passes into the whey. Commercially and chemically it is prepared from whey. It is a white, not very sweet powder, and is used for medicinal purposes to dilute pure, powerful drugs. It is also used extensively in the preparation of modified milk. Ash.—The ash of milk is present in very small quantities, and when viewed from such a standpoint it may first seem to be of small importance. On account of the effect of the mineral constituents upon the properties of milk, it is one of the most important components of the milk. It consists partly in solution, and partly in suspension. Babcock main- tains that about one-third of the usual ash constituents is in suspension, and that they consist chiefly of lime phosphate. All of the minerals in milk consist chiefly of potash, lime, soda, magnesia, and iron, combined with phosphoric, hydro- chloric, sulphuric, and carbonic acid. Calcium phosphate constitutes about one-half of all the ash constituents. They are named above, in order, according to the extent in which they occur in milk. Gases of Milk.—These do not normally exist in milk to such an extent as to enable chemists to determine them quan- titatively, but they are of great importance, owing to the effect they have upon the quality of the milk, viewing it in the commercial sense. Gases in milk may be divided into two classes according to their origin; namely, (1) those imparted to milk before milk- ing and (2) those which are formed and absorbed in milk later. (1) When freshly drawn milk has a characteristic cowy smell, which seems to be normal to all fresh milk. These gases are very volatile, and by cooling and aerating milk (differ- COMPOSITION OF MILK. 19 ent processes of which are now in use in this country) these gases can, to a large extent, be eliminated. The amount and kind of taints existing in milk, immediately after it has been drawn, largely depend upon the food which the cow has been fed. Turnips, onions, and garlic, when fed to cows a short time before milking, cause undesirable gases or taints to exist in the milk. Good sweet hay, bran, and good grass are said to produce milk of superior quality, and containing no bad taints, except the cowy or animal taste, which is natural to all milk when first drawn. The milk yielded by cows pasturing in the Alps of Switzer- land is said by tourists to possess a peculiar, not undesirable, spicy odor and flavor. It is maintained by the native people in Switzerland that the peculiar flavor of the Emmanthaler cheese cannot be developed anywhere else in the world. This flavor they believe to be due to the kind of vegetation the cows feed upon in the Alpine pastures. In Denmark, the poor people who do not own much land, graze their cows along the roads where weeds of different kinds grow. Milk from such cows has a peculiar characteristic odor or taint. In this country it is a common occurrence to find that milk delivered by patrons who keep their cows on timber-land pastures has a peculiar weedy odor. Especially is this true in the fall or late summer. These flavors are somewhat difficult to remove by the ordinary process of aeration. By heating such milk to 160° or 180° F., and stirring occasionally, most of these taints pass off. An addition of a small amount of saltpeter also improves it. Too much emphasis cannot be placed upon the food that the cows receive. While it is true that much of the desirable aroma and flavor in butter are due to bacterial growth, the kind of food fed to cows is not without significance. It is a well known fact that districts such as Normandy and Denmark, which have become famous for their high quality of dairy products, have the best of pasture and winter feeds. 20 BUTTER-MAKING. Besides the kind of food, some physiological disturbances of the cow may cause abnormal taints in milk. (2) Gases or taints which are formed in the milk or absorbed by the milk are due to fermentation and absorption respectively. The fermentation cause will be considered in a separate chapter, and the latter cause needs little explanation. It is a well known fact that milk, or any of its products, has the special property of absorbing odors which may be present in the surroundings of milk. For this reason, milk, as well as other dairy products, should at all times be kept in clean utensils and pure surround- ings. Abnormai taints appearing in milk immediately after milking are due to absorption within the cow. Taints that develop on standing are due to bacterial growth in the milk, or to absorption from impure surroundings. In removing undesirable taints from milk the first step is to remove the inciting cause, and the second to cause as many of these taints as possible to escape by a process of aeration or pasteurization. Coloring-matter.—It is not known of what the coloring- matter in milk consists. A substance named lactochrome has been found in milk. So far as known, this coloring-sub- stance is closely associated with the fat called palmitin. The amount of coloring-matter varies during the different seasons of the year. It also varies according to the different breeds. During the spring of the year, when cows are first put on grass, the color of the butter-fat is always higher than it is during the latter portion of the summer. During the winter, the fat in milk is quite pale. By feeding the cows some succulent feed in the winter, such as silage, carrots, and beets, the color of the butter-fat becomes much higher. From this it would seem that the change in the color of the fat with the different seasons, and the food fed, is closely associated with chlorophyl, the coloring-matter of grass. Other Constituents of Milk.—It is said that constituents such as citric acid, urea, nuclein, lecithin, and galactase are present. Babcock maintains that he has discovered a sub- COMPOSITION OF MILK 21 stance named fibrin. This seems to be similar to the nuclein mentioned by Fleischmann, if not the same. But as these substances are present to a very small extent, citric acid, urea, and fibrin being present to the extent of .12, .007, and .0002% respectively (Fleischmann and Babcock), they are of little importance. CHAPTER II. MILK SECRETION. The Mammary Gland as a Secretory Organ.— The mam- mary gland of females belonging to the order of mammalia, secretes a fluid known as milk. This substance is strictly a secretory product. There are two kinds of glands present in the animal body; viz., the excretory and the secretory. Gen- erally speaking, an excretory gland is one which receives or absorbs the waste matter of the body, and causes it to be carried off without causing any marked change to take place in the substance excreted. A secretory gland is one in which the raw material is obtained from the blood and then manu- factured into a special different product within the gland itself. As an example of a secretory gland, the milk-gland of the cow’s udder is an apt illustration. The glands in the mouth secreting saliva, and those in the walls of the stomach secreting the digestive fluids, are also secretory glands. Internal Structure of Cow’s Udder. — The cow’s udder is composed of two separate glands, the right and left halves. These two glands are distinctly separated from each other by a fibrous tissue running longitudinally. This fibrous par- tition extends along the abdomen in front, and back to a point between the thighs of the cow. It also serves to hold the -cow’s udder in place. ‘There is no connection at all between the right and left gland, and consequently milk cannot be ‘drawn from the left side over to the right, and vice versa. Each of these right and left halves is again divided into two parts, thus making the cow’s udder appear in quarters. The cow’s udder may then be said to consist of two glands 22 MILK SECRETION. 23 on the right side, and two on the left side. The divisions between the two glands on the side are not entirely complete. That is, there is enough connection between the two glands on the same side to allow a portion of the milk to be drawn from the rear teat to the front teat on the same side, and from Fic. 2—Schematic figure showing cross-section of cow’s udder; and also enlargement of epithelial cells in alveoli when cow is giving milk (1). Each alveolus is surrounded with a membrane called tunica propria. Cell nuclei not shown. When cow is in milk they are also enlarged. When not the epithelial!cells are flat and the nuclei small and spindle shaped (2). the front teat to the rear teat. The milk-glands proper are located near the abdomen and extend downwards into the udder a trifle. The remainder of the udder is filled with ducts, fibrous and connective tissue, muscle, nerves, and blood-vessels, the whole udder assuming a sort of spongy and open condition. 24 BUTTER-MAKING. The teat is simply a cylindrical-shaped body, with a hollow tube extending down through the center of it. At the bot- tom of this opening, or at the end of the teat, there is a sphincter muscle. This muscle in some circumstances is drawn up very tight, while in other instances it is so loose that it will not guard the milk from escaping. In case the muscle is so tight that the milk can be drawn only with difficulty, it may be relaxed a trifle by entering a small, smooth wooden plug. This will usually dilate the opening sufficiently, so that the milk may be drawn with comparative ease. In some instances this muscle is so tight that it is necessary to relax it by the use of a sharp knife. This, however, should be done with sur- gical skill; otherwise the whole muscle is likely to be so injured as to cause the milk to leak away at all times. The upper part of this canal in the teat connects with what is called the milk-reservoir. The size of this reservoir varies in different cows. The average capacity of this milk- cistern is about one pint. The opening from this reservoir into the teat is also guarded with a muscle. Over this muscle the cow has little control. Over the muscle at the lower end of the teat the cow has no control whatever. Opening into the sides and top of this reservoir is a large number of tubes, which are called milk-ducts. These milk- ducts extend from the reservoir up into the milk-gland. They radiate in all directions, divide and subdivide, so as to form a very large number of small tubes. These milk-ducts are surrounded with fibrous muscular tissue, nerves, and blood- vessels. They are all guarded by a special muscle at the junction to the main milk-ducts, from which they radiate. These muscles are so intimately connected with the nerves and muscular system of the cow that she is able to open and close them at will. There are very few cows that are not able to hold up their milk during nervous and exciting periods. It is a common occurrence for a milker to get only a small part of the milk from a cow. This small amount is the portion which is present in the teat and milk-reservoir. Some cows MILK SECRETION. 25 are able to hold up this milk also, but the majority of cows cannot perfectly control the muscle which guards the en- trance to the teat. The milk which is present in the milk- ducts and which has to pass through these junctions referred to above, can be held up by most cows at will. All of these small milk-ducts end in small sack-like bodies. Each of these dilated portions is called the gland-lobule or ultimate follicle. These gland-lobules enclose numerous individual microscopical bodies called alveoli or acini. These alveoli constitute the organs which possess the proper secre- tory functions. These alveoli are lined on the outside with a membrane called the tunica propria. Next to this membrane is a layer of cell-tissue. The inside layer is composed of cells, which are named the epithelial cells. These epithelial cells within the alveoli are supplied with blood from the cow’s system. During lactation they assume a different form. When the cow is yielding milk abundantly, these cells swell and extend into the cavity of the alveoli. When the cow is not in milk these alveolian cells become flat. A certain number of alveoli is tributary to one particular duct leading from the gland-lobule into still larger milk-ducts. Each aggregation of gland-lobules, tributary to one milk- cistern, constitutes a lobe, and may be likened to a side branch of a bunch of grapes. Each separate grape may represent a gland-lobule. The seeds within the grape, if we imagine each seed to be hollowed out and lined with small column-like bodies, may be likened to the alveoli. These column-like bodies would then represent the epithelial cells. The stem leading from each individual grape may represent the small duct which carries the milk on to the larger ducts. The main stems of the bunch may represent the larger ducts that enter into the milk-reservoir. The air which everywhere fills the openings or interstices of the various parts of the bunch of grapes may be likened to the fibrous fatty tissue between the alveoli and the lobules of the gland. Theories of Milk Secretion.—Although the theories of milk 26 BUTTER-MAKING. secretion have been studied considerably, many things in this connection are not well understood. Previous to the year 1840 it was thought that the only function of the milk-gland was to filter the milk as it transuded from the blood. It was supposed that the quality and quantity of milk depended entirely upon the food. The theory has also been advanced that the major portion of the milk constituents was a decom- position of the product of the lymph bodies of the blood. It was believed that the lymph bodies were a source of nourish- ment to the foetus, and that the calf received its nourishment from the same source after it was born as it did previous to birth. It was supposed that after the birth of the calf the opening on the uterus through which the food was supplied was closed, and that a new opening was formed in the milk- gland. These two theories have now been practically over- thrown. It has been demonstrated that the major portion of the milk is formed within the milk-gland. The fat, casein, milk-sugar, and part of the albumen are supposed to be formed in the udder. This conclusion is substantiated by the fact that these substances do not appear in the blood, at least not to such an extent as to warrant the assumption that they are not manufactured in the cow’s udder. The total amount of fat in the blood of the cow would not equal the fat in the milk from one milking. By some it is maintained that the substances in milk which are found in solution may be transuded directly from the blood. Here again milk-sugar is found to be in perfect solu- tion in the milk, but this substance can be found nowhere in nature besides in milk. It is not present in the blood of the animal, consequently it must be manufactured within the gland itself. The water of milk, and the ash constituents which are in solution, are probably transuded directly from the blood. No attempts have been made to determine definitely how casein and albumen are formed within the gland. The theory advanced for the formation of fat is, that the epithelial cells break down and form fat. When the breaking- MILK SECRETION 27 down process is completed, the transformed cells appear at the opening of the alveoli in the form of distinct fat-globules. This is supposed to be the origin and formation of fat-globules in milk; so it may be said that so far as known the fat is the result of a breaking down of degenerated epithelial cells. Dr. Bitting asserts that the formation of milk solids in the cow’s udder is probably due to a metabolic process rather than a a Fie. 3.—A schematic figure showing the course of the artery leading to the mammary g:and and the veins returning to the heart. The light-colored lines represent arteries and the dark-colored lines the veins. (From Bitting, Twelfth An. Report, Indiana.) to a degenerative. Collier found that a cow giving a normal amount of milk would secrete about 136,000,000 fat-globules per second. He also suggests that a cow secretes about 5 pounds of milk solids per day. As a cow’s udder weighs only about 24 pounds, the whole udder would have to be renewed twice daily. This is not consistent with our present knowledge of tissue building. 28 BUTTER-MAKING. The chief incentive to milk secretion is maternity. As soon as the young mammalia is born the blood which went to the uterus to supply the calf is turned towards the udder instead. As soon as this current of blood begins to flow, all of the blood- vessels and capillaries in the cow’s udder swell. This causes the minute blood-vessels or capillaries which form a network in the walls of the alveoli to swell. This swelling stimulates the epithelial cells to activity. Conditions Affecting Secretion of Milk.— There are a great many conditions which affect the milking capacity of a cow. These conditions may be conveniently grouped into two classes according to their causes: (1) conditions which are con- troiled largely by man, and (2) conditions which are inherent to the cow. 1. Some of the chief conditions which reduce the secretion of milk and are largely controlled by man are: improper care and treatment of the cow, lack of proper food, incomplete and improper milking, irregularity, and long periods between milkings. Pregnancy, nervousness, or excitement of any kind affect the proper working of the milk-glands considerably. These latter causes, however, are not always controlled by man. 2. Without denying the influence of those conditions men- tioned above, the conditions which chiefly affect the milk- secreting capacity are inherent. It does not matter how much good care and food a cow receives, if she does not possess these inherent necessary qualities. As was mentioned before, the milk-secreting capacity depends upon the number of gland- lobules, upon the amount of blood which is supplied to these secre- tory parts, and upon the capacity of the cow to digest and assimilate jood. ‘The number of gland-lobules is believed to increase until the cow is about seven years old. The milk-secreting glands are present only in a rudimentary form, until the cow has had her first calf, or is well advanced in the first stage of pregnancy. The gland-lobules then increase in number up to the age of about seven. The relative number of lobules in the cow’s MILK SECRETION. 29 udder can only be approximately ascertained. The size of the udder in some measure indicates this. A cow with a large flexible udder is usually a good milker, due to the fact that a large udder usually contains a large number of gland-lobules. The amount of blood which is turned through the cow’s udder to supply the milk-secreting cells may approximately be ascertained by the size of the blood vessels. The blood enters the udder from the heart near the region of the hips. It then passes down through the udder, along the abdomen just beneath the skin, until it reaches about midway between the flank and the girth. At this place it penetrates the abdom- inal wall and enters the thorax. The placc at which the blood penetrates the abdominal wall may be felt with the finger. It is supposed that the size of this hole is in some measure indicative of the milk-producing capacity of the cow. This opening in the abdominal wall is called the milk-hole or milk- fountain. Large irregular veins are considered a much better indication of good milking properties than small straight veins. The formation of gland-lobules is entirely inherent in the cow. The only way that these may be increased is through selection and breeding. The amount of blood which passes through the cow’s udder is also largely inherent, although this may in a small measure be affected by the amount and quality of food given to the cow. It should at all times be remembered that a cow is not a mere receptacle into which so much food can be introduced, and so much milk drawn from the other end. After giving due credit for the influence of all other conditions, we must still recognize that the inherent conditions affecting the secretion of milk are the most important. External Appearance of the Udder.—A cow’s udder should be well and symmetrically formed. It should be square, wide, extend well along the abdomen of the cow, and back up between the thighs. When the udder is empty it should be soft and flexible. The teats should be medium large, should be placed well apart, and should point downwards. There should be little or no depression in the udder between 30 BUTTER-MAKING. the teats; that is, each quarter should not appear distinct and separate when viewed from the exterior. The cow’s udder should be covered with fine soft, downy hair. A light golden yellow is said to be indicative of a good quality of milk. A firm, fleshy udder is undesirable. In the first place, itis not indicative of good milking qualities, and, secondly, such an udder is predisposed to inflammatory diseases. Milk-fever.— This is a common disease in fresh cows. It is due to a congested. condition of the cow’s udder. The decomposition products of the colostrum milk in the udder are absorbed by the blood, and produce the characteristic symptoms of milk-fever. Dr. Peters, of the Nebraska Experi- ment Station, says that a good and simple remedy for a diseased udder is to pump it full of air. This can be accomplished with an ordinary bicycle pump. After some air has been pumped in, then the cow’s udder should be worked or massaged with the hand so as to cause the air to pass through the quarter. He claims that the udder can thus be restored to its normal condition very quickly, thereby preventing and even curing milk-fever. In case the udder is caked very badly, apply a hot poultice. Small five- or ten-pound bags filled with bran and kept hot is a good substance to use. A compress is also used. This consists simply of using a piece of heavy cloth. Put it on so that it lifts up the entire udder, and tie it over the back of the cow. Straw should be put underneath it on the back so that the cord does not injure the animal. CHAPTER III. PROPERTIES OF MILK. Color.—The color of normal milk ranges between bluish white and golden yellow, according to breeds, foods, and sea- sons of the year. The milk yielded by Jersey cows generally is more yellow, due chiefly to the larger amount of fat which it contains. Holstein cows yield milk of a whiter color. Focds such as grass and certain roots (mangles and carrots) have the power of giving to milk a higher color. As has been pre- viously mentioned, the coloring substance in milk has been named lactochrome, and so far as known is associated with the palmitin fat. Flavor.—Milk has a sweet flavor, and a faint odor. Fresh milk has a peculiar cowy taste and odor, which pass off when exposed to the air. The flavor is affected by foods and con- ditions of the cow, as mentioned under “‘ Abnormal Milk.” Opacity of Milk.—Milk is opaque, except when seen in very thin layers; then it is slightly transparent. The opacity of milk is due to the presence of the fat and nitrogenous mat- ter. When these substances are filtered away on a fine clay filter (the Chamberland), the filtrate which passes through is clear and transparent. It has been maintained that the fat in milk is the chief cause of its opacity, and that the per- centage of fat could be determined according to the degree of opacity and transparency of milk with an instrument named pioscope; but it was soon found out that the size of the fat-globules, as well as the number, had considerable influence upon the degree of opacity of milk. For that reason, this method of determining the amount of fat in milk was not 31 32 BUTTER-MAKING. reliable. The fat-globules themselves are said to be almost transparent, yet the color and opacity of milk is largely due to their presence. This characteristic may perhaps be explained by assuming that the fat-globules in milk deflect the light instead of allowing it to pass through them. The opacity of milk, after the fat has been removed, is due to the presence of nitrogeneous matter. After the fat has been removed from the milk, the milk still continues to be opaque. When the albuminoid matter has been removed and filtered off the filtrate becomes clear and transparent. Chemical Reaction of Milk.—Milk when fresh shows an amphoteric reaction, which means that it exhibits both an alkaline and an acid reaction when tested with litmus paper. It turns blue litmus paper red, and red litmus paper blue. This peculiar behavior of milk is said to be due to the caseous matter in the milk, which itself has an acid reaction, but the remainder of the serum has a slight alkaline reaction. By testing the reaction of fresh milk with a tenth normal alkali solution, and using phenolphthalein as an indicator, it will be found to give an acid reaction. After standing, milk soon becomes dis- tinctly acid, which is due to a change of the milk-sugar into acids, chiefly lactic acid, through the action of micro-organisms. Richmond maintains that the amphoteric reaction of milk has acquired a false importance, as he believes that the neu- trality, as measured by the action of litmus paper, is not chemi- cal neutrality. Specific Gravity of Milk.—By specific gravity of milk we mean the weight of the milk as compared to that of an equal volume of water at the same temperature. If a certain volume of water weighs 1000 pounds, an equal volume of milk at the same temperature and under the same conditions, will weigh about 1032 pounds. Reducing the figure to a basis of 1, as is always done, the comparison between the two equal volumes of water and milk will be 1 and 1.032. This latter figure represents the average specific gravity of normal milk. It can be readily seen that the correct specific gravity can PROPERTIES OF MILK. 33 only be obtained at one given temperature, for, as the tempera- ture of the substance becomes higher, the density of it grows less, and consequently the specific gravity will be less. The tempera- ture at which the lactometers are standardized is 60° F. The variations in the specific gravity of milk will also vary according to the relative variation in amounts of the different components of milk. If a sample of milk is rich in solids not fat, as, for instance, skimmed milk, the specific gravity will be high and usually between 1.033 and 1.037. If the sample of milk is rich in fat, as, for instance, in cream, the specific gravity will be less. By adding water to milk, the specific gravity of it is lessened. Owing to this fact it was first thought that adulteration of milk with water could be detected by testing its specific gravity, But this method was soon found to be erroneous, as it is possible to take cream away and add water in such a proportion as not to alter the specific gravity of the sample. A low specific gravity of milk may, however, cause the suspicion that the milk has been adulterated, and the test for water adulteration can be supplemented by testing it for fat. As has been mentioned before, the lactometer reading should be taken at 60° F. If the temperature of milk is above or below, corrections must be made. The amount of correction which will give approximate results is .1 of a degree added to the lactometer reading for every degree Fahrenheit of tempera- ture the milk is above 60° F., and also .1 of a degree subtracted from the lactometer reading for every degree of temperature the milk is below 60° F. The temperature of milk when tested for lactometer reading should never go any lower than 10° below 60°, nor any higher than 10° above 60°. This would leave the range of temperature between 50° and 70° F. In chemical laboratories, the specific gravity of milk is usually determined by the use of a picnometer. In practice there are three instruments in general use for determination of lactometer reading, or specific gravity, viz.: Quevenne lactometer, New York Board of Health lactometer 34 BUTTER-MAKING. and the ordinary hydrometer. one that is used chiefly in creameries. one of them is given in the accompanying diagram. It may be The Quevenne 1actometer is the The graduation of each 1.000 r) i = -— 1 = 1.00544 = a 204 = rH = = |-—4 t— a 204] t.o10t-4 = | = RB 444 = - +04] 4.01544 sot is4—4 = = 4 Bn e044 7 || - a a = = #.0207— rot 204-4 Zz 4 = a I = = sot 4 = = 7 #025744 a at = oot = = a = +—4 — -—~4 109 [J 1.03044 = sed = 1104 = = a = 9.03344 12047 iq a a a 404-4 = Ld S N cc “S$” Specific Gravity Scale. “ N"” New York State, “Q" Quevenne, Fic. 4—Comparative graduation of lactometer stems, seen from the figures that in order to change the Quevenne lactometer reading into specific gravity, all that is necessary is to add 1000 and divide the sum by 1000. In order to change the PROPERTIES OF MILK. 35 specific gravity into lactometer reading the reverse process will give correct results. The hydrometer gives the specific gravity directly. The Board of Health lactometer has a special graduation. In devising this lactometer it was thought that 1.029 was the minimum specific gravity of unadulterated milk. The scale on this lactometer was made from zero to 120; zero marking the point which represents the specific gravity of water, namely, 1. 100 is the point which is assumed to represent the least specific gravity of milk 1.029. If the specific gravity of a certain sample of milk fell to 90, it indicated that there was 10% of water present. If it fell to 80, it indicated that there was 20% of water, etc. In order to calculate the total solids, and solids not fat, of milk, it is necessary to know the lactometer reading, and the percentage of fat content. Knowing these factors, by the use of the following formula given by Farrington and Woll, and deduced from Fleischmann’s work, the total solids, and solids not fat, can be found: Solids not fat=} lact. reading + .2 times the fat. Total solids =fat+solids not fat. Natural Separation of Milk and Cream.—When milk is allowed to stand quietly for a short time, a layer having a rich- yellow color comes to the surface. This is the cream, and contains most of the fat. This separation is due chiefly to the difference in weight, or specific gravity, of the fat-globules and the serum. The force which acts upon the globule of fat is the difference in weight between the fat-globule and the serum which it displaces, minus the resistance force with which it meets in its upward passage. In milk with a high degree of viscosity this force is great. In milk of a limp and liquid consistency this force is smaller. By adding water the vis- cosity of milk is reduced considerably, ‘and the specific gravity of the serum is also decreased. But the effect of the added water upon the viscosity is greater than the effect the water has 36 BUTTER-MAKING. upon the specific gravity of the serum; hence, by adding water to milk, the resistant force is decreased to such an extent as to get a more rapid and more efficient separation of the fat. The water dilution separators are based upon this principle. In normal milk, the amount of fat left in the skimmed milk by natural creaming is about .4%. The fat which is left in this skimmed milk is largely composed of very small globules. This is due to the fact that the resistant force of these small globules is equal to cr greater than the buoyant force acting upon them. Fie. 5.—Standardized milk. Showing the amount of cream on milk con- taining the designated per cent of butter-fat. (From Bul. 92, Ill.) This completeness of natural skimming is to a certain extent based upon the mathematical law which is stated as follows: ‘‘The surfaces of two spheres are to each other as the squares of their diameters, and their cubical contents are to each other as the cubes of their diameters.” The larger the globules are, the greater the surface is, and the greater the resisting force to which they are subjected. From the law stated it can be seen that as the size of the globule increases, the cubical content increases more rapidly than the surface. If a fat-globule were split up into smaller ones, there would be more surface exposed PROPERTIES OF MILK. 37 to the serum than was the case while the fat was present in one globule. For illustration, take two globules of fat having a diameter of 4 and 2 inches respectively. ‘The squares would be 16 inches and 4 inches respectively; their cubes would be 64 inches and 8 inches respectively. It will thus be seen, according to the law quoted above, that the larger globule has a surface only four times as great as that of the smaller one; but the cubical content of the larger globule is eight times that of the smaller one. This illustrates why the large globules rise in cream quicker than the small ones. In this particular instance the upward force the larger globule is subjected to is eight times greater than that of the smaller one, while the resistance force is only four times as great as that of the small one. Adhesion of Milk.—Normal sweet milk adheres to wood, glass, and metals to a greater extent than does water. Whole milk has greater adhesive properties than skimmed milk. A paper moistened with milk or cream makes a label that will stick to any dry object; the same paper moistened with skimmed milk has less adhesive power. The adhesive prop- erties of milk are also due to the condition of the nitrogenous matter. This fact is made use of in painting and whitewashing. Slacked lime, when mixed with buttermilk, or milk of any kind, gives a whitewash which will remain on objects much longer than that made by mixing with water. Viscosity of Milk.—Milk is more viscous than water. The degree of viscosity of fresh milk varies chiefly with the tem- perature and fat content. So far as understood, the lower the temperature, the greater the viscosity. Development of acid, and high temperature lessens the viscosity of milk. Pas- teurized milk or cream is less viscous than the same milk or cream unpasteurized. This lack of body can again be restored by adding a little viscogen, as recommended by Babcock and Russell. It is advisable not to use it, however, as it does not add materially to the nutritive value of milk. It merely restores the body. 38 BUTTER-MAKING. The great viscosity of thick and cold cream has been encountered by most butter-makers when attempts have been made to churn cream under such conditions. It adheres to the inside of the churn and does not agitate. It simply rotates with the churn. Cream that is cold and _ thick whips more easily than thin and warm cream. The viscosity is so great that the air incorporated cannot escape so easily. In ice-cream making, a greater yield is obtained by using cold and thick cream. The air, when once incorporated, cannot easily escape, owing to the great viscosity of such cream. Specific Heat of Milk.—The specific heat of milk is less than that of water; that is, it requires less heat to warm a definite amount of milk to a certain temperature than it does to heat “the same quantity of water to the same temperature. It also takes less ice to cool the same volume of milk to a cer- tain temperature than it does to cool the same quantity of water to the same temperature. The specific heat of milk is, according to Fjord, .94. The specific heat of cream is about .7. It varies according to the percentage of fat in the cream. The specific heat of butter is about .4. From these figures it will be seen that it takes less heat to warm milk, cream, and butter, and less cold to cool the same substances, than it does to heat and cool water; but it takes a longer time to heat or to cool milk, cream, and butter; that is, the milk, cream, and butter are not as rapid conductors of heat and cold as is water. The maximum density of milk is not, like water, at 4° C. but at about .3°C. The boiling-point of milk is a trifle higher and the freezing-point a trifle lower than that of water. Effect of High Heating (180° and above) on Properties of Milk.—The chief effects of heat upon milk may be summarized in the following headings: (1) It destroys nearly all germs present in the milk. (2) It diminishes the viscosity, or body. (3) It drives off gases. PROPERTIES OF MILK 39 (4) It imparts a cooked taste (especially if not heated and cooled properly). (5) It precipitates some of the albuminoids and ash con- stituents. (6) It destroys the properties of enzymes present in milk. (7) It divides or splits up the fat globules. (8) It caramelizes some of the sugar. 1. Destroys Nearly All Germs.—Heating milk to a tem- perature of about 180° F. for ten minutes destroys most of the germs present in milk. This is the temperature used chiefly in creameries for pasteurization. The details concern- ing the different effects of temperature upon growth of germs properly comes under the heading of bacteriology, and will be referred to more in detail in the chapter on “ Bacteria in Milk.” 2. Diminishes the Viscosity, or Body.—Heating milk or cream diminishes the viscosity of these substances; that is, the body or consistency is lessened; and in cities where milk or cream is sold directly to consumers, heated milk appears as if it had been adulterated. This diminution in the body is claimed to be due to a breaking up of the fat-globules and the caseous matter. The chemical union of some of the cal- cium salts and the casein is altered or destroyed. The consistency of milk or cream can be restored by adding a substance named viscogen. Russell and Babcock * advise this method of overcoming the apparent defect caused by heating. It consists of making a strong solution of cane-sugar and mixing it with freshly slacked lime. This mixture is allowed to stand, and the clear solution coming to the top is the viscogen, which, when drawn off and used in the pro- portion of one part of viscogen to from 100 to 150 parts of cream, restores the body of cream or milk. This is due to the fact that viscogen causes the fat-globules to cluster together again, and the lime in the viscogen may combine with the * Bulletin No. 54, Wisconsin 40 BUTTER-MA KING. nitrogenous constituents in such a way as to aid in the resto- ration of the body of the cream or milk. Nearly all dairy laws forbid the addition of any foreign substances to milk or cream. If viscogen is added, Babcock and Russell suggest to name it. visco-milk, visco-cream, etc. When this modification is made, then no objection can be raised to its legitimate use. Fic. 6.—Microscopic appearance of milk, showing natural grouping of the Naas Single group in circle, highly magnified. (From Bul. 64, 3. Drives off Gases.—When milk is heated, taints, and gases of different kinds pass off to some extent. This is facili- tated by heating and stirring in an open vessel. Many of these gases also escape when milk is aerated and cooled in a pure atmosphere. 4. Imparts a Cooked Taste.—When milk is heated to 160° F. or above, it assumes a distinctly cooked taste, which makes it disagreeable as a food for many people. On this account, milk for city supply in America is generally not heated. In a few cities where milk is consumed directly, heating and cooling (pasteurization) has been generally introduced. It is said that people can become accustomed to this cooked flavor and acquire a liking for it. When milk is not heated higher than 180° F., nor exposed to the heat very long, and PROPERTIES OF MILK. 41 cooled quickly, the cooked taste can be greatly reduced and almost entirely avoided. Where heating or pasteurization of cream has been adopted, as in some creameries, the pre- vention of this cooked flavor in the butter is of vital importance. The reason why this cooked flavor forms in milk when heated is not well understood. It is supposed to be due to the effect which heat has upon the nitrogeneous constituents of milk. 5. Precipitates Albuminoid and Ash Constituents.—When milk is heated, there is a tendency for the soluble salts and a portion of the albuminoids to be thrown down, or changed into an insoluble form. The higher the milk is heated, the greater is this tendency. By subjecting a sample of milk in a flask to intense heat, and then allowing it to stand, a fine white sediment will be deposited on the bottom. This is believed to be minerals precipitated from the milk. When milk has been heated to about 170° F., and cooled, rennet is unable to precipitate the curd in anormal way. The curd resulting from adding rennet to pasteurized milk is floccu- lent in nature. It does not assume that smooth and even texture that curd from raw milk has when precipitated with rennet. This abnormal behavior of pasteurized milk towards rennet can be reestablished by adding a small quantity of calcium chloride (CaCl). Whether this would effect the quality of cheese materiaily has not yet been determined definitely. According to G. Fascetti,* if pasteurized milk is used for cheese-making, the cheese ripens more slowly than when made from raw milk. The same investigator also claims that a larger quantity of cheese is obtained per 100 parts of milk when pasteurized milk is used. 6. Destroys Properties of Enzymes.—As was mentioned in the composition of milk there is a substance normal to milk named galactase. This is an enzyme. By heating milk to * Exper. Sta. Record, Vol. 15, No. 10, 1904. 42 BUTTER-MAKING. about 175° F. the properties of the enzyme are destroyed Owing to this it is easy to detect whether a certain sample of milk has been pasteurized or not. Galactase is present in sosmall a quantity that it could not be determined in milk quantitatively. It must be detected in a qualitative way. The test used and invented by Storch, of Copenhagen, Denmark, is to put a small quantity of milk in a test-tube, add to it a small quantity of a weak solution (2%) of hydrogen peroxide (H202), a small quantity of potassium iodide, and a little starch solution. The whole mixture is then shaken. If the mixture does not change in color, it has been heated to at least 170° F. If it turns blue, it has not been heated to a sufficiently high tempera- ture to destroy the properties of the enzyme present in the milk. Another test which can be used in distinguishing raw milk from scalded or boiled milk is to take 10 cubic centimeters of the milk to be tested, add 1% of recently prepared aqueous solution of “Ortol,’’ and then one or two drops of hydrogen peroxide. If the milk has not been heated, a vivid red color is produced. Heated milk shows no effect. 7. Divides the Fat-globules.— The fat-globules in normal milk are grouped in minute clusters. When milk is heated, these clusters break up, and each globule exists more or less independently. When heated to an excessively high temperature, and exposed to this temperature very long, the fat-globules tend to run together. This can be proved by heating milk in an open vat for about half an hour. A small amount of yellow fat will then be seen floating on the top. 8. Caramelizes the Sugar.—The brownish color which the milk assumes when it is heated excessively is due to a change which the milk-sugar undergoes. Fleischmann claims that the sugar begins to change into a substance known as lacto-caramel at a temperature of 160° F. This change, however, is not pronounced enough to be apparent in the color, unless the milk is heated a long time. The higher the temperature is, and the longer it is exposed to the heat, the more pronounced is the change. PROPERTIES OF MILK. 43 General Remarks.—While all of the above changes have been found by investigators to take place when milk is heated, they can, in a measure, be avoided, if special precautions are taken in the heating and cooling of milk with the special, recently improved forms of apparatus for heating and cooling milk. The heating to 160° F. can be accomplished without changing materially the chemical or physical properties of milk.* Rapid heating and rapid cooling seem to be two essen- tials in order to prevent changes from occurring in the milk. * Fjadon, Koshe, and Hertel in Exp, St. Record, Vol. 14, No. 5. CHAPTER IV. FERMENTS IN MILK. Definition.—The changes which milk undergoes by standing at a suitable temperature are called fermentations. The causal agents are called ferments. There are two kinds of ferments in milk; viz.: (1) the organized, and (2) the unorgan- ized. The latter includes the enzymes. So far as known, only one pre-existing enzyme is found in milk. This one was dis- covered by Russell and Babcock. They named it galactase. It is a tryptic ferment. This galactase is present to such a small extent in milk that it exercises very little influence upon the characteristics of milk. If the milk were rendered entirely sterile or free from organized ferments, the fermentative changes would proceed at an unusually slow rate. The galactase has been suggested to be of some importance to the butter-making industry. The properties of galactase, like those of any other enzyme, are destroyed by heating to or above a temperature of about 175° F. The organized ferments are by far the most important to the dairy industry. It should be understood in this connection that the organized ferments may produce unorganized ferments, or enzymes, as products, but these produced enzymes do not exist in milk, like galactase, when it is first drawn from the cow. The organized ferments of milk consist chiefly of bacteria. There are present also some yeasts and molds. It is a common impression that bacteria are animals, which is incorrect. Bacteria are minute microscopical plants, belong- ing to the lowest order of plants in the vegetable kingdom. Bacteria differ from the ordinary plants that we see, in that they are composed of a single cell containing protoplasm, 44 FERMENTS IN MILK. 45 while the plants that we see in every-day life are aggregations of cells. Some bacteria are motile, while others are not. Size and Shape of Bacteria.—In size, bacteria are the smallest organisms that exist, so far as known. The size varies con- siderably. Russell * gives the average diameter as xp455 of an inch. They are so inconceivably small and light that nine hundred billions of them would only weigh =‘; of an ounce. t Bacteria also vary considerably in shape. They are as a rule classed into three groups: (1) The bacillus or rod-shaped; (2) The coccus or ball-shaped; (8) The spirillum or spiral- shaped (like a corkscrew). Some types of bacteria are clas- sified according to the way in which they adhere to each other. For instance, when two cocci occur together and form a pair, they are called diplococci, when bacteria occur in chains, they are called streptococci, when bacteria appear in bunches they are called staphylococci, etc. FavorABLE CoNDITIONS FOR BacrertaL GROWTH. Food.—Bacteria are like other plants in nature,—they need food for their existence. However, they require their food in solution. Nitrogen, carbon, oxygen, and mineral matter are essentials for bacteria. These substances are furnished in abundance in milk from casein, albumen, milk-sugar, and the mineral salts. Butter-fat in milk is said to be of little value as a food for bacteria. Some bacteria prefer a substance having an acid reaction in which to grow; others thrive best in an alkaline medium. Most bacteria, however, prefer a neutral or slightly alkaline substance. Darkness is essential to some bacteria, and is preferred by the majority of the different species. Bright sunlight is a very effective germicide. It is fatal to all species, so far as known. Some germs require air for their growth. These are called aerobic. Others again grow only in the * Dairy Bacteriology. ft Milk, Its Nature and Composition, by Aikman. 46 BUTTER-MAKING. absence of air. These are called anaerobic. Some grow under either or both conditions, and are called facultative aerobic or facultative anaerobic. Temperature.—Favorable temperature is essential to bac- terial growth. Temperature is, indeed, the most important means by which the growth and development of bacteria can be controlled. The range of temperature at which bacterial growth can occur may be placed between freezing-point and ah tats ee LS SAIN ay t wf N vee We 0 GOA NS es rv Stee sy ' aS t ‘ ~ vt vy TS i tae a i \ Ses as “he Pup yh Vy Wy rn) De Ud TEs bee Fic. 7—a, single bacterium; b, progeny resulting from the growth of a bac- terium during 24 hours in milk at 50° F.; c, progeny of a bacterium during 24 hours growth in milk at 70° F. At 50° F. multiplication was 5-fold. At 70° F. the multiplication was 750-fold. (Bul. 26, Storrs, Conn.) a little above 110° F. The growth of bacteria at these ex- treme temperatures is very slight. Even at 50° F. the rate of growth is very slow. According to experiments conducted by Dr. Conn, the multiplication of bacteria at 50° F. was 5- fold. while at 70° F. the multiplication was 750-fold. The following table shows the number of bacteria per cubic centi- meter in milk kept at different temperatures: * In 50 H No. of No. Bost | Bap | Hae | Hep | eu | eeebs.| metab set. o o o ‘urdli; 0! - 3] is Bt OOS abs 0". at BO". at 70°" Hite at 50° ling at 70°, 46,000 | 39,000 | 249,500 |1,500,000 5 12,000,000 190 56 47,000 | 44,800 | 360,000 | 127,500 | 792,000,000 289 36 36 hours 50,000 | 35,000 | 800,000 | 160,000 | 2,560,000,000 172 42 42 hours * Bull. 26 Storr’s Stn., Conn. FERMENTS IN MILK. 47 All bacteria do not have the same optimum growing tem- perature. Some species develop most rapidly at one tempera- ture, while other species prefer a different temperature for the greatest development. It is on this account that certain tem- peratures are employed in ripening of starters and cream. According to researches by Conn, Bacillus lactis aerogenes develops very rapidly in milk at 95° F. It produces much gas and an unpleasant flavor in the milk. This particular species sours milk very rapidly. As a rule, milk which has been held at this high temperature, contains a preponderance of this undesirable species of bacteria. At 77° F. results are more uncertain. The species of bacteria which will predominate in milk at this temperature depends in large measure upon the number of each kind present. According to Conn, Bacillus lactis acidi has the highest relative growth at about 70° F. This particular species produces no gas, and is desirable to have present in cream for butter-making. Milk kept at this tem- perature will, in most cases, providing it has previously been properly treated, develop a pleasant acid taste, will curdle into a smooth uniform coagulum, and will contain a preponderance of the species of germ mentioned above. At as low a temperature as 50° F. acid-producing types of bacteria do not develop very well. But Conn maintains that at this temperature miscellaneous species of bacteria develop that produce unfavorable results. While milk does not easily sour at this temperature, it should be remembered that un- desirable germs are constantly developing. As it is practically impossible to exclude: all of the bacteria from milk during milking and the handling of the milk, it is very essential that the multiplication of the germs present be checked, or at least retarded; and this can be done by controlling the temperature of the milk. As low temperature is effective in checking the multiplication of the bacteria, the sooner the milk can be cooled after it is drawn, the better itis for the keeping quality of the milk. Moisture.—Moisture is one of the essentials for bacterial 48 BUTTER-MAKING. growth. As milk is composed largely of water, bacteria find in milk a good medium for growth. All the other required food elements are also found in abundance in milk. Damp utensils and rooms are always more conducive to the growth of germs than are utensils and rooms which are thoroughly dried and ventilated. This is well illustrated by a refrigerator. A very damp dark refrigerator is always more conducive to the growth of molds in butter than is a dry refrigerator. Unfavorable Conditions for Bacterial Growth.—The reverse of the favorable conditions mentioned above would be un- favorable to the growth of bacteria. As it is practically im- possible to make conditions unfavorable for the growth of bacteria by taking away food, other means must be used. Extremely high temperatures destroy bacteria. Low tem- peratures check their growth, but so far as known do not destroy them. Absence of moisture and presence of direct sunlight are conditions which are not conducive to bacterial growth. Certain chemical substances when added to milk, or to the medium in which the bacteria are present, are very un- favorable to their growth. Some of these chemicals entirely destroy all germ life when added in even very small quantities. These are called disinfectants (formaldehyde, corrosive subli- mate, etc.). Other chemicals are more mild in their effect upon germ growth, and merely inhibit or retard the growth of micro- organisms. The chemicals which have this milder effect upon germs are called antiseptics. Boracie and salicylic acids are examples. Practically all disinfectants are violent poisons, and should not be used in any quantity or in any form in milk or dairy products which are intended for human food. The milder preservatives, or the antiseptics, are, as a rule, not so poisonous or injurious to human health. In some countries they are allowed to a small extent. For instance, according to reports, the laws of England permit the use of boracic acid to the extent of 0.5 of one per cent. It is, however, safest not to use any of these chemicals, except for preserving samples for analytical or similar purposes. As low and high temperatures FERMENTS IN MILK. 49 are so effective in producing unfavorable conditions, these should be chiefly employed in controlling the growth of micro- organisms in the dairy industry. Kind of Germs Found in Milk.—The number of species of germs found in milk has not. yet been definitely established, due chiefly to the fact that it is in some instances difficult Fic. 8—Shows a plate exposed in pasture where air must have been very pure and free from germs, (Bul. 87, Nebraska.) for bacteriologists to differentiate one species from another. The description of one species of bacteria by two different bac- teriologists may vary considerably, as the characteristics of the germs depend so much upon the conditions throughout the classification process. Over 200 different species have been described. It is possible, however, though all of these types may have different morphological and physiological characteristics as described by different bacteriologists, that some two or more of the 200 types may belong to one species. 50 BUTTER-MAKING. For this purpose, it is sufficient to classify the bacteria into three groups; viz., (1) those which are harmful to the butter- making industry, (2) those which are beneficial, and (3) those which are indifferent, or produce neither good nor bad results. From the farmer’s or milk-producer’s standpoint, none of these bacteria are desirable. Each milk-producer should Fic. 9.—Shows a plate exposed one-half minute under a cow’s udder treated with a 5% solution of carbolic acid. (Bul. 87, Nebraska.) make it a point to prevent their entrance and suppress their development in milk and cream to as great an extent as pos- sible. The creamery operator should endeavor to suppress all of the harmful germs, and foster the development of the desirable ones. The germs which are desirable belong chiefly to the acid- producing types. They are often called lactic ferments. The harmful bacteria include those which produce bitter milk, red milk, blue milk, yellow milk, slimy milk, etc. There FERMENTS IN MILK. 51 is a number of species belonging to this group. The patho- genic germs, or disease-producing bacteria, must also be classed with the harmful bacteria. It is not the intention in this work to give an extended discussion of this subject. For such discussion see special works on Dairy Bacteriology. Fic. 10-—Shows plate exposed one-half minute under cow’s udder treated by merely brushing with the hand; each little spot represents a colony of some kind of bacteria. (Bul. 87, Nebraska.) Number of Bacteria in Milk.—The number of bacteria found in milk varies so much that it is practically impossible to state accurately the average number. The number of germs found varies according to several conditions, such as degree of cleanliness of cows, utensils, and milker; degree of purity of the atmosphere when the cows are milked; and the temperature at which the milk is kept. When the milk is being produced under the best practical sanitary conditions, the number of germs need not exceed 10,000 per c.c. Such 52 BUTTER-MAKING. results cannot be obtained unless extreme precautions are taken. Milk produced under average farm conditions sel- dom contains less than 50,000 germs per c.c. shortly after the milking. Milk which is produced under filthy conditions, and which is several hours old, may contain several millions of bacteria per c.c. Sources of Bacteria in Milk.—Except in the cow’s udder where they are present to only a small extent, bacteria are present almost everywhere. They float in the atmosphere i TS Fic. 11—The wrong and the right kind of a milk-pail. a, the ordinary type of pail showing sharp angle between sides and bottom; B, the same peepery flushed with solder so as to facilitate thorough cleaning. The ower figure represents a joint as ordinarily made in tinware. The de- pression a affords a place of refuge for bacteria from which they are not readily dislodged. This open joint should be filled completely with solder. (From Bul. 62, Wis.) and adhere to particles of dust. Especially is this so in the dusty cow-stable. They are present in all well water to a greater or less extent. They are very abundant in streams and rivers. They are present in the soil to a depth of several feet, the number decreasing with the depth. As these germs are prac- tically present everywhere, the source of germs in milk may be said to be all around us. The principal sources of germs in milk are, however, unclean dairy utensils, unclean cows, and unclean surroundings. As these germs multiply chiefly by fission, or by one cell dividing into two, it is plain that the number of germs will increase very rapidly under favorable conditions. Under the most favorable conditions it requires FERMENTS IN MILK. 53 approximately twenty minutes for this process of fission to take place. Some germs develop small bodies within the cell, called spores. It is not difficult to destroy the sporeless cell by heat, but the spores are very resistant to unfavorable con- ditions. The spore-bearing bacteria cannot be destroyed by boiling. The heating destroys the vegetative cell, but the spores still remain. In order to destroy the germ in the spore form, it is essential that the milk be cooled to a temperature favorable to growth, and then allow the spore to develop into a vegetative cell. If heat is again applied, the milk can be rendered entirely sterile. Usually three or four successive heatings and coolings are necessary in order to render the milk completely sterile. A single heating under pressure (15 minutes at 15 pounds) kills them at once. It has been demonstrated by several investigators that freshly drawn milk is not a good medium for bacteria to develop in. In fact, several experiments seem to indicate that milk acts as a germicide to certain varieties of bacteria. For instance, the cholera germ is to some extent destroyed in fresh milk, but it is not known to what extent. Organisms producing lactic acid check the multiplications of these pathogenic bac- teria. This germicidal property is said to be common, to a greater or less extent, to all the animal secretions. Effect of Thunder-storms on Souring of Milk.—It is a common impression that thunder-storms hasten the souring of milk. This was attributed to the electricity in the air accompanying the storm. Experiments by several investigators have proved that electricity does not have any effect on hastening the fer- mentative changes of milk. The reason why milk sours quicker when an electrical storm is approaching, is that the air tem- perature is usually higher then than at any other time. This higher temperature warms the milk and creates more favor- able conditions for the rapid multiplication of the germs present in the milk. It is for this reason that milk sours quicker during or previous to a thunder storm than at any other time. CHAPTER V. ABNORMAL MILK. Colostrum Milk.—Colostrum is the milk yielded immediately after calving. As the time of calving approaches, a cow usually diminishes in her milk-producing capacity. Most cows become dry about two months previous to parturition. If they do not naturally stop giving milk, they should be dried up so as to have a seven week’s rest before calving. When the rest has been given, the cows yield, immediately after calving, milk which has a composition and characteristics different from those of normal milk. If the cow continues to give a copious flow of milk up to the time of calving and is not allowed any rest, the difference in the milk yielded before calving and after calving is compara- tively slight. The composition of colostrum varies considerably during the first three days after calving. According to Engling, as reported by Richmond, the composition is a follows: WeAb eric dicta tien leew Gch Geared aries 71.69% Hatscacatuerrisssaivenwhine atau 3.37 ee ASEM Gps ave cetls deere eye 4.83 Albuminoids | amen le soe alee adetees 15.85 BUPA, veaqerea ae cos saweus sereeteowRe 2.48 Aelis b.tkchoeanercesiaren Grime eeal 1.78 Colostrum greatly changes in composition and appearance as it gradually assumes the characteristics of normal milk. It is at first reddish yellow in color, and has a viscous and slimy 54 ABNORMAL MILK. 55 consistency. It is a food which the newly born calf should not be deprived of, as it seems to be specially suited for the digestive tract of the young calf. It will be seen from the above table that the water content of colostrum is less than that of normal milk. The fat content is a ittle lower than that of normal milk. The most striking characteristics of colostrum, however, are the low content of sugar, and the large amount of albumen. Of the latter substance very little is present in normal milk. The mineral constituents of colostrum also run quite high. The specific gravity of colostrum varies from 1.046 and 1.079. When boiled, the nitrogenous matter coagulates. The colostrum is not considered to be suitable for food until about four days after parturition. Whenever it can be boiled without coagulating, it is claimed to be safe to use. At times a cow’s udder becomes inflamed after calving. In such cases the abnormal qualities of the cow’s milk will extend over a greater period of time than that mentioned above. Salty Milk—The average chemical analysis of salty milk as calculated from results obtained by the analysis of such milk from four cows given by Boggild,* is as follows: Waters girs 5 dhe ee deh Dea leweert ks 91.09 ati eeticeash® 2abe Gal, Gey Males a ede aece 124 2.09 Nitrogenous matter....... ...... 0... 2.90 US ieee he i , 6 a SEE Ct A aan we TR Rr Sa: Fic. 58.—The Ideal skim-milk weigher. draw a chalk line on the outside of the can some distance below the surface of the milk. This indicates the point to which the can may be filled with skimmed milk. CHAPTER VIII. COMPOSITE SAMPLES. Definition—In order to avoid testing each patron’s milk or cream every day for fat, a small sample, which represents the average quality and a proportionate part of the whole, is taken from each patron’s milk every day and placed in a jar. A preservative of some kind is previously added, which keeps it from spoiling. This is called a composite sample. When to Sample.—Some makers prefer to sample the milk or cream delivered every day; others prefer to sample every other day. Some creamery operators, again, sample four or five times in succession at intervals, the patrons being unaware of the time when the sampling is to take place. The most reliable and practical method, however, is to take a sample every day, and test it for fat at the end of every two weeks. When cream is received it is not reliable to take composite samples. Kind of Preservative to Add.—A number of different pre- servatives are now in use, and different ones are being recom- mended for creameries and cheese factories by various authori- ties. Even a few of the best authorities differ as to which one of the preservatives gives the best results. Among the most common of the milk preservatives, and less poisonous than certain others, are salicylic acid, borax, boracic acid, and bicarbonate of soda. Among the more vio- lent poisons and strong preservatives are formaldehyde and its compounds, chloroform, corrosive sublimate, and bichromate of potash. Bichromate of potash and corrosive sublimate are the two most commonly used in preserving composite samples. The former is recommended highly by Farrington & Woll on 99 100 BUTTER-MAKING. account of its relative harmlessness, its cheapness, and efficiency. While bichromate of potash is relatively efficient in its preservative effect, and not so poisonous as some of the others, it does not give as general satisfaction as does corrosive sub- limate (mercuric chloride), unless relatively greater precau- tions are taken. If the composite samples preserved with bichromate of potash are left standing in the light very long, a leathery scum forms on the top, which is very difficult to dissolve in the sulphuric acid. This is claimed to be due to the reducing influence of light on chromate solutions. If too Fic. 59.—Composite Fic. 60 —Composite samples and rack sample bottle. to hold sample jars. much bichromate of potash is added, the sulphuric acid added digests the curd with difficulty. When the sulphuric acid is added the curd is precipitated into a heavy, gray-colored coag- ulum, which dissolves with difficulty in the acid. According to the authors’ experience, corrosive sublimate tablets can be highly recommended. The tablets contain a color, which, when dissolved, colors milk, so that it can readily be distinguished as not being fit for human food. The tab- lets are very poisonous, but are more efficient in their preser- vative effect than bichromate of potash. They can be obtained from any creamery-supply house. During the winter, when the samples are kept comparatively cold, less preservative is needed than in the summer. One TOT (0,) Azatrvary pryUAUTJUO ‘ )) ‘sopjoq aydtuts jo quatSuvsie Suraoys ‘u001-Sulysay— 19 “DIY RUESRRIPELERLES 102 BUTTER-MAKING. corrosive sublimate tablet will keep a half-pint to a pint of milk or cream in good condition for about two weeks in summer, and about three weeks in winter, providing the sample is properly cared for. Some makers are practicing testing at the end of every month during the winter, and every two weeks during the summer. Testing at the end of every month saves labor, but it is not a reliable method to follow under all conditions, as some of the samples are likely to be somewhat impaired after standing so long. Arrangement of Composite Samples.—Pint glass jars with covers are, so far as known, the most convenient vessels to use for composite samples. Shelves should be arranged in the weighing-room on which to keep the bottles. If possible, it is best to have them in a case closed with glass sliding doors. This is neat, and, if the glass doors fit well, the samples are in some measure protected in case of quick, unexpected changes in temperature. These sliding doors should be locked when the creamery operator is absent from the creamery, in order to prevent any tampering with the composite samples. The best method of arranging the sample jars is to have all the jars belonging to the patrons of each route standing in one group, or on one shelf together, if possible. The bottles are numbered to correspond with the number given each patron on the milk sheet. The name of the hauler, or the number of the route, can be put on each shelf. The samples be- longing to those who haul their own milk can be put on another shelf. These can be designated as individual haulers. Such a classification, when the bottles are plainly numbered, will often prevent the mistakes that are likely to occur if the bottles are simply numbered and put into a rack together. Care of Composite Samples.—In the first place the jars should be kept scrupulously clean. It makes the test unreliable if the jars are left covered with milk and molds round the neck from one month to another. When the samples have been tested the jars should be thoroughly cleaned, and, if necessary, scalded, before they are used again. Care should be taken to COMPOSITE SAMPLES 103 spill as little milk as possible around the neck, inside as well as outside, of the bottle when the sample is put in. If the nulk is spilled there, it makes an unattractive appearance. Very often it becomes moldy, and, as more milk is added and the sample shaken every day, this mold gradually extends down the sides of the bottle. This causes the composite sample to be infested with undesirable growth, and to spoil sooner than oo Sea Fig. 62.—Testing-room in Model Dairy, St. Louis Exposition. (Chicago Dairy Produce.) it would if greater care were taken in keeping the milk from coming in contact with the sides of the bottle, before coming in contact with the preservative. It is important also that the sample jars be well covered, otherwise the moisture evaporates and causes the milk or cream to dry up. It also makes the test unreliable by increasing the per cent of butter-fat. A gentle rotary motion should be given each jar when a sample is added to it to mix the cream, which rises to some extent after the milk has stood a while. 104 BUTTER-MAKING. Average Sample.—It is sometimes desirable to obtain an average test of the milk from a whole day’s delivery. This can be obtained in two ways: First, by taking a sample from each patron’s milk with a sampling-tube, and putting it all together in one jar. The result represents an average test, pro- viding the samples have been correctly taken. Second, an aver- age test can be had by boring a small hole in the conductor-head. When the milk passes over this hole, a small portion of it drops through. A vessel of some kind can be put underneath to catch the drops. Such a drip-sample will represent very accurately the average quality of the milk received at the creamery. If it is desirable to keep this sample, a preservative can be added to it. Composite Sampling without the Use of Preservatives.— Pipettes can be obtained holding 5.87 ¢.c. of milk. These are one-third the size of the ordinary 17.6 c.c. pipette used for the Babcock test. With this small pipette a sample may be taken every day from each patron’s milk, during three suc- cessive days, and emptied into the same test-bottle each day. At the end of three days the samples may be tested and the bottles cleaned, ready for use again. Accurate composite samples may be obtained in this way, providing the sample in the pipette is correctly taken each day. No preservative is needed. The preservatives are added to the composite samples to prevent curdling. The test-bottles may be placed on a shelf, or preferably in a rack made to hold them. They should be marked in such a way as to identify them. A good way is to mark them the same as the com- posite jars, the number on the jar corresponding to the number on the milk-sheet for each patron. CHAPTER IX. CREAMERY CALCULATION. Find the Average Per Cent of Fat.—In calculating the average per cent of fat from a number of cows, or the milk furnished by the different patrons, the mistake of adding the tests of all the samples together and dividing the sum by the total number of samples tested is often made. Milk from different patrons, or from different cows, will always vary, some in quality and some in quantity, and in order to get a correct average test, both quantity and quality must be taken into consideration. The wrong way of calculating the average percentage may be illustrated as follows: Sample. Milk Delivered. Per cent Fat. 1 50 Ibs. 5.0 2 100 ‘‘ 4.5 3 500 <‘‘ 3.0 4 300 ‘‘ 3.5 4)16% 4 The average test, according to the wrong method, =4%. The correct way of calculating the average percentage may be illustrated as follows: Sample. Milk Delivered. Per cent Fat. 1 50 Ibs. 5.0= 2.5 Ibs. fat 2 100 ‘‘ 4.56= 4.5 « 3 500 ‘‘ 3.0=15.0 ‘* <«§ 4 300 ‘‘ 8.5=10.5 “ ¢F 950 Ibs. 950)32.5 Ibs. fat 3.42 105 106 BUTTER-MAKING. The average test, according to the correct method, is 3.42%. It will be seen from the example quoted that there is a difference of more than .5%. If the percentage of fat or the number of pounds of milk is uniform, then it does not matter which of the two ways illustrated above is used. But as uniformity in either of these respects scarcely ever exists in practice, the only correct way of calculating the percentage is to find the total number of pounds of fat and divide it by the total number of pounds of milk; the result is .0342, which may be written 3.42%. J 70 Fic. 63.—A Russian co-operative creamery in Siberia. (U. 8. Government Bulletin.) It is very common for creamery patrons to test the milk from each of their cows, then add the tests together and divide by the total number of cows tested. The result they will call the average test, and frequently such tests are made use of as evidence against a creamery operator to prove that his tests at the creamery were not correct. The fallacy is evident from what has been said above. CREAMERY CALCULATION. 107 The same mistake is also likely to be made in finding the average test from several creamery-plants and skimming- stations. Calculation of Overrun.—The amount of overrun is the difference between the amount of pure butter-fat, and the amount of butter manufactured from that given amount of fat. This difference, divided by the amount of fat and multi- plied by 100 will give the percentage of overrun. The calcu- lation of the overrun in the creamery should always be made Fic. 64.—A Cheshire creamery, England. (London Creamery Journal.) from the fat-basis on which the patrons are being paid. If the fat is delivered in the cream, the overrun should be calcu- lated from the fat in the cream. The overrun calculated from the composition of the butter manufactured would not be an indication of the correct overrun, as there might be serious losses of fat sustained during the different steps in the manu- facture, such as from inefficient skimming, incomplete churning, and general losses in the creamery. It is possible that butter might show a high content of the substances not fat, and yet not show a good overrun on account of losses; while butter containing only a medium high moisture-content might show as great or greater overrun on account of thorough and efficient work during the different steps of manufacture. 108 BUTTER-MAKING. The amount of overrun depends upon: 1. Thoroughness of skimming. 2. Completeness of churning. 3. General losses in the creamery. 4. Composition of the butter manufactured. The theoretical overrun, however, may be quite accurately calculated from the composition of the butter manufactured in a well regulated creamery. In creameries where the con- ditions of separation and churning are almost perfect, the amount of fat lost in the buttermilk and the skimmed milk is quite constant from day to day, and should not exceed .1% in the skimmed milk and .2% in the buttermilk, according to the Babcock test. Basing the calculations upon the above figures, the theoretical overrun may be calculated from the composition of the butter as follows: If, for instance, we start with 1000 pounds of milk-testing 4% fat, there will be a total of 40 pounds of fat. If we skim 32% cream from 4% milk, we should have +5, or 4, of it cream, and the remainder skim-milk, or 125 pounds of cream and 875 pounds of skimmed milk. If there were .1% of fat in the skimmed milk, there would be a loss of .875 pounds of fat during skimming. There would then be 39.125 pounds of fat in the 125 pounds of cream (40—.875=39.125). If 10% of starter were added to the cream we should get 137.5 pounds of cream testing 28.4%. (125 pounds cream x 1.10= 137.5 pounds cream; 39.125 +137.5= 28.4% fat.) By churning this cream we should obtain about 100 pounds of buttermilk. If it tested .2% fat there would be a loss of about .2 pounds of fat, making a total loss of fat in skim-milk and buttermilk of 1.075 pounds. Subtracting this total loss of 1.075 from 40 pounds we would have 38.925 pounds of fat left to be made into butter (40 —1.075= 38.925 pounds of fat). If the butter on analysis proves to contain 82% fat, the total number of pounds manu- factured will be 38.925 +82= 47.47 pounds of butter. 47.47 — 40= 7.47 pounds theoretical overrun, and 7.47 +40 x 100= 18.7% overrun (theoretical). CREAMERY CALCULATION. 109 It is evident that the losses of fat will vary according to the different conditions. The richer the cream, and the less fat in the whole milk to be skimmed, the more skim-milk there will be; the thinner the cream, and the more fat there is in the milk to be skimmed, the less skimmed milk there will be, and consequently with the same skimming efficiency less fat will be lost in the skim-milk. The thinner the cream is the more buttermilk there will be. These conditions must be left for the operator to govern according to the conditions present. The actual amount and per cent of overrun as determined in creameries is calculated as described previously. The formula is as follows: —— <100=per cent of actual overrun. Calculation of Churn-yield.—Instead of expressing the in- crease of butter over that of fat in the percentage overrun, as above, it is often customary among creamerymen to speak of the ‘‘churn-yield.”” For instance, they say that their test was 3.90, and their churn-yield was 5, meaning that on the average each 100 pounds of milk contained 3.9 pounds of fat and yielded 5 pounds of butter. The churn-yield is always expressed in percentage, and is obtained by dividing the total pounds of butter obtained by the total pounds of milk from which the butter was made, according to the following formula: Pounds of butter ; Pounds of milk 100 =churn-yield. In case cream is handled instead of milk, the same may be obtained by substituting “pounds of cream” for ‘‘ pounds of milk” in the formula. Calculation of Dividends.—The method of calculating dividends will vary according to the agreements between the manufacturer of the butter and the milk and cream producers. 110 BUTTER-MANING. Some manufacturers agree to make the butter for so many cents per pound of butter (usually 3 or 4 cents). Occasionally the creamery proprietor agrees to pay a final fixed sum for milk delivered containing a definite amount of fat (usually 47%). These two methods are not in use much at the present time, although in the eastern part of the United States the method of paying the operator so much per pound of butter-fat manu- factured is quite common. Fic. 65.—Jeinsen creamery, Barnten Province, Hamburg, Germany. (Creamery Journal.) The two methods most commonly used, especially in the central West, are as follows: (1) Pay so much per pound of butter-fat based upon some standard market price, such as Elgin or New York. The amount paid now by the central plants for butter-fat is usually 2 or 3 cents per pound below ‘“‘New York Extras,” and the company pays all freight or express charges. (2) Pay per pound of fat based upon the net income of the creamery. CREAMERY CALCULATION. 111 1. The former method of paying for butter-fat has become quite common. Nearly all the hand-separator or central plants are paying for butter according to this method. Payments are usually made every two weeks. Although this causes more work, it is much more satisfactory to the patrons than to pay only at the end of each month. In order to calculate dividends when paid at the end of two weeks or at the end of each month, the first step is to find how many pounds of butter-fat have been delivered by each patron. If composite samples are taken, and these tested for fat at intervals of one week, which would make about four tests during the month, and two during half a month, the results of the several tests may be added, and the sum divided by the number of samples tested. This may give the average test, but it must be borne in mind that this method is also likely to give wrong results. Especially is this so when cream is delivered which varies in quantity as well as quality during the different parts of the month. If cream only is being received, it is a good plan to test each patron’s cream every day, as it is more or less difficult to get absolutely accurate composite samples from creams of different richness. Besides this, the patrons can get the test as well as the weight of the cream of each previous day’s de- livery, and thus know how their account stands from day to day. A little more labor is involved in doing this, but in the long run it keeps the patrons better satisfied. 2. If the price of butter-fat per pound is being based upon the net income, as is the case in nearly all co-operative cream- eries, and also in many proprietary creameries, the first step is to find out how much butter-fat each patron delivered during the specified time,— two weeks or a month, whichever may be the case. When this has been obtained, the total pounds of fat delivered by all the patrons are found. From the gross income the total expenses of running the creamery are sub- tracted. The remainder represents the net income. This is then divided by the total pounds of fat delivered to the cream- raat ‘geoq Aq possaryap yur [Py “uoaIG¢) ‘Arora Avg soog—'99 ‘pry CREAMERY CALCULATION. 113 ery, and the quotient represents the price per pound of butter- fat to the patrons. Knowing the price of one pound of fat to be paid to the patrons, the sum due to each patron is found by multiplying the price per pound by the total number of pounds of fat each patron delivered during the specified time. In some instances provisions are made for a “‘sinking fund.” This is a name given to a fund raised by deducting so much per pound of fat, or per 100 pounds of milk, from each patron’s delivery at the end of each month. This fund is for the pur- pose of paying off a debt gradually, or for raising a fund for new equipment, or other improvements in the creamery. In case such money is to be withheld, it is deducted previous to making the final calculation. Cream-raising Coefficient.—By the term cream-raising coefhi- cient we understand the percentage of fat removed from the milk during the process of separation. The calculation of the cream-raising coefficient may be illustrated as follows: Suppose we have 100 pounds of milk containing 4% fat, and yielding 85 pounds of skim-milk and 15 pounds of cream, the skim-milk containing .2% fat. Total fat in whole milk =100 lbs. x4% =4 lbs. Total fat in skim-milk = 85 lbs. X.2°> =.17 lbs. Total fat in cream = 4 |bs.—.17 lbs. =3.83 lbs. S88 <1 onm5e? of the total 4 pounds of fat, or the 4 cream-raising coefficient. Statement to Patrons.—A complete statement should be made each time a settlement is made, and accompanied with the check. A statement similar to the following one may serve as an example: * * Creamery Butter-making, by Michels. 114 BUTTER-MAKING. CREAMERY COMPANY IN ACCOUNT WITH Mr. For the month of. 190___ Cr. Dr. No. pounds milk delivered Pounds butter........ Ab: sess Bee< byYOU «4 oe we Babette Cans: ate & go %. a) aeeeaneees Average test .. cae ERS Cash. 5. 6 cs. ee a dete cies No. pounds butter-fat . Ss isabegaer ate Hauling at ... ‘pet 100 Ibs: ica 2se% s Price per pound . . $........ : ee ee Balance due you. . . ewe a Se Oe a Bisgeesdics Total pounds milk delivered ‘at pleaiany. ee ee ee Average test at creamery ee ee ee ee Total pounds butter-fat at creamery HORE Be doe a Geedseoatsies if =< Ibsyabe es les Ce Beets | or eee Sales of butter { ane Ue ee $ ; res SY ee ale Cees: Less cts. for making. Balance due patrons flow Galo oy ee Boe Bleek ees Per cent oyermin.s- ¢:.% 4 % HS. SL Ow OE ite eles Testing witnessed by. Prest, Secy. At the end of the year a final statement should be made by the respective officers, similar to the following one: ANNUAL REPORT. Incorporated.......... 190... | Commenced Operations,.......... 190... baited eset ws Annual Report, 190.. of the CREAMERY COMPANY of ‘ Towa. ¢ Butter-maker; Asst. Butter-maker) CapiraL STOCK $............6+ Paiw IN $.............. OFFICERS AND DIRECTORS. President, Secretary, Treasurer. CREAMERY CALCULATION. 115 SECRETARY’S REPORT. To the Stockholders: Your Secretary herewith submits the following report for the year ending December 31, 190... Total pounds of milk received . . 2 oMhe Gaorsth ae ngs . tle teat Total pounds butter-fat contained in same Bas Sig l. 6 Tafeedhases Total pounds butter manufactured __. S bebseae cee Average test of butter-fat per hundred pounds Oi nnlG i hi see Average yield of butter per hundred pounds of milk. . . — .......... Average price paid per hundred pounds of milk GA: Geeoemees Average price paid per hundred pounds of butter-fat_ . a SM Seanad Average per cent increase of churn over test (overrun). . —.......... Average price received per pound of butter ee ee ee Average monthly expenses of running creamery. . . . . ..--eeeeee Average cost of manufacturing butter per pound. . . So. Asien givens Following is a Monthly Statement for the year 190... January ¢ . Be 2, 1% &. sea Mii Bades Bldeeeees February & Gok &. bk & Oe OR rN ees March... . . gl. Sapls & oo RD Sd cae 10d lig” senescent April . .. a ee . i a Mag enn sees Maye ws Gio, Ge a ae a ee 3 Raed ae eee DUNE! 52 Se 9 ope es Uy a at 0 BAS Kak, ome "°° “Avene dagealan DAY soe de

Giclsl: eS shawes i 116 BUTTER-MAKING. TREASURER’S REPORT. To the Stockholders of the Creamery Company: Your Treasurer herewith submits the following report: SraTEMENT OF CaSH RECEIVED AND DISBURSED. REcEIPTS. DISBURSEMENTS. Total . 52 Sel. whademalettes Total. 3 2 wa. 42aeesem% Respectfully submitted, , Treasurer. , Cashier of Bank. REPORT OF AUDITING COMMITTEE. To the Stockholders of the Creamery Company: We, the undersigned, appointed by your Board of Directors to examine and audit the Books, Accounts, and Vouchers of the Secretary and Treas- urer of the___ Creamery Company for the year 190..., hereby certify that we have carefully examined the same and compared them with the above reports of said officers, and find them correct. In witness whereof we have hereunto set our hands at, , Iowa, this .... day of ...... A.D., 190.... Auditing Committee. Paying for Fat in Cream Compared with Paying for Fat in Milk.—It is evident that when patrons deliver fat in the form of milk the creamery operator sustains a loss in the skimmed milk, while if the fat is delivered in the form of cream, no fat is lost in the skim-milk at the creamery, and consequently the cream patron should receive more per pound of fat delivered than the whole-milk patron, providing the quality of the fat in the cream is as good as that in the form of milk. The butter- maker should obtain a larger overrun from the fat of the cream than he does from the fat of the milk. The amount which the patrons should be paid for fat, delivered in the form of cream, depends upon the thoroughness of skimming. If 1000 pounds of milk testing 4% fat were bought and skimmed, there would be a loss of about .9 of a pound of fat during the skimming, which would make about 1 pound of butter, worth about 20 cents. If bought in the form of cream this loss would not be sustained. The above loss, during skimming, according to the figures mentioned, would amount to about half a cent CREAMERY CALCULATION. 117 per pound of butter manufactured. The fat lost during the skimming process would amount to about 2% of the total fat. If the cream fat be increased by 2%, an approximate basis for paying milk and cream patrons is obtained. Degree of Justice in Paying Cream Patrons More per Pound of Fat than the Milk Patrons.—There is another side to this question of reaching an equity of payment between the cream patrons and milk patrons. A cream patron should not receive more pay than a milk patron, unless the quality of the fat is as good as that delivered by the milk patron. It is a well- known fact that the fat delivered in the form of cream is, as a rule, and has been, much inferior to that delivered in the form of whole milk. This is evidently due to the fact that cream is not delivered daily to the creamery, and that it is improperly handled on the farm, and during transportation. According to the results obtained in the Iowa Educational Contest, and other scorings, butter from hand-separator cream on an average seldom scores above 90, on a scale of 100. It is safe to come to the conclusion that there is at least a difference of three points in quality in favor of creamery butter made from milk-fat. Mr. Healy, one of the best known butter judges, claims that in the near future butter will be sold more accord- ing to quality than it is now. He asserts that a fair basis of paying for butter according to scores would be to deduct a quarter of a cent for every point that the butter scores below 91, and an addition of a quarter of a cent for every point it scores above. This would make a difference of three-quarters of a cent per pound in the selling price of butter made from whole milk and that made from hand-separator cream. It was figured above that the loss from skimming would amount to about half a cent per pound of butter, thus leaving a margin of one-quarter of a cent in favor of the whole-milk patron per pound of butter, rather than being in favor of the cream patron. CHAPTER X. HEATING MILK PREVIOUS TO SKIMMING. Reasons for Heating.— Owing to the fact that all separators will skim closer and not clog so easily when milk is heated, nearly all creameries heat or warm the milk previous to skim- ming. By thus heating and stirring the milk in a pure atmo- sphere, many undesirable odors or taints escape. With an increase of temperature, the viscosity of the milk is lessened, due chiefly to the softening and separation of the fat-globules. Such an increased fluidity of the milk lessens the resistant force of the fat-globules when exposed to the centrifugal force of the separator. The higher the temperature the more fluid the milk becomes, and consequently the easier the fat can be separated. By warming the milk to a high temperature and leaving it for some time, and then cooling quickly again to skimming temperature (90° F.) and separating, the skimming efficiency of the separator is increased materially. If the milk has been standing at a very low temperature for at least three hours, and then is quickly warmed up to the usual skimming tem- perature, and skimmed, the warming of the milk has com- paratively little effect in bringing it into a good condition for skimming. It will thus be seen that it is possible to skim milk at the same temperature, and yet get different results, due to previous temperature conditions. Duration of tem- perature should be considered as well as the temperature itself. The temperature to which milk should be heated previous to skimming varies according to different investigators. The temperature that has been mostly employed in the past in 118 HEATING MILK PREVIOUS TO SKIMMING. 119 this country, and perhaps at the present time, is about 90° F. This comparatively low temperature was fixed owing to the supposedly bad effect high skimming temperature had upon the body of the finished butter. Exposing milk, at high tem- peratures, to the centrifugal force in a separator was said to producea greasy body in butter. According to some ex- periments conducted at the Iowa Experiment Station by the authors during the year 1902, milk can be skimmed at 175° F. without any injury to the quality of the butter, providing the cream is cooled to ripening temperature, or below, as soon as it has been skimmed. After the ripening has been com- pleted the cream should be exposed at least three hours to a low temperature (50° F.) previous to churning. If the milk is heated in any of the best modern heaters, no injurious results to the quality of the butter will be obtained. Prof. Dean, at the Ontario Agricultural College, has also found it practical to heat to pasteurization tempcrature previous to skimming. In many creameries in Denmark this method of heating milk is also followed. The Danes, as a rule, however, have the heated milk pass over a cooler before it goes into the separator. The chief difficulty encountered by the authors in heating milk to such a high temperature previous to skimming, was_ that the upper bearing in the separator got so hot that it was deemed injurious to the separator, although the bearing did not heat to such an extent as to cause the running of the machine to be abnormal in any way. Advantages of Warming Milk to High Heat Previous to Skimming.—The advantages of heating milk to a high tem- perature (175° F.) previous to skimming, may be summarized as follows: (1) Undesirable taints are eliminated from the milk to a greater extent than can be accomplished in any other way, without applying chemicals. (2) The heating of whole milk destroys the germs in the resultant skimmed milk and cream practically as efficiently rat (Ry ‘TaypeAy ye Atawvarg) “Aaouryovur jo yuawesuvse pood v Buraoys ‘wool-sioyvivdas vB Jo JoUIOD W—'19 ‘SIT HEATING MILK PREVIOUS TO SKIMMING. 121 as when heated after the skimming process has been com- pleted. (3) Less heating and cooling apparatus is necessary. (4) Closer skimming. How Heated.—There are two methods by which milk is heated previous to skimming. First, by the use of direct live steam; second, by the use of heaters which heat with steam or hot water indirectly. Fic. 68.—The Twentieth-century milk-heater. Heating of milk with direct live steam is accomplished in two ways: first, by entering a steam hose into the vat full of milk; and, second, by making use of special heaters, which allow steam to come in direct contact with the milk as the milk passes through. The method of heating milk with direct live steam cannot be too strongly condemned, because it leaves bad effects upon the flavor of the butter. At the Milwaukee National Butter contest in 1903, where over eight hundred exhibitors were represented, the authors noticed that where the criticism “burnt, oily flavor” was made on the score card, the milk from which the butter was made had in most cases been heated with live steam. The burnt flavor may possibly be due to the sudden excessive heat to which the milk will be exposed when coming in .contact with live steam. The greatest danger, however, in heating milk with live steam is, that impurities from the pipes and boiler are likely to be transmitted to the 122 BUTTER-MAKING. milk, and cause bad flavors. In most of the creameries the exhaust-steam from the engine is used to heat the water for the boiler. This steam is likely to carry with it cylinder-oil, which will impart undesirable flavors to the butter. Some creameries are also using boiler compounds for the removal of scales. These, when subjected to high heat and pressure, are likely to be transmitted to the steam-pipes, and from there with the steam into the milk. The scale and rust of steam-pipes are also likely to be transferred to the milk. The right way to heat milk previous to skimming is to make use of one of the special heaters on the market, which heat by the use of steam or hot water indirectly. CHAPTER XI. SEPARATION OF CREAM. In the process of the manufacture of butter it is essential that the fat of the milk shall be concentrated into a compara- tively small portion of the milk-serum. This concentration of fat carries with it a portion of all the other milk constituents, and the product is called cream. It is possible to churn milk without any separation, but a much greater loss is attendant, if the fat is not brought together by the process called separa- tion. The different kinds of cream may be classified according to the different methods of cream-separating: Deep-setting cream. Shallow-pan cream. Water dilution cream (hydraulic). Hand-separator cream. Gravity cream,.... Cream Creamery-separator cream, Centrifugal cream . . { GravITy CREAMING. Shallow-pan System.—This method of creaming is used mostly on farms which are situated unfavorably in relation to a creamery, or for some other reasons do not send their milk to the creamery. It consists in placing the milk in shallow pans, from 2 to 4 inches in depth, as soon after milking as possible. The milk is then placed where it can be quickly cooled to a temperature of at least 60° F. A lower temperature than this is desirable if conditions permit. The atmosphere in the room in which the milk is standing must be pure, free from dust, 123 124 BUTTER-MAKING. draught, and any undesirable taints or odors, since it takes about thirty-six hours of quiet standing for the cream to rise. If there is a constant current of air in the room, a leathery cream is likely to form. At the end of this time the cream is removed by the use of a skimmer, made especially for this purpose. It is difficult, however, to remove all the cream by this means. If the conditions are such that cool water can be constantly circulated around the pans containing the milk, the tempera- ture can easily be made to go below 60° F., and the creaming process is facilitated. When such conditions are present, the depth of the milk in the pans can safely be increased to about 6 inches. Under the most favorable conditions about .5% fat will remain in the skimmed milk. Deep-setting System.—This system is undoubtedly the best method of gravity creaming When properly carried on the "| fat can be removed so completely that no more than .2% of fat remains in the skimmed milk. It consists of put- ting milk into deep cans (ordinary four- gallon shotgun cans are usually em- ployed) immediately after the milk has been drawn from the cow. Then it is put into cold water, and generally : cooled down to, and maintained at, a Fic. 69.—Cooley creamer temperature of about 55° F. The and elevator. . 3 : cream will rise in about twenty-four hours. Better results can be obtained if the water is cooled down to about 40° with the use of ice-water. One reason why this system is in use so much, even in creamery localities is that the cream obtained is nearly always of a good quality. The farmer knows that unless the milk be cooled quickly, and maintained at a low temperature, the cream will not rise freely. For this reason the milk is syste- matically and thoroughly cooled, which is one of the great essentials in order to check the growth of the ferments in milk SEPARATION OF CREAM. 125 and keep the milk in good condition. In many parts of the eastern United States, the deep-setting system is in general use. A special form of can is used. The can is simply an ordinary four-gallon can, about 8 inches in diameter and 20 inches deep. It has a glass on one side near the bottom or near the top, which allows the reading of the thickness of the layer of cream. On each side of the glass is a graduated scale, which gives the reading in inches. In case the cream is being sold to a creamery, the hauler comes along, notes the depth of the layer of cream, and records the number of inches of cream opposite the patron’s name. At the end of the month, or whenever the time for payment comes, the money is appor- tioned according to the number of inches of cream delivered by each of the patrons. No test for fat is made. This is what is known as the ‘‘Cooley system,” and is used quite extensively in the East, especially in Massachusetts. While cream usually arrives at the creamery in a fair con- dition, there is the objection that the cream is always thin. It seldom contains any more than 18 or 20% of fat. No good explanation has yet been given why cream in a deep layer of milk at 40° F. should rise more quickly and more completely than in a thin layer at a higher temperature. * Arnold seeks to explain it by saying: ‘‘ Water is a better conductor of heat than fat; hence when the temperature of the milk varies either up or down, the water in the milk fcels the effect of the heat or cold sooner than the fat in the cream does. Therefore the cream is always a little behind the water in swelling with heat or shrinking with cold, thus diminishing the difference between the specific gravity of the milk and cream when the temperature is rising, and increasing it when the temperature is falling.” This explanation is, according to Babcock, not satisfactory. He says: ‘“ Though it is true that water is a better conductor of heat than fat, the small size of the fat-globules renders it * American Dairying, p. 210. { Wisconsin Experiment Station, Bull. 18, p. 24. 126 BUTTER-MAKING. impossible that under any circumstances there can be more than a small fraction of a degree of difference between the temperature of the fat and that of the milk serum. More- over, with the limits of temperature practical for a creamery, (90° to 40° F.), the coefficient of expansion of butter-fat is more than three times as great as that of water, so that in order to maintain the same relative difference in their specific gravities when the temperature is falling, the milk serum must cool nearly three times as quickly as the fat. In other words, when the milk serum has cooled from 90° to 40°, or 50° F., the fat-glabules should have lost less than 17°, and should still have a temperature of over 70° F., a difference between the temperature of milk serum and fat of more than 33°. Such a condition is manifestly impossible, but no less difference than this would cause the fat to become relatively heavier than at first, and would operate against the creaming.” A low temperature increases the viscosity of the milk, and consequently it would seem that the resistant force of the fat-globules in their upward passage through the milk serum would be increased, and thus retard the creaming. Babcock maintains that fibrin is partially precipitated when milk is allowed to stand at a medium high temperature. The fibrin, when precipitated, forms a fine network of threads permeating the milk in all directions, similar to the network of fibrin in coagulated blood. It is possible to conceive that such a network would interfere with the rising of the fat-glob- ules, at comparatively high temperatures. The reason that fat-globules will rise more quickly and more completely in the deep-setting system than in the shallow-pan system, might be explained on this fibrin theory were it not for the fact that experiments conducted at the Cornell Experiment Station show that the setting and cooling of milk may be delayed long enough for this fibrin to form, without any effect upon the separation when set and cooled. Probable Explanation.—It is a well known fact in physics that most liquids, when present in the form of drops, increase SEPARATION OF CREAM. 127 their surface tension when the temperature is lowered. Owing to this increase in surface tension, the liquid drops unite together at a low temperature much more rapidly than they do at a high temperature. For instance, two drops of molten iron unite much more readily just previous to solidifying than they do while the temperature is higher, and the liquid more fluid. As the fat in milk is present in the form of small liquid globules, as mentioned previously, it seems probable that these fat-globules might have properties similar to those of the liquid mentioned above, and behave similarly in the milk, when set at low temperatures, in accordance with the deep setting method. If the fat-globules act in accordance with this theory, it seems probable that there is no real membrane, other than that resulting from surface tension, enveloping each fat-globule. If there were such a membrane, composed of albuminoid chiefly, then undoubtedly the fat-globules would not assume this property. With such a deep layer of milk the lower most fat-globules must evidently encounter a great many other globules as they rise. If the physical force mentioned does not facilitate the process of uniting the globules, they would partly unite without it. The more they unite in small bunches, or masses, the greater would be the tendency for them to rise, as explained previously, and more of the smaller fat-globules would be carried along. The bottom globules would tend to partly unite and form a filter, which passes up through the milk by the buoyant force, or force of levity. If this latter explanation holds true, then more of the milk constituents would be present in the cream from the deep- setting system than in the cream from the shallow-pan system. By comparing the cream raised by the shallow-pan system with that raised by the deep-setting system, before the cream has been removed from the milk, it will be noticed that the cream raised by the shallow-pan system appears to be much yellower than is that raised by the deep-setting system. This condition can only be due to the fact that the surface cream, 128 BUTTER-MAKING. raised by the shallow-pan system, contains more pure fat. The fat, as it rises, does not have the same opportunity of uniting with so many other globules, owing to the comparatively shallow layer it has to pass through, and the temperature is not low enough to facilitate the uniting of the globules; that is, providing the fat-globules act the same as most other liquids at lower temperatures. Water-dilution Cream (Hydraulic)—When milk is diluted with water, the fat or cream rises much more rapidly and completely to the surface than it would in its undiluted form. A creaming-can is based upon this principle, and it was expected to combine quickness, efficiency, and simplicity. The sepa- rator consists simply of a tin can into which the milk is poured and then diluted with cold water. In a few hours the cream rises to the surface. Arrangements are usually made so that the skim-milk can be drawn off from the bottom of the can. While the diluted form of the milk apparently causes the creaming to be more efficiently and quickly done, it can readily be seen that in order to have a skimming efficiency equal to other methods of skimming, it must leave only about half as much fat, because the milk is diluted with about an equal volume of water. If the water-diluted skimmed milk contains .2% fat, then the same skim-milk in the undiluted form would contain .4 per cent fat. The water-dilution method of skimming practically spoils skimmed milk for feeding purposes. Skimmed milk which contains a fourth or a half of water, has been robbed of its essential relish to the calf, and it becomes necessary for the calf to consume too much volume in order to get the required amount of nourishment. This water-dilution system also gives more volume to handle. If farm dairying were conducted on a large scale, the method would not be practicable. Another objection is that the cream which results from this dilution method is seldom of good quality. Most well- water contains a multitude of micro-organisms which, when SEPARATION OF CREAM. 129 added to the milk, produce putrefactive and undesirable results. Much well-water also is tainted to a greater or lesser degree. Especially is this so with water from shallow wells. Butter made from cream which has been diluted with water usually has a flattish poor flavor. The efficiency of separation of diluted and undiluted milk is reported by Wing * to be as follows: Diluted with 25% warm water set at 60° F. (39 trials), 0.77% fat in skim-milk; Undiluted, set at 60° F’....... (30 trials), 1.00% fat in skim-milk Undiluted, set at 40° F....... (26 trials), 0.29% ‘‘ ‘¢ ee CENTRIFUGAL CREAMING. In the separation of cream by centrifugal machines, the same principle is used as in the gravity system of separation. The only difference is that in the centrifugal method the force which separates the cream from the milk is generated by artificial methods, and acts in a horizontal direction; in the gravity system the force which separates the cream from the milk is only that which results from the difference in the specific gravity of the cream and the skimmed milk, and the force acts in a vertical direction. The force generated in the sepa- rator is several hundred times greater than the natural force in the gravity method. For this reason the cream separates almost instantaneously after the milk has entered the separator and is exposed to the centrifugal force. Advantages.—The centrifugal separator has several advan- tages over the gravity method, which are apparent without detailed elaboration. In the first place, the range of tem- perature and condition of the milk at which the cream can be successfully separated is much greater than that for successful separation by the gravity method. Second, a much better quality of cream can be obtained by the centrifugal system, * Milk and Its Products, p. 105. 130 BUTTER-MAKING. as the separation can be done before the milk gets old, while by the gravity method the time required for efficient separation is so long that the cream deteriorates more or less before it is removed from the milk. Third, by the centrifugal method the thickness of the cream can be regulated to suit requirements, while by the gravity method the thickest cream that can be obtained is about 20%. Fourth, by the centrifugal method many impurities and undesirable germs are removed, while in the gravity method the exposure to open air more or less impure is likely to contaminate the milk with taints, and also allows the germs to fall into it. Fifth, by the centrifugal method the skimmed milk is left in an unadulterated condition. The milk can be skimmed soon after milking, or after it has been delivered to the creamery, and thus be in the best possible condition for feeding purposes. Sixth, the centrifugal method permits of a more thorough separation of the fat. Butter-fat, as arule, is too expensive to feed, when good and much cheaper substitutes can be had. History of Centrifugal Separators.—The first centrifugal separator was a very simple one. It consisted of buckets hanging on the ends of arms, or on the periphery of a rotating horizontal flat wheel which swung on a: central axis. The milk was placed in the buckets and whirled for a time, and then the machine (if we may call it such) was stopped, and the cream removed in the same way as in the gravity system. This method of separation, according to J. H. Monrad,* had its origin in 1864. As early as 1859 Professor Fuchs of Carls- ruhe, Germany, suggested testing the richness of milk by swing- ing tubes holding the samples of milk. In 1864 Prandtl, a brewer of Munich, separated milk by such a device. In 1870 Rev. F. H. Bond, of Northport, Massachusetts, worked out a method of separation which consisted of two small glass jars attached to a spindle making 200 revolutions per minute. By one hour’s whirling the cream came to the top. * Dairy Messenger, Oct., 1892, p. 109. SEPARATION OF CREAM. 131 In 1875 Prandtl exhibited at Frankfort-on-the-Main a con- tinuous .separator, which did not at the time attract much attention, due chiefly to the excessive amount of power needed to overcome the resistant force of the air. In 1876 a Danish engineer named Winstrup succeeded in improving the old bucket method. In 1877 Lefeldt and Lentch offered for sale four continuous separators with different capacities (from 110 to 600 pounds of milk per hour). During that year also the first practical centrifugal creamery was established at. Kiel, Germany. In 1877 Houston and Thompson of Philadelphia filed a patent for the continuous method of separation of cream MSS fil Fic. 70.—First centrifugal separator. (From Dairy Messenger.) from milk. The patent was allowed in 1891. In March, 1877, Lefeldt and Lentch invented a separator similar in construction to the hollow bowl—a more recent type. This machine did not revolve at so rapid a rate as our modern machines do, nor did it have arrangements for continuous inflow and discharge. It was intermittent in its work, and it was necessary to stop at intervals to remove the cream and skimmed milk. 1879 was the year which marked the greatest advancement toward the perfection of modern separators. The appearance of the Danish Weston, invented in Denmark, and the De Laval, in- vented in Sweden during that year, marked a great advance- 132 BUTTER-MAKING. ment in the separation of cream from milk. This led to con- tinuous milk and cream discharges, and consequently also to the continuous inflow of whole milk. These machines were of the hollow-bow! construction. Modern Separators.—Since the year when the Danish Weston and the De Laval machines were invented, many different types of separators with different contrivances within the bowl have been put upon the market. Baron Bechtelsheim, of Munich, is given the credit of having discovered that certain Fic. 71.—The United States separator. contrivances on the inside of the machine increase the efficiency and capacity of skimming. This discovery was made, accord- ing to J. H. Monrad,* in 1890. This invention was bought by the De Laval Company. The principal part of practically all the separators is a bowl rotating in a vertical position, with or without contrivances inside the bowl. Machines having a bowl rotating in a hori- zontal position are, so far as the authors know, not in use at the present time. Such a machine was once manufactured at Hamburg, Germany, and was called “‘Peterson’s Centrifugal * Dairy Messenger, Jan. 1892, p. 9. SEPARATION OF CREAM. 133 Machine.” Another German machine, called ‘‘The Page,” was also manufactured in the horizontal bow] style. From the above it will be noticed that four separate steps are recognizable in the evolution and improvement of separators: 1. Revolving Bucket Centrifuge; 2. Intermittent Hollow Bowl; 3. Continuous Hollow Bowl; 4. Continuous Separator with contrivances within the Bowl. Fic. 72.—The Simplex separator. The science and practice of separation of milk and cream have seemingly reached a high state of efficiency. It seems almost improbable, considering the many new improved sepa- rators on the market that any other great improvement could be made which would add a separate stage to the improve- ment of our best centrifugal milk separators of to-day. Classification of Separators.—Owing to the many different standard types of separators now on the market, it is impossible to describe each one in detail. For this reason the classifi- 134 BUTTER-MAKING. cation appearing below has been made. There are undoubtedly many other types, especially in foreign countries, with which the writers are not familiar, and which are not mentioned here. The following classification will, in some measure, illustrate the different makes of separators on the market to-day: { De Laval (old style). | Sharples. (Cause milk to pass in thin sheets vertical- ' ly in bowl. Hollow bowl... ( Omega. Empire. Davis. United States. National. | Reid. Farm sep- , arators. Separa- tors. L Contrivances in bowl. Cause milk to separate into almost hori- { zontal thin sheets. ( Dairy Queen. De Laval. Peerless. Swea. Westphalia (Cleveland). Towa. | Skim-close. iene Danish Weston (Reid). Sharples (old style). | De Laval (old style). Cause milk 4 Hollow bowl Creamery power separa- * tors, United States. Simplex. Sharples (new style). pass in thin sheets _ verti- cally in bowl. Contrivances in bowl. separate in al- | De Laval. Cause milk | Springer. } most horizon- | tal sheets. | Many of these separators which cause the milk to pass up and down in vertical sheets have the bowl contrivances corrugated, and perforated with holes so that the skim-milk and cream assume also a partly horizontal direction. Process of Separation.—From the illustrations, the structure of the more common types of separator bowls is readily understood. The whole milk may be made to enter at the bottom or top of the bowl when revolving. In the Sharples, the milk enters at the bottom. The more common way is to have the whole milk enter at the top. As the milk enters the bowl and is exposed to the centrifugal force, SEPARATION OF CREAM. 135 it immediately begins to separate into three distinct layers. The centrifugal force acting in a horizontal direction forces the heaviest portions of the milk and the precipitated albu- minoids, ash, filth, and a multitude of germs over next to Fig. 73.—The Reid separator. Fic. 74.—The Sharples separator. the wall of the separator bowl, and into a solid and more or less gelatinous layer, which is known as the “ separator slime.” In very impure milk this substance is so plentiful that it is likely to clog the separator in a very short time, and before much separation is accomplished it is necessary to clean out the bowl. The second layer is the skim-milk, while the cream, being the lightest, is forced to the center of the bow] and forms the third portion mentioned. There is no distinct line of demarcation between the layers of skimmed milk and cream. They overlap each other and form a sort of zone, rather than a sharp separation. The richest cream is nearest the center of the bowl, and gets thinner toward the outer portion of the bowl; consequently, by turning the outlet for the cream, or cream-screw, nearer the center of the bowl, the cream is increased 136 BUTTER-MAKING. inrichness. Turning it away from the center causes the cream to be thinner. The skimmed milk that is forced clear to the circumference of the bowl contains the least fat, and con- sequently the skimmed milk is always first removed from this portion of the bowl. Usually the skim milk outlet is brought in towards the center of the bowl at one end through tubes extending from the circumference of the bowl. If this were not done, some difficulty would be involved in arranging a BLO Fie. 75.—Showing “butter extractor” Fic. 76—Showing cross-section of attached to De Laval separator. The De Laval separator bowl. butter extractor is not known to be in use now. receiving-pan for the discharged skim-milk. If the skim- milk were discharged near the circumference of the bowl, it would come out with a heavy force. Also, if the outlet for the skimmed milk were near the circumference of the bowl, a great deal more power would be required to run the machine. As the skimmed milk passes through the tubes towards the center it gives up its force. The nearer the skimmed-milk outlet can be brought to the center of the bowl, the easier will the machine run. SEPARATION OF CREAM. 137 The size of the skimmed-milk outlet is usually made so that it bears a certain relation to the size of inlet, size of bowl, and to the speed of the machine. Most skimmed-milk outlets are made so as to discharge from .4 to about .9 or a little more, of the whole milk that enters the bowl. The remainder is the cream, which is forced to the center of the bowl and dis- charged through the cream outlet. ReELatTIvE AMOUNT AND RICHNESS OF MILK AND OREAM OBTAINED. The conditions which affect the relative amount of cream may be said to be as follows: 1. Regulation of the cream or skimmed-milk screw. 2. Rate of inflow to the bowl. 3. Speed of the machine. 4. Temperature of the milk. 1. Regulation of the Cream or Skimmed-milk Screw.—All modern machines, so far as known, have a device by which the relative amount of skimmed milk and cream can be con- trolled, and consequently the richness of the cream. Some machines have this device in the form of a cream-screw, and others as a skim-milk screw. The cream-screw in most of the machines has a hole on one side of it through which the cream is discharged. If this screw is turned so as to make the hole nearer the center, then the cream will be richer and less in quantity. If turned away from the center, then more and thinner cream will be discharged. In some machines there is a skim-milk screw which serves the same purpose. The method then of regulating the relative amount of cream and skimmed milk works in just the opposite direction; that is, when thicker cream and less of it is wanted, then the milk-screw is turned so as to bring the skimmed-milk outlet nearer the circumference of the bowl. This gives more skimmed milk and consequently less cream. If thinner and more cream is wanted, then the screw is turned in. This causes more milk to flow out through the cream outlet. The Reid hand separator 138 BUTTER-MAKING. is an example of this latter class. These two methods of regu- lating the thickness and amount of cream are the most common. It cannot be done while the machine is in motion. By some this is considered a drawback. Other separators have a device whereby the amount of cream can be regulated while the machine is in motion. For instance, on the improved Danish Weston, there is a screw attached to the skim-milk discharge-tube, by turning which the end or point of the tube can be made to be closer or farther away from the center, thus regulating the relative amount of cream and skimmed milk, and the thickness of the cream. 2. Rate of Inflow.—The rate of inflow of milk to the sepa- rator has a large influence on the relative amount of cream and skimmed milk. The greater the inflow to the separator, the more and thinner cream will be obtained, and with a dimin- ished inflow the less and thicker cream is obtained. This is due to the fact that at a given velocity of the machine the skim-milk discharge remains practically constant. So, if more milk is turned on, the only place where the discharge can increase is through the cream outlet; and if the inlet is diminished, the cream will diminish until a certain time, when the amount of milk, which runs into the machine, equals the amount discharged through the skim-milk outlet, and then there will be little or no cream. This is aptly illustrated by Wing: “If the milk is turned into the bowl at such a rate that .8 escapes through the skim-milk outlet, we shall have .8 skim-milk and .2 cream. If, now, we reduce the rate of inflow by .1, we shall get just as much skimmed milk as before, but only half as much cream; or, if the inflow is increased -1, we shall get the same amount of skimmed milk and one and a half times as much cream.” The completeness of sepa- ration will be the same so long as the separator is run within the range of its capacity. 3. Speed.—The speed of the separator influences the rela- tive amount of the cream and skimmed milk only in so far as an increase in the speed of the bowl increases the capacity SEPARATION OF CREAM. 139 of the skim-milk outlet, due to a more rapid discharge through the skim-milk outlet. The slower the bowl re- volves the less skimmed milk will be discharged, and conse- quently, if the inlet is constant, more and thinner cream will be the result. It should be stated in connection with this that the efficiency of skimming depends to a large extent upon the speed, and if attempts are made to increase the amount of cream and decrease the percentage of fat in it, by lowering the speed, an abnormal amount of fat will be left in the skimmed milk. 4. Temperature.—The temperature of milk usually does not influence the relative amount of milk and cream very much. The higher the temperature the more fluid the milk becomes, and consequently, all other conditions being the same, slightly more milk will run through at a high temperature than is the case with a lower temperature. This increase will show itself chiefly in the amount of cream, as the higher temperature has a greater relative effect upon the cream than it has upon the milk. By increasing the temperature of the milk, slightly more and thinner cream is obtained. ConpitTions AFFECTING EFFICIENCY OF SEPARATORS. 1. Manner of Heating Milk.—Owing to the fact that fat- globules rapidly change their shape and property by exposing them to heat and excessive agitation, it is essential that care should be taken in heating milk previous to skimming. When fat-globules are heated they become more liquid, and if stirred very much the clusters of fat-globules break up more rapidly. The individual globules, if stirred violently, will break or sub- divide into several small ones. The higher the temperature of the milk, the more fluid the milk becomes, and the easier the separation. If milk is stirred violently, the individual fat- globules break up into smaller ones, which are separated from milk with difficulty. The following table * illustrates what * Hoard’s Dairyman, Fort Atkinson, Wis. 140 BUTTER-MAKING. effect the different degrees of agitation of milk has upon the efficiency of separation: Av. Fat No. of Per Cent Experi- in ments. Skim- milk. Milk heated in vat, not pumped.................00 000s ee eee 10 =.117 Milk heated in Pasteurizer, 200 revolutions of Bentaton perminute 8 .115 “ce “e “ce be 250 es ce be 3 118 ce 6c ““ “e 300 ce be be ce ec 8 134 “ce oe be “ce 350 “6 be “ce ce “cé 2 143 ce ce ce ee 400 ce ce ag “e “ci 7 .198 tf ce oc“ ce 500 oe ce se ce ce 4 225 Milk pumped by the parting pump at 122° Bc ssvedecaners 3 .129 ee pee EG GAS Mia. cas alte ea beeen 3 119 ios «« with the pump, cHECIIRE BU 2D eis secs eatin Dies 3 .117 se ne ee ES ES Sn OA reac 8 ela taunt 3 .115 In the above experiments the diameter of the agitator in the Pasteurizer was 14 inches. The speed at the periphery, at 250 revolutions per minute, was 5 feet per second. It will be seen from the above table that the higher the speed of the agitator, the greater the difficulty in getting a complete separation. Besides the speed of the agitator in the heating apparatus, undoubtedly the shape of the Pas- teurizer is a factor in determining the efficiency of the subsequent separation. For instance, the milk in most hori- zontal Pasteurizers is, even at low speed, exposed to con- siderable agitation. If the milk is suddenly heated from a low temperature to about 80° or 90° F. and then skimmed, the heating does not facilitate the skimming process very much. It is essential that the milk should be exposed to this temperature for a considerable time. The fat-globules do not warm as rapidly as the milk-serum. This diminishes the difference between the specific gravity of the two substances, consequently complete- ness of separation becomes more difficult. If milk is heated to a high temperature, say, for instance, 170° F., then the separation will be sufficiently complete without exposing the milk for any length of time to that temperature. SEPARATION OF CREAM. 141 Machines are now made, and are on the market, which will bring the milk, or the fat-globules in the milk, into such a condition that they cannot be separated from the milk. The process is called “homogenization.” It consists of bringing the milk under certain pressure, and then forcing it out through a special valve. This relief, through this special valve, causes the fat-globules to divide up into very minute ones. They divide up to such an extent that they cannot be separated from the milk by gravity methods, and it is impossible to get a complete separation by centrifugal methods. Homogeniza- tion of milk is carried on to some extent in Europe. The process practically insures uniform quality to the milk patrons in the distribution of milk in cities, and secures a more uniform consistency of the product. 2. Condition of the Milk.—In order to get complete separation, and keep the separator in good running order, it is essential that the milk should be in as good physical condition as possible. Coagulated, slimy, or otherwise viscous milk separates with difficulty. When such milk is on hand it should not be mixed with the milk that is in good condition, as it might tend to coag- ulate more of the good milk, and the coagulated or slimy lumps are likely to clog the separator. Such milk should be left until all the good milk has been separated. Then, if the coagu- lated or slimy milk is thoroughly stirred so as to reduce the lumpiness of it, it may be run through the separator success- fully. It is a good plan not to feed the separator quite so heavily when this quality of milk is being run through. By shutting off the inlet a little, it will usually run through without clogging. Milk containing impurities in suspension should be thoroughly strained previous to separation. Overfeeding the Separator—When a separator is being overfed with milk there is a tendency for the machine to do less complete work. This is due to the fact that the more milk is being fed into the separator the less time it will be exposed to the centrifugal force. It is impossible to underfeed the separator as well. As has been mentioned before, the 142 BUTTER-MAKING. inlet can be closed to such an extent as to cause nearly all the discharge to take place through the skim-milk tube. As a rule when the machine has been set so as to allow the milk to flow in at a certain rate, it will continue to admit prac- tically the same amount of milk all through the skimming period. Among the conditions which may alter the rate of inflow to some extent, are the amount of heat and the change of pressure, due to different amounts of milk in the receiving- vat. Temperature will slightly affect the rate of inflow. The higher the temperature, all other conditions being the same, the more milk will pass through the inlet. 3. Speed.—All modern machines have a device by which their speed can be determined. Most speed indicators consist of a little wheel, which, when pushed up against the spindle of the separator while running, turns around and permits the calcu- lation of the speed of the separator. If the wheel on the speed- indicator turns 10 revolutions during ten seconds, the machine would turn 1000 times during the same time. During one minute the separator will run six times as many revolutions, or 6000, as ten seconds is one-sixth of a minute. Most speed- indicators are so adjusted as to turn one revolution for every 100 revolutions of the machine. The higher the speed, the more thorough is the separation. Nearly all machines are balanced to do the best work at a certain definite speed, varying with different machines, and indicated in the directions for operating. It is essential that the machine should be brought up to speed gradually, and no milk be allowed to flow through it until after it has acquired its full speed. During the run, all machines are likely to vary more or less in speed, owing to different causes. Pulleys are likely to slip on the shaft, and belts are likely to become loose, and thus cause variations in the speed. The steam pressure is likely to get low, and cause all of the machinery in the creamery to run more slowly. This cause, however, is not a very common one where belt separators are used. If the engine has an auto- SEPARATION OF CREAM. 148 matic governor on it, the speed is usually quite uniform. Where steam-turbine machines are used, the speed of the machine is more likely to vary with the different amounts of steam pressure on the boiler. With turbine separators it is very essential to keep an even steam pressure. Some turbine separators have a safety-valve attached to prevent too high speed. The reason why the prevention of a variation in speed is so essential is that a slight variation in the speed has a compara- tively large effect upon reducing or increasing the centrifugal force. The centrifugal force generated in a machine varies according to the diameter of the bowl, and according to the speed of the machine. The greater the diameter of the bowl, the less speed of velocity is required in order to get a certain force. The centrifugal force varies in direct proportion to the diameter of the bowl; that is, if the diameter of the bowl be doubled, then at the same speed, the centrifugal force has been doubled. The centrifugal force varies in quadratic proportion to the speed of the machine; that is, if the speed of the sepa- rator is doubled, the centrifugal force is increased four times. From this it will be seen that speed is a great factor in deter- mining the centrifugal force generated. It is not a good plan to have the diameter of the bowl too large, for the following reasons: A large bowl is more likely to be thrown out of balance; it is harder to keep on the bearings; and it is heavier and more unhandy to handle. For these reasons it is better to lessen the diameter of the bow! and increase the speed. This, of course, is true only to a certain limit. Steadiness in Running.—Smooth running of a separator is one of the first essentials. If a machine runs roughly, there will not be good separation, and it is dangerous to runit. The bowl itself is likely to jump out, or burst. The causes for unsteadiness in running are many. It may be due to a bent or sprung spindle; the machine not standing level; changing covers to bowls; using clamps which do not fit the bowl cover; unclean, worn-out bearings; condition of the bowl, and con- trivances inside the bowl; and dented and rusty bowls. Occa- 144 BUTTER-MAKING. sionally it happens that a machine is run backwards. This is likely to cause the cover of the bowl to run off. Thickness of Cream.—The efficiency of skimming depends to some extent upon the thickness of the cream skimmed. Most separators, however, will skim within quite a wide range as to thickness. The richness of cream usually skimmed by separators is about from 25% to 50%. Most separators, how- ever, will do good skimming even if the cream contains as high as 60% fat. This, however, should be considered to be about the maximum, in order to get the best results from a separator. Slush in Bowl.—As has been mentioned before, there is always a thick, slimy substance which adheres to the bowl- wall. The composition of separator-slime is, according to Fleischmann, as follows: Watetinnts: .cc.ckiawehtaie aiigudeseenan OTsd Wass as oe ae SOS, 1.1 Caseous matter. ..................2.2... 25.9 Other organic substances................ 2.1 AST pei Deir 2 deter ue 3.6 100.0 At the center of the bowl, or along the axis which runs perpendicular in the bowl, there is always considerable cream. It is practically impossible to get all the cream out of the bowl, even if it is flushed with much water. The amount of slush varies somewhat with the different kinds of separators. For this reason, it is essential that it should be taken into con- sideration when the comparative efficiency of skimming of different separators is considered. When the test extends over a comparatively long period, and the milk skimmed amounts to several thousand pounds, then the bowl-slush does not affect the conditions for comparative results very much; but when the test is short, and only a hundred pounds of milk, or a similar amount, is skimmed, then the amount of fat left in the bowl- slush will have considerable influence upon deciding which one is the most efficient machine. SEPARATION OF CREAM. 145 General Remarks.—In order to keep the separator in good running order, it must receive care. The belt should not be too tight, nor too loose. If too tight it is likely to bind, heat, and set the bearings of the separator. If too loose it is likely to slip, and to wear out more quickly. The machine should be well oiled. It is better to use a trifle too much oil than not enough. If a bearing is once heated, the machine will never run as well again. The bowl should be handled with great care. Bowls, or parts belonging to the bowl, can be kept from rusting by boiling them in water, or by steaming them thoroughly after they have been cleaned. If scalding-hot water is used before the milky portion has been washed off, the albuminoids will be scalded on to such a degree that it is difficult to get them off. This applies to all dairy and creamery utensils. Hot water is said to be best in which to dip tin or iron-ware after washing in order to keep them from rusting. If the bowl, pail, or whatever utensil it may be, is turned over to drain after being dipped in hot water, the heat taken up by the utensil will ina short time perfectly dry the apparatus. If the bowl is steamed, it should be heated thoroughly to make it dry quickly. If the milk supply gets short during the run, and it is neces- sary to run the machine without feeding milk, then the machine should always be flushed with luke-warm water. This will, in a measure, prevent clogging. Scalding-hot water should never be used for flushing the separator. The cream and skimmed- milk tubes should be carefully cleaned, with the special wire provided for that purpose, each time the machine is washed. The contrivances on the inside of the bowl should also be handled with care so as not to injure them in any way. They should be treated with hot water, as mentioned above, in order to keep them from rusting. When the bowl is not to be used for some time, it should be oiled well so as to prevent it from rusting. It is easier to oil a separator bowl than it is to scour the rust off later on. CHAPTER XII. FARM SEPARATORS. Tue conditions affecting the efficiency of skimming and the relative amount of cream and skim-milk described under “Creamery Separation’ apply to farm separators as well. The conditions under which the farm separators are operated war- rant a few separate remarks on this subject. Introduction of Farm Separators.—Small, or hand, separa- tors, have been manufactured for a good many years. It is, however, not until comparatively recent years that they have been numerous enough to be of commercial importance. The people in the Central West (Iowa, Kansas, Nebraska, Missouri, Minnesota, and Illinois) have been most prominent in intro- ducing farm separators. In the year 1894 hand separators were introduced in Iowa, but it was not until 1898 that they gained sufficient foothold to be of commercial importance. According to the Iowa Dairy Commissioner’s report of 1898, there were then only 904 farm separators in the state of Iowa. Now, in 1904, there are more than 17,000 separators. Glancing over the statistics it will be seen that the rate of increase in hand separators during the years intervening between 1898 and 1904 has been uniform and rapid. This proves that the dairy business is still in a transitional period, and the intro- duction of hand separators still on the increase. Such a time in any industry is always accompanied by more or less incon- venience, difficulty, and dissatisfaction. To receive a part of the butter-fat in the form of cream, and the other part in the form of milk, is undesirable. Under such a system it is always difficult to get milk or cream routes organized; proper sampling 146 FARM SEPARATORS. 147 becomes more or less difficult, and the quality of butter is harder to control. Reasons for Introducing Farm Separators.—It requires an investment of about $100 to purchase a hand separator. Fie. 77.—The Omega hand separator. Most of the butter made from hand-separator cream is of poor quality. Still, in the face of this, separators have rapidly -iu creased. It may be concluded that there must be some good reasons why farmers are continuing to invest in farm separators. There are undoubtedly many reasons why farmers prefer hand 148 BUTTER-MAKING. separators; reasons which are, to a large extent, confined to local conditions. Only a few of the chief and general reasons can be given here: (1) The farmer is able to skim the milk at once after it has been drawn, thereby enabling him to feed the milk while Fic. 78.—The Iowa hand separator. Fic. 79.—The De Laval hand separator (Baby No. 1). it is in a warm, sweet, unadulterated condition. If he hauled the milk to the creamery, the skimmed milk would be likely to come back in a sour and curdled condition, and at times watery. (In a well-conducted creamery these latter conditions do not exist.) (2) The high cost of hauling in many instances makes it almost impossible to get the milk to the creamery. Even if the roads are good, the distance to the creamery is frequently so great that it is impossible to get haulers, nor is it practical for every farmer to haul his own milk every day. Especially is this so during the busy season of the year. In the fall, when milk is scarce, it is almost impossible for the hauler to FARM SEPARATORS. 149 get enough milk to make it profitable. In many cases it is necessary to pay an excessive price for hauling milk. When cream routes are established instead of milk routes, one hauler can usually cover as much territory as three could Fic. 80.—Simplex hand separator and the different parts of bowl. under the milk system. Two thousand pounds of milk, testing 4% and containing 80 pounds of fat, would represent approx- imately a load of milk. At 12 cents per 100 pounds, this would mean a cost of $2.40 for getting that much milk 150 BUTTER-MAKING. hauled. If the same amount of butter-fat were hauled in the form of cream, it could be gathered for about 1} cents per pound of fat, or the cost of hauling in this particular case would be $1.20. Under the milk system it would be neces- sary to haul the milk to the creamery every day, while under the cream system it is usually gathered every other day in the summer, and every three days in the winter. It is usually considered that there is a saving of about 1} to 2 Fic. 81.—Sharples separator and parts of bowl. cents per pound of butter-fat in hauling, by making use of the cream system instead of the milk system. This, of course, would vary according to local conditions. 3. The use of hand-separators makes farmers more inde- pendent than they are under the whole-milk system. They are not compelled to support their local creamery unless they deem it advisable. They can ship their cream to any place that they may choose. If the butter from the hand-separator cream is going to be of as good quality as that made by the whole- milk system, the cream should be delivered as often as possible. Every day is preferable to every other day. In case frequent FARM SEPARATORS. 151 delivery is made, then it becomes quite essential for the farmer to patronize the local creamery, as very few farmers keep suffi- cient cows to get enough cream to pay them to ship by rail | Fic. 82.—The National hand separator and parts of bowl. every day. Usually it does not cost much more to ship a can full of cream than it does to ship it half or three-quarters full. 152 BUTTER-MAKING. Objections to Farm Separators.—Under the present manner of carrying on the hand-separator system, the quality of butter manufactured from the cream shipped into the central plants is much poorer than that made from whole milk. This is not due to ny fault of the system, but to the poor care which the separator and cream receive. The sepa- rator on the farm is frequently kept in an unsuitable place. Often it is located in the barn. If the milk is separated in such a place it will absorb odors and undesirable taints. The cream is seldom taken care of properly after it is separated. The separators often are not cleaned well. A separator can- not be kept in good condition by simply flushing out the bowl with cold water at the : end of each separation. It must be taken Fic. renee Laval apart at the close of each skimming; have all hand separator. the parts washed thoroughly in luke-warm water, and then scalded. The time and power it requires to skim the milk and to care for the milk is in many instances considered objectionable to the system. Thickness of Cream.—The thickness of cream which most butter-makers at central plants prefer is cream containing about 30 to 40% of fat. Such cream is not thick enough to cause any inconvenience in sampling and weighing. It can be diluted with a good starter and ripened without getting it so thin as to produce unfavorable conditions for churning. By some it is deemed advisable to skim even thicker than this, up to 50%. Cream containing this much fat, however, is difficult to handle especially in winter, during cold weather. It gets so stiff that it is difficult to pour, and there is also danger of losing more or less cream through its adhering to the sides of the cans. A thick cream is advisable from the farmer’s standpoint. The thicker the cream is, the more skim-milk he will retain on the farm for feeding purposes. It can also readily be seen FARM SEPARATORS. 153 that if thin cream is skimmed greater can capacity is necessary, and the express charges will be heavier than if the thicker cream were skimmed. Rich cream does not sour so rapidly as does thin cream. Fic. 84.—The Reid hand separator. Fic. 85.—Empire hand separator. The thickness of cream can be readily ascertained by the use of a Babcock test, which every farmer should have in his possession. A whole outfit for testing fat in cream or milk 154 BUTTER-MAKING. can be had for about $8.00 from any creamery supply-house- By the use of such a test, the farmer can test his cream and Fic. 86.—Peerless hand separator and cross-section of bowl. skimmed milk. He can also test the milk of each individual cow in the herd, thereby ascertaining which ones are profitable. Fie. 87.—Agos hand tester. By the use of such a test on the farm, the farmer can test his cream daily, and compare results with those from the creamery, FARM SEPARATORS. 155 thereby enabling him to detect any mistake which may happen at the creamery. Power for Farm Separators——Hand-power is often men- Fic. 88.—The Dairy Queen hand separator. Fie. 89.—Xcales. tioned as an objection to farmseparators. When a considerable quantity of milk is to be skimmed, it is certainly hard work to skim with hand-power. Windmills could not well be used ee Fic. 90.—Tread-power attached to United States hand separator. as they do not give uniform speed. The power must be steady and uniform. Farm separators are often run with tread- power. This kind of power is very applicable, and does not cost 156 20% BUTTER-MAKING. ical 25 % 30 % 40% Fig. 91.—Showing the height to which cream free from air-bubbles must be raised in a pipette to get 18 grams of cream. It shows that to measure cream in a pipette is inaccurate in Com. Report, 1903.) cream testing. (lowa State Dairy FARM SEPARATORS. 157 anything after the tread-power has once been purchased. The power can be supplied by using different kinds of animals. Fic. 92.—Showing how the internal bowl devices of Westphalia hand sepa- rator are washed. (N. Y. Produce Review and American Creamery.) Sheep, goats, dogs, and bulls are used for this purpose. The process usually does not last very long, and it is not considered heavy work. Steam is good power, but it is hardly ever obtainable on the farm. Small gasoline-engines are also used very successfully. The machine should always run smoothly in order to get efficient skimming. It should never be stopped and started with a jerk. Start it slowly and there will be less dan- ger of breaking any of the gearing parts. The bowl and inside parts should be kept from rusting as described previously on page 145. The bearings should be well oiled. It is a good plan to have an extra Fic. 93.—Davis hand separator. bearing or two on hand, so that if one happens to wear 158 BUTTER-MAKING. out another one can be put in. The bearings should be cleaned at intervals. When kerosene is occasionally used on the bearings they do not need to be cleaned so often, because ey . #2 el team eee ee Fie. 94.—Dairy utensils in the battered condition of the can on left and with tin off in many places inside, cannot be kept clean and should be discarded. (IXansas State Board of Agriculture Report No. 87, 1903.) it keeps them from gumming. The machine should be turned at the proper speed, as indicated in the directions. A thicker cream will result from rapid turning; consequently more skimmed milk will be obtained. Slow turning causes ineffi- cient skimming and thinner cream. Care of Cream on the Farm.—The first step in the produc- tion of good cream is clean milking. This can only be accom- plished when barn, cows, and utensils are clean. It is a good 6ST CTT ‘FS ‘Mep) “Bury orojoq ssappn soo Burreayy—'S6 ‘PY 160 BUTTER-MAKING. plan to dampen a cloth, and wipe off the cow’s udder and sides each time previous to milking. The milker should never wet his hands while milking. Dust should not be stirred up in the barn during milking, as the dust particles carry with them a large number of undesirable germs. When these settle in milk they are likely to produce taints. If cloth strainers are used they should be kept scrupulously clean. It is advis- able not to use them at all, as good sanitary wire-gauze strainers are inexpensive. Progeny of a single germ in © twelve hours Fic. 96.—Showing the efiect of cooling milk on the growth of bacteria. The beneficial results of early chilling are readily apparent. (From Bul. 62, Wis.) Tf these conditions are complied with, and the separator is kept in a good clean condition, the milk will have compara- tively few germs in it. Some germs, however, will enter the milk, and in order to keep them from developing, it is essential to cool the cream or milk immediately. Low temperature retards and practically prevents the development of germ life. It is a well-known fact that when milk is kept cool, it will remain sweet much longer than if kept at a high temperature. Never mix two milkings or skimmings unless both are well cooled first. In order to cool cream quickly, it should be stirred during cooling. The ordinary four-gallon shot-gun cans are good and suitable for keeping milk and cream. They have a large cooling surface in proportion to their cubical content. FARM SEPARATORS. 161 The milk or cream should be cooled as low as the water will cool it. It is well to cool it even lower than this if ice is ob- tainable. In keeping milk, the temperature should never go Tic. 97—The condition of the cow shown in this cut is favorable for the accumulation of loose dirt. (Bul. 84, IIl.) above 60° F. Cooling to 50° F., if it can be accomplished, is much more desirable for keeping milk or cream in good condi- tion. 162 BUTTER-MAKING. If considerable milk is handled, it is well to provide a milk- house. It should be built large enough to ccntain the sepa- rator, water-tank, and other utensils necessary for home butter- Fic. 98.—A clean cow. The dirt cannot adhere to this cow to so great an extent as to the one shown in Fig. 97. (Bul. 84, III.) making, such as a churn and butter-worker. There should be plenty of windows on all sides to give good ventilation. The water-tank should be connected directly with the well, so that 3 8 - Wns =) a an os tae FO Zo oe aS) Skis og as 33 ao ae _ 20 oa £3 og = 5 oS 33 Pa -oO ae os gn an 2 26 fei peace) z ns “Zo & ome LO 5 ii afar au s nL < S Cement. floor Exterior shown in Fig. 100. ry barn. tary dair system of ventilation sani A Fia. 99. 163 FOT CEOGT ‘LE ‘ON ‘omNyNoUSy Jo prvog oyvqg susuvy Jo y10d937) UMOYS OMA, “qYyStu uo apqeys-Moo “gjop UO UoTQIod UT sopgy “UNG Amrep duotpo Apoatyeavduioo ‘you W—'OOT ‘OMT 165 gare? = y ix i i a ll. I 101 A Jean well graded ard cov ered with slx inches of cinders. (Bul. 9 1 I ) IG. . Cc. ’ ’ 99T CUT ‘26 "IM) *‘oyBNUINDD¥ 0} pao st omnuUT oy) YorA ut pavd popwsBun Uy—ZOT “OTT FARM SEPARATORS. 167 the water can be pumped directly to the tank holding the milk and cream. From this place the water can be run out into the stock-tank. This arrangement allows the milk to be kept at the lowest possible temperature. It is Just as essential to cool the milk during the winter as it is during the summer. By pumping water through this tank practically all the time, the water in the tank will be kept from freezing. It is well to keep the surface of the water higher A Fic. 103.—The average weight of dirt which falls from muddy udders dur- ing milking is ninety times as great as that which falls from the same udder after washing, and when udders are slightly soiled it is twenty- two times as great. (Bul. 84, Il.) than the surface of the milk in the can. This will prevent the milk from freezing so easily. If the cold is too severe, a tank- heater can easily be secured which will moderate the tem- perature a trifle. Disposition of the Cream.—There are two ways of disposing of cream on the farm: (1) selling it to creameries or other parties, and (2) making it into butter on the farm. The former method is usually the most advantageous. Creameries, as a rule, are better equipped to control the quality of butter.. The price per pound of butter-fat is usually about 2 cents below “New York Extras.” A few of the best co-operative cream- eries are able to pay more than that. eee RI Ol} 9B SUBI-WITAID puv -YTI— FOL “PLT SOL CH {c6 Hq) “uONTAS ATA] cos NROOR ETRY re FARM SEPARATORS. 169 Shipping of Cream.—If cream is sent or shipped to cream- eries and central plants, it is essential that it be delivered as frequently as possible, and that it be delivered in cans which will help keep it in good condition. If cream is to be shipped any great distance and be exposed to the sun, it is advisable to use special jacketed cans, which retard the transmission of heat. It is a good plan to cover the cans with a wet sack or cloth during the summer, and the use of a dry sack on Fie. 105.—The Buhl milk and cream can. Fia. 106.—A barrel churn. the outside in the winter often prevents the cream from freezing. Making Butteron the Farm.—If cream is kept in good condition and proper skill is applied, the best of butter can be made on the farm. Theoretically, better butter can be made on the farm than at the creamery, because all conditions can be controlled better. This is not so in creameries. One can of bad cream mixed with a quantity of good cream is likely to contaminate and injure the whole lot. The cream which is to be made into butter on the farm should be ripened, or soured, properly before it is churned. In creameries, starters 170 BUTTER-MAKING. are used to set up a quick and desirable fermentation in the cream. Conditions are usually such on the farm that it is not ——) OF) Fic. 108.—Sanitary glass milk- bottle and cap for same. Fic. 107—The Davis swing-churn. convenient and practical to use a starter. In the summer the cream can be lifted out of the cold water the morning previous Fic. 109.—Skinner butter-worker. to churning, and it will sour during the day. In the evening, or when it has soured, it can be set back into the water to cool. “IOPBIVSG UIBAIZ) *OD JO4SAATVTT [EUOI}BUIIIUT JO SMATA [BUOIJOIG J-] auly UO [MOq JO UOTJDaS-SssOIy [AO JO MATA [BUOTIIG SAL ee 3Noz wi) ue 13 10 MTIW WINS 4311Nn0 wv3a4o FARM SEPARATORS. 171 The next morning it is ready for churning. In the winter the cream can be soured by warming it up or keeping it in a warm place. If some good sour milk is on hand, it might be added, and the cream will sour much quicker. It is very essential that the cream can be cooled to a low temperature (50° I’.) and left Fig. 111.—The Cherry jacketed cream can. | i l Fic. 110.—Milk or cream can Fig. 112.—The Jersey can-br with agitator. ‘ush. at this temperature for at least two hours before it is churned; otherwise the butter is likely to be greasy and salvy. Color and salt to suit the market and season. About three-fourths to one ounce of salt to one pound of butter usually gives good results. If a local trade can be secured, it is not necessary to pack it into tubs. Earthen jars are good to keep butter in. If no 172 BUTTER-MAKING. local trade can be secured, and it is essential to ship the butter, 20- or 30-pound tubs should be used. If a good quality and constant supply of butter can be secured throughout the whole year, it is an easy matter to find an excellent market for butter at hotels or good restaurants. (For a more detailed discus- sion of butter-making, see Chaps. XVI and XVII.) Putting up butter in prints and wrapping them in parchment paper which bears the maker’s name usually increases its value. CHAPTER XIII. PASTEURIZATION. Definition.—The word pasteurization has its derivation from Pasteur, a French scientist. Pasteurization consists in heat- ing milk somewhere between 140° F. and 212° F. This kills practically all germs in a vegetative state. Since most of them are in a vegetative condition, the process kills almost all the organisms. The heating is followed by rapid cooling. ‘‘Sterili- zation” is a word which is some times used incorrectly in con- nection with pasteurization. Sterilization means that milk or any other substance has been heated so often or to such a high temperature as to entirely destroy every living micro-organism present. In order to get a substance thoroughly sterilized without heating under pressure, it is essential that it be heated about thirty minutes on each of three or more successive days. Pasteurization in the dairy industry was introduced by Pro- fessor Storch of the Royal Experiment Station, Copenhagen, Denmark. Methods of Pasteurization.— (1) Intermittent. (2) Continuous. 1. Intermittent pasteurization is usually accomplished in vats or cans. It is used nearly exclusively when pasteurization is practiced on a small scale, such as preparation of starters in creameries, pasteurizing cream and milk on the farm, ete. Intermittent pasteurization is as efficient, and undoubtedly more so, than the continuous method. The substance pasteurized is usually exposed to the high temperature a longer time than it would be by the intermittent system. In the continuous 173 174 BUTTER-MAKING. method of pasteurization the substance pasteurized is exposed only to a sudden temporary heat. The intermittent process of pasteurization tends to drive off more of the undesirable taints present in the milk or cream. This is especially true when stirred occasionally. If heated too long the cooked flavor is likely to be more pronounced than when the intermittent system is used. If exposed very long Back Pressure Valve Skim Milk Inlet — =—= 3 Ai Skim Milk Tank i! | am UN, Exhaust Steam Fic. 115.—Scheme for pasteurizing skim-milk by the use of exhaust-steam direct. (Creamery Journal, by W. P. McConnell, Minn.) to the high temperature and stirred excessively during the intermittent pasteurization, the butter-fat tends to melt and run together, and show itself on the top of the cream in the form of an oily layer. 2. The continuous method of pasteurization is more practical for large amounts of milk or cream. It is used almost without exception in pasteurizing cream, whole milk, and skim-milk at creameries. Neither one of the two systems destroys spores. The. intermittent system is the most effective because botb PASTEURIZATION. 175 time and temperature are under control. Various pasteuriz- ing machines are in use, and it is not within the province of this work to recommend any machine. A few words in regard to the principles which affect proper pasteurization will serve a better purpose. SELECTION OF PASTEURIZERS. Improper pasteurization is worse than none at all. If pasteurization is done at all, it is essential that it be properly accomplished. There are two things to be sought when purchasing a pas- teurizer; viz., (1) durability and capacity, and (2) economic efficiency. 1, Durability and Capacity—The structure of most pas- teurizing machines is simple and substantial. They do not wear out like a complex piece of machinery. It is essential that the machine be strongly made. Heating-walls and other portions should be made heavy enough to be consistent with its use, and of a substance which will conduct heat rapidly. Nearly all the types of pasteurizers are made in different sizes to suit the demands. 2. Economic Efficiency.—Obtaining efficient pasteurization economically is the most important question. It is important in this connection because it depends upon so many conditions which the operator has under control. The degree of con- ductivity of heating-surface during operation, may in one sense include most of the essential factors which affect pasteurization. This in turn depends upon a number of conditions which are as follows: (1) Kind of material from which the heating-surface is manufactured. (2) Degree of adhesiveness of milk or cream on heating- surface. (3) Thickness of layer of condensed steam, on steam side of heating-surface. (4) Difference in temperature on each side of heating-surface. 176 BUTTER-MAKING. (5) Proper utilization of steam turned into the pasteurizer. (1) Heating-surface—It is a well known fact that some metals will conduct heat better than others. The relative heat conductivity of the two substances used chiefly for pasteurizers, viz., copper and tin, is .918 and .145 respectively. This means that copper will conduct heat nearly seven times faster than tin of the same thickness. = —— ne ir Fig. 116.—The Reid pasteurizer. In connection with this it should be mentioned that stability and durability of the substance must also be taken into con- sideration. A heating-surface made from copper may be nearly seven times as thick as that made from tin, and still transmit as much heat as the tin surface. From this it can be seen that a heating wall made from copper can be increased slightly in thickness, and thus aid in stability, without affecting the degree of heat conductivity of the wall very much. The heating- surface must be strong enough to withstand a slight steam pres- sure, otherwise the heating wall is likely to collapse or cave in in case of slight variation in the steam pressure. It is not PASTEURIZATION. 177 an uncommon occurrence to have the heating wall of a pasteur- izer burst. This could be prevented by connecting a safety, or pressure, valve, to the pasteurizer. (2) Degree of Adhesiveness.— Roughness, due to either defects in the metal itself, or to milk or cream being burned on the heating-surface, is a serious defect. Such a condition Fic. 117.—The Simplex regenerative pasteurizer (apart). causes particles of milk or cream to move very slowly over the heating-surface; it tends to roll in much the same way as drops of liquids do when caused to flow over a slanting dry rough surface. As a consequence more and more casein will adhere. The thicker the layer of foreign matter is on the heating-surface, the greater the difficulty in getting the greatest efficiency from the pasteurizer. It is important that the milk or cream be forced over the heating-surface with greater rapidity than could result from its own gravity. On heaters or pasteurizers, where milk flows 178 BUTTER-MAKING. over the heating-surface only by force of its own gravity, a heavy layer of curd usually adheres. This is due to the fact that certain portions of the milk are exposed to the excessive heating too long, while if caused to move rapidly it does not remain in contact with one portion of the heating-surface long enough to cause it to adhere to so great an extent. Fic. 118.—The Simplex regenerative pasteurizer (assembled). The condition of the milk or cream has some influence upon the degree of adhesiveness of curd on the heating-surface. Sour and coagulated milk adheres or burns on to a greater extent than does milk or cream in good condition. This is evidently due to the lesser fluidity of the sour milk, and, as a consequence, it does not move over the heating-surface so: rapidly, and therefore burns on. Milk which contains a great deal of air or scum also adheres to the heating-surface much PASTEURIZATION. 179 more readily than milk containing less air. If pumps are used for pumping the milk, it is well to admit as little air into the milk as possible. This can be accomplished by keeping plenty of milk in the tank which feeds the pump, or by having a float which will close the inlet to the pasteurizer as soon as the tank is emptied. If the speed of the agitator in the pasteurizer is great enough, the scum is forced towards the center. For | | a | a Ih | f ‘ic BV ENSEN a te Fig. 119.—The Jensen pasteurizer. some time it was thought that only the best sweet milk could be pasteurized by the intermittent process of pasteurization. It is well known that when a sample of milk reaches a certain degree of acidity it coagulates upon heating. It was thought that by the continuous method of pasteurization this would interfere with getting proper results. Experiment, however, shows that the coagulated sour cream and milk can be suc- cessfully pasteurized, but it is still a fact that the better con- dition the milk or cream is in, the easier it can be pasteurized 180 BUTTER-MAKING. and the better the results are. If pasteurization is not prop- erly conducted, often the sour milk and cream coagulate and get very lumpy. This takes place chiefly when pasteurization ‘s attempted at a comparatively low temperature, at a slow rate of speed of the agitator in the pasteurizer, and when there is about from .38% to .4% acidity in the cream or milk. Sour thin cream—less than 28% fat—does not pasteurize successfully. In case there is any danger of sliminess taking place during pasteurization, the heat should be applied as quickly as possible. Only a thin layer of cream should be exposed to the ® heating-surface at one time. Flashy, quick heat tends to prevent this slimy condition. The speed of the stirrer should be increased, if possible, when such cream is being pasteur- ized. ‘4 By greasing the inside of Ls ae > the pasteurizer, or the heat- Fig. 120.—The Miller pasteurizer. | Ing-surface, a trifle previous to pasteurization, the burning- on can be prevented in part. The casein that adheres can be more easily removed than if no grease were used. (3) Thickness of Layer of Condensed Steam.—At first glance one might come to the conclusion that the small amount of steam which is constantly being condensed upon and adhering to the steam side of the heating-surface is not sufficient to cause any difference in the efficiency of the pasteurizer. Ex- periments conducted by Dr. Storch of the Royal Experiment Station, Copenhagen, Denmark, show that this condensed steam greatly resists the transmittance of heat. The comparative heat conductivity of water and copper is .0016 and .9 respec- tively, as found by Dr. Storch. It will thus be seen that copper is 600 times as good a conductor of heat as water is. This would mean that a quiet layer of water 3 millimeters in thickness PASTEURIZATION. 181 would have the same resistance to heat as a layer of copper 2 meters in thickness. Consequently a very thin layer of water or condensed steam on the sides of the heating-wall would greatly interfere with the economic efficiency of a pasteurizer. In order to overcome this difficulty drip-rings were circled round the drum of the pasteurizer at intervals on the steam side of the heating-surface. The first rings put around the pasteurizer were narrow smooth bands. These did not give entire satisfac- tion, as the condensed water from the top rings would drip on the edge of the lower ones, and cause the water to splatter over the side of the heating-wall. Another kind of ring was then in- vented, which was thin, nar- row, and saw- teeth-like in & shape. These © rings were fast- ened to the heating-wall at proper _ inter- vals at an angle of 45°. The rings were so arranged that the drops of condensed water escaping from the end of each saw tooth would fall in the hollow between the teeth in the lower rings and thus prevent any splattering of the water against the heating- wall. These contrivances greatly increased the efficiency—as high as 48°%,—and the capacity of the pasteurizer experimented upon. (4) Difference in Temperature on Each Side of the Heating- surjace.—The difference in the temperature on each side of the heating-surface has a great effect upon the rapidity with which the heat passes through the wall. The lower the temperature is on the milk side the more rapidly does the heat pass through; and the higher the temperature of the milk is, the pressure on the steam side being the same, the more slowly the heat passes through the heating-wall. This would at first lead us to be- The Farrington pasteurizer. 182 BUTTER-MAKING. lieve that the last few degrees the milk is being heated are the most expensive; but if the steam is properly guarded from being condensed, or wasted, it does not cost any more to heat the milk the last few degrees than it does to heat the first degrees. While the temperature on the milk side is low, much more steam is consumed, and it is also used more rapidly. During the last heating of the milk or cream less steam is being con- densed and the condensing proceeds more slowly. When the temperature on the steam side is 220° F. and on the milk side is 40° F. during the same time, twice as much heat will pass through the heating wall as if the temperature of the milk side were 130° F. In the first case the difference in temperature on both sides would be: 220—40=180° F. In the second instance it would be: 220—130=90°. F. (5) Proper Utilization of Steam Turned into the Pasteurizer. —The cost of pasteurization will evidently vary under different conditions and with different kinds of pasteurizers. In order to reduce the cost of pasteurization to the minimum, it is essential that all steam turned into the pasteurizer be properly utilized. The pasteurizer, as well as the steam-pipes, should be properly insulated in order to prevent unnecessary conden- sation of steam. According to experiments carried on by Dr. Storch, all steam contains more or less air. By making a device on the pasteurizer for the escape of this air better results were obtained. By the use of such a vent it was made possible to heat 1890 pounds of water from 52° F. to 185° F., while without this air device, and with the same amount of heat, only 1467 pounds of water were heated. That is, by this device he made a gain of 30% in the heating efficiency of the pasteurizer. The contrivance used was simply a pipe attached to the bottom of the pasteurizer and extending down below the pasteurizer about 2 feet, then turned or bent, and brought up vertically a few inches above the bottom of the pasteurizer. The mouth of the pipe was then turned over. This pipe accomplishes two purposes. It removes condensed water from the pasteurizer, and also the accumulated air. It PASTEURIZATION., 183 is also essential that the pasteurizer should not leak. All the steam turned into the pasteurizer should be condensed before it is allowed to escape. The Cost of Pasteurization.—Dr. Storch in his 43rd report of the Royal Agricultural Experiment Station, at Copenhagen, Denmark, reports that it requires 80 pounds of steam to heat 1000 Danish pounds of milk from 40° C. to 85° C. This would be equivalent under American conditions to about 90 pounds of steam to pasteurize 1000 pounds of milk from 90° F. to 185° F. According to good authority it takes 1 pound of lump coal to produce 6 pounds of steam. Calculating from this, it will take 15 pounds of coal to produce 90 pounds of steam. If coal costs $4.00 per ton, the cost of 15 pounds of coal would be 8 cents. If the milk tests 3.6% fat, and calculated on one-sixth overrun, the 1000 pounds of milk would produce about 42 pounds of butter. The cost of pasteurizing the milk producing 42 pounds of butter is then 3 cents, and the cost of pasteurization per pound of butter would be .07 of a cent. Taking into consideration the cost of cooling, and counting on about .03 of a cent for leaks involved during the process, the cost of pasteurizing per pound of butter would be about 1 of a cent. As arule, the major portion of the cooling is done with water, which at most creameries costs little or nothing. For this reason the cost of cooling has been omitted. Advancement of Pasteurization—During the last few years pasteurization has gained favor with the American creamery operators. It has been thoroughly demonstrated that if the best product is to be manufactured it is absolutely essential that the operator have complete control of the fermentations in the cream or milk. This control of the fermentation can best be accomplished by the process of pasteurization. Pasteurization has been gaining favor with the creamery operators owing to its own merits. The Danish Government compelled the pas- teurization of milk or cream as a safeguard against tuberculosis. It was found not only that the system was efficient in this respect, but also that it produced a more uniform product, with 184 BUTTER-MAKING. better keeping qualities. At the present time nearly all of the central plants are pasteurizing their cream to a greater or less extent. Advantages of Pasteurization—The advantages of pasteur- ization are many, but the chief ones are as follows: (1) It enables the butter-maker to produce a uniform quality of butter. If most of the germs are destroyed by pasteurization, and a pure culture added to the cream, the ferments added will be in full control. If nothing but a desir- able kind of germ is added, it follows that the product will be uniform in quality In this way practically the same results can be obtained from day to day. (2) It eliminates many of the undesirable taints in the milk. Especially is this effect noticeable during the fall, when cows are liable to eat weeds that taint the milk. No matter how well milk has been taken care of, it usually contains taints which, when pasteurized will be partially eliminated from the milk. (3) It destroys most of the germs. This is important for two reasons. It destroys most of the germs which effect the quality of the butter, and it also destroys the pathogenic germs, thus preventing the spread of diseases, such as tuber- culosis, typhoid fever, etc. (4) The butter-maker can control the fermentation in cream much more easily when pasteurization is employed. It has been demonstrated that the quality of the butter depends in large measure upon the kind of fermentation. When the fermentation in the cream is thoroughly controlled, a better quality of butter can be produced. When the milk is in first- class condition, fully as good butter can be produced without the use of pasteurization, but it does not keep so well. Milk may appear to be in good condition, and yet at the same time contain germs which are detrimental to the quality of the butter. It is at the present time a matter of dispute whether milk and cream in a really sour and poor condition is benefited PASTEURIZATION. 185 much by pasteurization. The flavor of the butter made from such pasteurized cream is usually not improved very much. However, the keeping quality of butter made from poor cream pasteurized is usually better than if no pasteurization had been employed. If the inferior quality of cream and milk can be pasteurized, neutralized with an alkali, such as powdered chalk or bicarbonate of soda, then inoculated with a desirable species of bacteria and re-ripened, the quality of butter can be im- proved several points. But experiments carried on at the Towa Experiment Station indicate that the improvement in the quality of butter is not very permanent. Immediately after it has been made there is a very distinct improvement in the quality of the butter from such cream, sometimes as much as five points. But for some reason butter from cream that has been neutralized in such a way does not seem to keep well. Some days after its manufacture it begins to lose decidedly in flavor and to assume a very rank condition. For this reason this method of treating poor cream has not been generally advocated. The deterioration that takes place in such butter after standing seems to be due to chemical changes rather than to biological changes. The butter referred to was kept in a refrigerator at a temperature of about 50° F.; if the rancid flavors were due to the growth of micro-organisms, they should not reveal themselves in so short a time. (5) Pasteurization increases the keeping quality of butter. This is one of the greatest advantages of employing pasteuriza- tion in butter-making. The advantage of keeping butter from the time of large supply and small prices to the time of small supply and higher prices, makes pasteurization in butter-making of vital importance in improving the keeping qualities of butter. Butter made from good pasteurized cream and washed in pas- teurized water will keep about twice as long as butter made from the same kind of cream not pasteurized and washed in unpasteurized water. (6) If milk is pasteurized previous to skimming, closer skimming can be obtained than if the milk were heated to a 186 BUTTER-MAKING. comparatively low temperature. The reason for this has been previously explained. Disadvantages of Pasteurization.—The cost and additional trouble involved in pasteurizing are undoubtedly the chief disadvantages that could be brought up against pasteurization. As was calculated above, the cost of pasteurization, after the pasteurizer has once been purchased, is only .1 of a cent per pound of butter. This cost would be reduced considerably if the cream only were pasteurized, and increased if the cream and skim-milk were pasteurized in separate machines. The Sere | eee ne [Seek wreck | aed eee | wecke| eck | mock: | 2eee [seen cack | HR, | JA [Score 96 96 94 94 92 aa ae 92 50 : ‘ Po este, 90 ea] | PE TS 88 8G | Neel = 86 84 N&, Re 84 82 K A. [ee ft) aN ‘so 78 a 78 76 76 a — tos Fic. 121—Comparison of deterioration of butter made from pasteurized cream and wash-water to that made from unpasteurized cream and water, illustrated graphically. (Bul. 71, Iowa.) initial cost of the pasteurizer is the great mountain to over- come in the introduction of pasteurization in creameries. When pasteurization is employed in butter-making, it is absolutely essential that the greatest degree of skill and in- telligence be applied. If care is not taken pasteurization is likely to produce a poorer quality of buttcr than is the case when no pasteurization is employed. Especially is this true when sour or abnormal cream and milk are being pasteurized, and little or no starter is used. CHAPTER XIV. CREAM-RIPENING. Definition.— By cream-ripening we mean the treatment cream receives from the time it is put into the ripening-vat until it is put into the churn; and also the chemical, biological, and physical changes cream undergoes during the same time. Oxssects oF RIPENING. (x) To Produce Flavor and Aroma.—The chief object of cream-ripening is to secure the desirable and delicate flavor and aroma which are so characteristic of good butter. These flavoring substances, so far as known, can only be produced by a process of fermentation. It is a well known fact that the best flavor in butter is obtained when the cream assumes a clean, pure, acid taste during the ripening. For this reason, it is essential to have the acid-producing germs predominate during the cream-ripening; all other germs should if possible be excluded or suppressed. It has not yet been proved that any one particular species of bacteria is responsible for the production of the flavors, but it is agreed by all that the flavoring substances developed during the ripening of cream are decomposition products of bacterial growth, and that the types producing the lactic acid are the most desirable ones to have present. There are a great many bacteria in milk and cream which will produce acid. Over one hundred species have been studied and described. There seems, however, to be a comparatively few of those which produce the best results. 187 188 BUTTER-MAKING. It seems that during cream-ripening the development of acid, aroma, and flavor go hand in hand. This does not neces- sarily indicate that they are produced by the same cause. It is possible that the flavor and aroma substances are chemically produced from the various by-products of the germs. Bacteriologists do not agree as to what species of bacteria is responsible for the high quality of flavor and aroma of butter. Conn * claims that the germs which act upon the nitrogenous Beeb, Fic. 122-—The McAreavy cream- Fig. 123.—The Miller cream-ripening ripening vat. vat. matter of milk are associated with the lactic-acid-producing bacteria in the production of desirable butter flavors. Weig- man asserts that the best results are obtained when a variety of species work together in the cream. He has isolated a single species of germ which produced alcohol and lactic acid as by-products, and which, according to experimental evidence deduced by him, is capable of producing the delicate butter flavors. Freudenrich has also studied a species of germ which produced alcohol and lactic acid as by-products, and was able to produce the characteristic butter flavors. Eckles has studied this question of flavor production during cream-ripening. He comes to the conclusion that the flavor and aroma substances * Storr Station, Conn. CREAM RIPENING. 189 developed during cream-ripening may be produced by a variety of acid-producing bacteria. He asserts that of the species tried the most common milk-souring organism (Bacterium lac- tarii) gave the most satisfactory results as a culture for ripen- ing cream. Storch, who has perhaps studied this question more than any one else, maintains that the germs producing lactic acid are essential to good cream-ripening, and that the flavor and aroma products are the results of the joint action of a great many species of lactic-acid-producing germs. Tiemann * finds that an addition of a small amount of hydrochloric acid to the cream does not produce the characteristic flavor, and in- Fig. 124.—The Wizard cream-ripening vat. dicates that the process of fermentation is necessary to get the proper flavors. Dean, of the Ontario Agricultural College, has recently reported that the flavoring substances can be developed in the starter, then added to the cream. The re- sulting butter has as good or a trifle better flavor than that which undergoes a process of fermentation by ripening in the usual way. From the investigations quoted above it will be seen that there is some doubt yet as to the specific origin of the flavor and aroma substances developed during cream-ripening. It is also not known for certain just what those flavoring sub- * Milch-Zeitung, Vol. 13, p. 701. 190 BUTTER-MAKING. stances are. They are evidently volatile, ether-like compounds, which are produced by bacterial growth during the ripening process. Few years ago it was thought that these flavoring substances were due entirely to the oxidation process, and that in order to get these flavors in butter it was necessary to expose the cream to pure air during the ripening. It has now been proved that air might be excluded from the cream-vat, and still good results be obtained. This does not, however, demonstrate that oxygen is not essential for the best results in cream-ripening. All cream contains more or less oxygen in solution. It has been thought that the oxygen that cream holds in solution may favor the growth of the desirable germs in cream, and that as soon as this has been utilized, conditions may become unfavorable for the desirable germs and favorable for the undesirable germs. Practically, all the investigators agree that the flavor and aroma substances which are characteristic of butter and which are developed in ripening cream, are due to bacterial growth, and that the germs producing lactic acid are the most desirable ones. We quote the following instances to show what effect some species of bacteria may have upon the quality of butter, when present in the cream: Number. Species Used for Starter. sear ent Pisyon, Peete 1 Bacterium lactarti...........- 39 $.20 2 Bacillus subtillis............ 31 14 These two samples of butter were made from the same kind of cream which was pasteurized and inoculated with starters from the different germs as indicated in the table.* The butter ripened with Bacillus subtillis sold for 6 cents per pound less than the other, a difference of nearly one-third in value, due to the character of fermentation in the cream during ripening. Therefore in developing the proper fiavors in * Bul. 40, Iowa Experiment Station. CREAM-RIPENING. 191 butter, it is very essential that the undesirable germs be ex- cluded or suppressed and that the conditions for the develop- ment of the desirable typical acid ferments in the cream be made as favorable as possible. The undesirable ferments may, as a whole, be said to be those which act upon the nitrogenous matter, or those which cause ordinary decay. They very likely come from filth in the barn, milking utensils, unclean milkers, Fig. 125.—The new Jensen cream-ripening vat. (Peerless.) and unclean and dusty barns. Abnormal fermentations of cream, such as ropy, bitter, chromogenic fermentations, etc., are of course undesirable ferments. For kinds and classifica- tion of germs in milk, see Chapter IV on Bacteria, and Chapter V on Abnormal Milk. (2) To Increase Churnability of Cream.—Cream-ripening is not essential in order to complete the churning process, but ripened cream will churn more easily and more completely than unripened cream, under the same conditions. This is due to a 192 BUTTER-MAKING. lessening viscosity of the cream. The ripening process causes the cream to become thicker but less viscous. Undoubtedly the acid developed during the ripening process tends to cut the membrane supposed to surround the fat-globules. The reduced viscosity of the cream renders it easier for the globules to move and unite in the serum when exposed to agitation in the churn. It is possible to churn ripened cream in a thinner state and at a lower temperature than unripened cream. Cream which has been ripened to a normal degree of acidity, also allows of a more complete churning than unripened cream. Fic. 126—The Boyd cream-ripening vat. If cream is properly ripened, and churned at a medium low temperature, it is possible to churn so that the buttermilk con- tains only about .1% of fat by the Babcock test; while if sweet cream is being churned under the same conditions, the butter- milk will contain more than this. This is undoubtedly due to the fact that in sweet cream the viscosity is so great that it prevents the minute fat-globules from uniting when agitated in the churn, while in sour milk the viscosity has been largely removed. Sour cream is thicker than ripe cream, but less viscous. This facilitates the coalescence of the fat-globules when exposed to agitation. (3) To Increase the Keeping Quality of Butter.—It has been demonstrated by several investigators that the keeping quality of butter depends chiefly upon the number and kinds of germs present in the butter after its manufacture. In order, there- CREAM-RIPENING. 193 fore, to produce butter with good keeping qualities it becomes essential to exclude or suppress all germs which deteriorate butter. It is not of so great importance to exclude germs which do not injure the keeping quality of butter. The germs that produce lactic acid do not cause direct deterioration of butter. This has been demonstrated by Jensen.* When cream has been properly ripened, it is practically a | 5 Gal : | Fie. 127.—The old Jensen cream-ripening vat. pure culture of lactic-acid-producing germs, while sweet un- pasteurized cream contains a bacterial flora, consisting of a great many types of desirable and undesirable germs. It should be mentioned in connection with this, that it is only properly ripened cream that contains with any certainty, a preponderance of germs producing lactic acid. If the cream is over-ripe, the undesirable bacteria may also gain the ascen- * Landwirtschaftliches Jahrbuch der Schweiz. 194 BUTTER-MAKING. dency of the desirable. When such overripened cream is churned, these undesirable germs are transmitted to the butter, and cause deterioration. If the butter is churned from properly ripened cream, and at the proper ripening stage, and the butter washed in purified water, very few undesirable germs are trans- mitted to the butter, and, as a consequence, it keeps better. Ripening Temperature of Cream.—In practice, the ripening temperature of cream varies within wide limits. Some makers prefer to ripen cream at a temperature of about 80° F., others ripen at about 70° F., and still others prefer to ripen at a tem- perature between 60° and 70° F. Undoubtedly, the conditions. in the creamery will to some extent govern the ripening tem-- perature. Up to a certain limit the higher the temperature, the quicker the ripening process. In some instances, it is. desirable to ripen and cool cream in a few hours, and then churn the same day. Under such conditions a comparatively high ripening temperature is undoubtedly preferable, as the cream will sour more quickly at such a temperature. Un- doubtedly good butter can be made at any of the temperatures mentioned above, but when we are to decide which temperature is the best, we are, through experimental evidence, forced to come to the conclusion that a ripening temperature between 60° and 70° F. gives the best results. When cream is ripened at a high temperature it needs to be cooled very little previous to ripening. Milk is usually sepa- rated at a little above 80° F., and if the starter is added imme- diately after separation, it will ripen in a very short time. If ripened at a lower temperature, a longer time will be re- quired to develop the same amount of acid, and hence with a prolonged ripening period more attention is necessary. The Danish butter-makers ripen their cream at a comparatively low temperature, usually between 60° and 65° F., and obtain the best results. The germs producing lactic acid grow within a wide range of temperature; viz.: from about 50° to 100° F. The extreme temperatures are not favorable to the greatest possible growth. CREAM-RIPENING. 195 The optimum temperature, or the temperature at which they grow best is, according to Russell, from 90° to 95° F. At this temperature the germs which cause undesirable results also grow most rapidly in cream. Cream contains germs both of the desiarble and the undesirable type. At a comparatively low temperature (between 60° and 70° F.) the greatest relative growth of the desirable germs is produced. Bacteriologists also Fic. 128.—Cream-ripening room in the Model Creamery at the World’s Exposition, St. Louis, Mo. tell us that the casein ferments as a rule thrive better at a lower temperature than do the lactic-acid ferments at the same temperature. This, keeping in mind that better results are obtained by ripening at lower temperatures (60° to 70° F.), seems to indicate that the flavoring substances are not formed entirely by the action of certain germs producing lactic acid, but that the flavoring substances are probably due to the joint action of several species. Lactic acid itself does not have 196 BUTTER-MAKING. the desired characteristic flavor of good butter, yet we know that these flavoring substances are direct products, or accompani- ments, of the development of lactic acid. Cream ripened at a low temperature does not sour very rapidly; the germs do not grow at a very rapid rate. The desired degree of acidity is approached very slowly, and as a re- sult the fermentation may be checked almost at once when the desired degree of acidity has been reached, and the chance for getting overripened cream is reduced to its minimum. If the cream is ripened at a high temperature, there is greater danger of getting overripened cream. Extreme and rapid changes of temperature should be avoided as much as possible. The more uniform the temperature can be kept, if suitable for proper ripening, the better the results. Accordingly, the ripening-vats used in this country are practi- cally all jacketed, which permits the operator to regulate at will the temperature of the water in the jacket surrounding the cream. Amount of Starter to Add to Cream.—The amount of starter to add to cream will vary according to the temperature of the cream, and to the length of time required for ripening. If cream is to be ripened quickly, then a large starter should be added. Good results can be obtained by adding starter to the extent of 50% of the cream to be ripened. This much, however, is usually not satisfactory, as it so reduces the thick- ness of the cream as to render it more difficult to churn. It increases the amount of serum which will form the buttermilk when churned. The more buttermilk, the greater will be the loss of fat in churning. On this account it is desirable not to add any more starter than will give cream a proper thickness (from 30% to 35% fat) and at the same time supply enough desirable germs to gain the upper hand of, and to suppress the undesirable germs already present. It is important to skim the cream thick enough to permit the use of an amount of starter equal to from 8% to 20% of the cream to be ripened. This, under average conditions, will CREAM-RIPENING. 197 produce desirable results, providing the starter is of the proper kind. A poor starter is worse than none at all. It is a good plan to pour the starter into the ripening-vat before the cream is separated. Some also practice skimming a heavy cream and then add some good morning milk to it. Before the starter is added all precautions possible should be taken in order to prevent the entrance of undesirable germs into the cream. The top layer of the starter should be skimmed off; and the very bottom portion of the starter should not be emptied into the cream-vat either, as it usually contains some of the sediments from the milk. It is essential that the starter should be thoroughly stirred previous to adding it to the cream, otherwise lumps of curd are likely to trouble during the re- mainder of the process of manufacture. The curd, if not properly emulsified previous to adding it to the cream, is likely to show itself in the butter in the form of white specks. This stirring of the starter can be brought about most satisfactorily by pouring it back and forth from one can into another, until the body of the starter assumes a uniform, not lumpy, con- sistency. The cans used for this purpose must be carefully cleaned and scalded previous to using them. Dippers and stirrers of any kind should always be thoroughly sterilized previous to using them in starters. The stirrer or dipper used should have solid handles. This makes cleaning easier. Stirring of Cream During Ripening.—As soon as the starter has been brought into a proper condition it is added to the cream. If necessary it should be strained before adding. The cream should then be thoroughly stirred. If cream is not thoroughly mixed with the starter, the ripening will not be uni- form. If allowed to stand quietly, the cream soon separates into two distinct layers. The fat, by reason of its being lighter than the rest of the constituents, soon forces its way to the surface, and incorporates with it a considerable amount of casein. But the -bottom layer will be similar to skim-milk; for, being better mixed with the starter, the lactic-acid fer- mentation proceeds more rapidly in this milky or bottom layer, 198 BUTTER-MAKING. and thus prevents the fat which is at the surface from coming in direct contact with the flavoring substances formed at the bottom. If the surface layer of fat and casein were exposed to favorable conditions, the point might be made that the sur- face exposure is more desirable than if the fat were in a state of perfect emulsion with the rest of the constituents of cream. But such is not the case. The layer of fat and curdled casein, when allowed to form at the surface, is likely to be contami- nated with putrefactive organisms. Especially is this so if the cream is allowed to stand in such a condition very long in a warm ill-ventilated room. If the constituents of cream are kept well mixed by stirring, the lactic acid checks the development of putrefactive germs, which may accumulate at the surface; the cream is ripened more evenly, and the flavor- ing substances have the best facilities of coming in contact with and being absorbed by the fat. The authors have noticed that high-scoring contest butter is usually made from cream which has been stirred judiciously at intervals. The most notable prize winners have stayed up with their cream all night, or part of the night, to watch the ripening process, and to stir the cream occasionally. It would not be practical to advise this method, but cream should re- ceive a judicious amount of stirring at intervals during the day, and if it is allowed to stand over night, it should be stirred the last thing in the evening before retiring. NaTuRAL AND ARTIFICIAL RIPENING. Cream-ripening as a whole, as practiced to-day, may be divided into two groups: viz., (1) Natural, and (2) Artificial. Natural.—Natural cream-ripening consists in letting the raw cream stand at a certain temperature until it is sour, then cooling it to the churning temperature. This method used to be practiced nearly altogether, but now experimental and practical evidence prove that this is not the method by which the best butter can be produced. Natural ripening may, or CREAM-RIPENING. 199 may not, produce good results. It has been termed by some “chance ripening.” At certain seasons of the year conditions are favorable for natural ripening, while at other seasons con- ditions are very unfavorable. It was stated hefore that putre- factive organisms, or those germs causing ordinary decay, are undesirable species of bacteria to have present in the cream. During the late spring and early summer months, when the cows are first put on pasture, the conditions are favorable for the preponderance of the desirable germs; during the winter, when necessarily the cows and the milk are subject to stable conditions to a greater extent, the conditions are favorable for the ascendency of the undesirable germs. Eckles has found that during the winter about three-fourths of the bacteria in milk consists of these undesirable germs. If these are present in the milk, a proportionate part will be transferred to the cream. When such cream is allowed to ripen or ferment in a natural way, the undesirable germs are likely to gain the ascen- dency. As the conditions which govern the degree of con- tamination of the milk and cream vary during the different days of the different months and different seasons of the year, this natural ripening is not to be depended on for obtaining a good uniform quality of butter, even though at times good results may he obtained from natural ripening. A maker who wishes to make a high, uniform grade of butter should not depend upon natural cream-ripening. Artificial Ripening.—- By artificial ripening we mean (1) ripening of raw cream to which sufficient starter has been added to control the kind of fermentation; (2) ripening of cream in which the germs have been destroyed by pasteurization, and to which a starter has been added in order to introduce the desirable ferments. (1) Either of these methods is preferable to natural cream- ripening. The first method has been the most common in the past, but the latter method promises to give results which will warrant every butter-maker in adopting it as a permanent method in butter-making. If cream has been handled under 200 BUTTER-MAKING. conditions which are favorable for the introduction of desirable germs, and is otherwise in good condition, the best results can be obtained by ripening such cream without pasteurizing it. It is asserted that when all conditions are ideal,—the starter good, and the cream good,—then a higher flavored butter can be produced by this method than if the cream were pasteurized ; but the keeping quality of the butter is not so good as that produced from pasteurized cream. The same objection that was made to natural ripening can be made to the artificial ripening of raw cream. If the butter-maker at the creamery has full control of all the conditions governing the quality of butter, and if the milk is received at the creamery in an ideal condition, then this method of ripening is commendable. But at creameries where milk is at times delivered from one hundred or more different patrons, some of the milk is likely to come in in an unfavorable condition. The poor milk is likely to contaminate all the remainder of the cream, and objectionable fermentative products are likely to develop in the cream-vat. When this method of ripening is practiced the starter should be added to the cream as soon as possible. In fact, this rule applies to all methods of cream-ripening where a starter is used. It is preferable to add the starter to the cream-vat before the skimming is begun. In this way the lactic-acid germs in the starter get a chance to work in the cream immediately after it is skimmed, and, for this reason, are more likely to suppress the undesirable types of ferments present. 2. The second method, that of pasteurization, is without any question the ideal way of manufacturing butter. It has been advocated in a theoretical way for several years in this country, but only within recent years has this method of ripening cream been deemed sufficiently meritorious to warrant its adoption. It is, however, rapidly gaining in favor. The method consists in heating the cream on a continuous pastuerizer from 155° to 190° F. A temperature of about 180° F. is the one usually employed. It is said that a temperature of 140° to 150° F. destroys practically all the germs producing lactic CREAM-RIPENING. 201 acid. Some undesirable germs also, in a vegetative stage, are not destroyed at this temperature. For this reason cream should be heated to about 180° F. At this temperature, the germs causing tuberculosis are destroyed. It isin order to com- bat this disease that the Danish Government compels all cream to be pasteurized before it is made into butter, and also all of the skim-milk before it is returned to the farmer. The germs causing tuberculosis are destroyed at a lower temperature than this (180° F.), provided they are exposed to the temperature for some time. In creameries the intermittent method of pasteur- ization isused. In this method the time of exposure to the heat is short, and consequently a higher temperature is necessary. By heating milk to such a temperature practically all of the germs, desirable and undesirable, are destroyed with the ex- ception of those that are present in the spore form. If this cream is inoculated with the desirable germs, then theoretically and practically, good uniform results should be obtained. It was mentioned above that the spore-bearing bacteria were not destroyed by the degree of heating to which cream is ex- posed. If the cream is allowed to stand any length of time at a favorable temperature without a starter in it, these spores will develop and cause undesirable results. If pasteurized cream is allowed to ripen naturally, a very bitter flavor usually develops. In order to overcome this undesirable fermentation, it is essential that the starter should be added as soon as possible after the cream has been cooled down to the desirable ripening temperature. It should be remembered that this starter should never be added to the cream while it is still hot, as the lactic- acid-producing germs in the starter would then be destroyed. Ripening Cream When Churning is Done Once Every Other Day.—At certain seasons of the ycar the milk delivered to the creamery is not sufficient in quantity to produce enough cream so that it is worth while to churn every day. Many makers profitably utilize their time by churning only every other day. The question then comes, how may the cream be preserved in the best possible condition? Some prefer to cool the cream to 202 BUTTER-MAKING. a low temperature (50° F.) immediately after it has been skimmed or received, then allowing it to stand until the next day. The second day’s cream is then poured in with the first day’s cream, the starter added, and the ripening process com- pleted. Others prefer to add the starter to the first batch of cream immediately after it has been skimmed, then ripen it almost to the normal degree of acidity, and cool to about 50° F. The next day the new cream is skimmed into this already ripe cream, stirred thoroughly, and the ripening process com- pleted. The latter method, if done properly, has given the best satisfaction. When cream is ripened according to the method first described, undesirable fermentations are likely to gain ascendency. As has been mentioned before, the undesirable germs grow better at a lower temperature than do the bacteria producing lactic acid. When the next day’s cream is skimmed into this, the undesirable ferments may preponderate to such an extent that the desirable germs cannot overcome or suppress them during the remainder of the ripening process. According to the latter method, the first day’s cream is ripened as usual. When the next day’s cream is skimmed into this, the first lot of cream acts as a starter. The lactic acid present inhibits the growth of other undesirable species, and consequently better results are obtained by this method. This latter method of holding cream is recommended when cream is to be held for any length of time, such as over Sunday, or when the creamery is run only every other day, and the churning done once or twice per weck. If possible, and all the other conditions consistent, it is better to ripen the cream and churn it the day it is delivered than it is to hold the cream over for several days before it is churned. Butter will always keep better than cream, under any conditions. MIXING or CREAM. With the introduction of hand-separators the quality of cream received at creameries varies considerably. The ques- tion then arises, should the different quantities of cream be CREAM-RIPENING. 203 mixed, or should they be treated separately according to quality, and made up into several gradesof butter? Theoret- ically the grading of cream into two or three, or even four, grades can be argued to be correct and proper, yet in creameries where only a comparatively small amount of cream is handled, it usually does not pay to grade very much. In a very large plant where as much as 50,000 pounds of butter is made per day, there is no question that a system of grading cream pays. Several large central plants are now grading their cream into three or four grades successfully. In smaller plants, however, . it is not as a rule advisable to make more than two grades, the first grade to include all good and fair cream, and the second grade to include the very poorest. Usually in the comparatively small creamery plants, the quality of cream can be better controlled, and consequently less grading is necessary, while in a large plant the creamery manager has but little con- trol over the conditions governing the quality of the cream. The chief conditions that determine whether different qualities of cream should be mixed, might be said to depend upon: (1) The quality of the cream. (2) The kind of market for the butter. (3) The amount of hand-separator cream compared with the amount of good quality cream, usually sepa- rated from the milk at the creamery. (4) The general creamery conditions. 1. Quality of Cream.—The difficulty of grading cream is met with chiefly in comparatively small creameries where part of the intake is cream and another part milk. The cream that is separated from the milk at the factory is usually in an ex- cellent condition, while the cream delivered from hand sepa- rators, or raised by any of the gravity methods, is usually of a poor quality. If the cream delivered to the creamery is in just as good condition as that obtained from whole milk skimmed at the factory, then there is no danger in mixing the two kinds 204 BUTTER-MAKING. of cream. If it comes in a poor condition, such as hand- separator cream usually does, then the poorest cream should be ripened by itself. Some maintain that the mixing of the two kinds of cream is favorable, because, if the hand-separator cream were churned separately, it would produce butter which is very poor in quality, while, on the other hand, if the two were mixed a better quality as a whole would be obtained. This is undoubtedly true; but evidently if the quality of butter from the hand-separator cream was raised, that from the whole milk was lowered, so that the quality of butter re- ceived from both was poorer than that which would have been obtained from the whole milk if kept separate. 2. Kind of Market.—If a creamery operator is working strictly for quality, and the butter is sold on that basis, it certainly would not be a good plan to mix the poor cream with the better cream. On the other hand, if the butter is sold on the market with no attempt to establish a reputation, no further aim than to get as much as possible out of the present supply, then it might pay. By mixing the two it might be possible to raise the quality so as to bring all of it on the market at a trifle above “Creamery Extras’’; while if the cream from the whole milk were kept separate, perhaps no greater price could be obtained for the butter produced from this better cream. If the butter from the poor hand-separator cream were placed on the market by itself, evidently it would not command the same price as that made from the whole milk, or the mixed lot either. As has been stated before, the mixing of poor cream with a good quality of milk, skim-milk, or whole milk, and stirring the mixture thoroughly improves the quality of the butter in a marked degree. 3. Amount of Cream.—If only a small amount of hand- separator cream is being received, then usually it will not pay to carry it through by itself. By experience the authors have found that the best way to dispose of a comparatively small amount, providing it is not too sour, is to empty it into a receiving-vat with the milk, and stir it well, re-skim it and CREAM-RIPENING. 205 pasteurize all the cream, add a starter, and ripen in the usua way. If the cream is sour, and there is a danger of souring the remainder of the milk, or clogging the separator, it is ad- visable to add it directly to the cream-vat. The sourness of the cream is not so dangerous if the flavor is clean. If it is very unclean, and not sour, the mixing with the whole milk, the separation, and pasteurization will eliminate a great many of the undesirable flavors and check the activity of a large portion of the undesirable germs present. When the starter is again added and ripened, a good quality of butter is ob- tained. If a comparatively large amount of cream in poor condition is received, then it is advisable to retain it by itself. 4. General Creamery Conditions.—Occasionally it happens that a creamery is not properly equipped with vats, so as to enable an operator to handle two lots of cream. Where one man has to do all the work, one churning is about all he can accomplish daily, besides attending to the remainder of the work. Under such conditions it is doubtful whether it will pay to purchase additional vats and hire additional help, in order to keep poor hand-separator cream separate from the remainder, through the different steps of manufacture. Since the butter is not sold strictly on its merits, there would, as a rule, be no profit for the average small creamery to grade the cream, on account of the additional labor and apparatus re- quired. If a high quality of butter is the supreme aim of the creamery operator, then it becomes very essential that the poor cream be kept separate. EXAMINING AND TESTING CREAM FOR ACIDITY DURING RIPENING. As has been stated before, the best flavor in butter is pro- duced when cream is ripened to the proper degree of acidity. If it is ripened too much, or overripened, the butter will assume a high flavor and strong aroma, while if not ripened high enough, it will be a little flattish with less aroma. Many makers depend 206 BUTTER-MAKING. upon the taste and smell, and the appearance of the cream, to decide when the cream has been ripened to the desired degree of acidity. Makers with a great deal of experience are able to tell quite accurately by the appearance of the cream and its taste and smell when it has been properly ripened. Well-ripened cream gets an apparently granular and glistening condition. It has a pleasant, mild acid taste, and a good clean sourish aroma. As the flavor of properly ripened cream will vary somewhat according to the different degrees of richness of the cream, it is very easy to be deceived by the senses. For this reason it is advisable to use a special test with which to measure the amount of acid developed in the cream. There are two acid tests in general use now in creameries, viz., “‘Mann’s Test”? and the ‘Farrington Test.” Mann’s Test.—Mann’s test consists of measuring the acid in the cream by means of an alkali of a definite known strength. The kind of alkali used is usually a .1 normal solution of caustic potash (KOH) or soda (Na.OH). E i at ee {Or These solutions can be made up very Bleed esac o cheaply or bought from the supply- large bottle, as shown in houses. Mann’s test is based upon mea- Fig. 131 and 130. suring out 50 c.c. of cream by means of a pipette. A few drops of an indicator (phenolphthalein) is added. This indicator gives a red color in an alkaline solu- tion, and no color in an acid solution. The .1 normal alkali is poured into a burette, and the solution allowed to run into the 50 c.c. of cream and stirred thoroughly until it begins to turn pink in color. At this point it is neutral. The number of cubic centimeters of alkali required to neutralize the acid in 50 c.c. of cream indicates the number of degrees of acid. CREAM-RIPENING. 207 For instance, if it required 32 c.c. of a tenth normal alkali to neutralize the acid in 50 c.c. of cream, the acidity of the cream would be 32°. (1 c.c. of N/10 alkali = 1° Mann’s Test.) Mann’s test reading can be converted so as to express the results in percentage similar to the Farrington test. As 1 c.c. Fal ectt) et Got PT TN ok =) Fie. 130.—Arrangement Fig. 131. for keeping alkali for the Mann’s test. of the .1 nermal alkali neutralizes .009 grams of pure lactic acid, 32 c.c., as in the above case, would neutralize 32 times .009. This would give the amount of acid, calculated in terms of lactic acid, present in the 50 c.c. of cream. This product 208 BUTTER-MAKING. divided by the 50, and multiplied by 100, would give the per- centage of the acid present. Farrington Test—The same principle is involved in the Farrington test. The alkali is put up in small tablets, already containing the indicator. These tablets contain a definite amount of alkali, and are represented as retaining their strength. However, they lose their strength if they are exposed to the atmosphere. The amount of alkali embodied in each tablet is such that when five of them are taken into a graduated cylin- der, the cylinder filled up with distilled water to the 97-c.c. Fic. 132.—Apparatus for the Farrington acid test. mark, and the tablets thoroughly dissolved in water, a solution is obtained, each cubic centimeter of which represents .01 of 1%, of acid, providing 17.6 c.c. of cream is taken. The tablets can be made up of different strengths for the use of different- sized pipettes, but as the 17.6-c.c. pipette is the one which is used in the ordinary Babcock test, directions are given for the use of that pipette only. For a more detailed description of the acid tests see ‘‘ Milk Testing,” by Farrington and Woll. Amount of Acid to Develop.—The amount of acid to develop in cream depends upon the amount of fat present in the cream, and to some extent upon the market on which the butter is CREAM-RIPENING. 209 to be sold. Some markets require higher flavored butter than others. Practically all markets, especially in this country, demand butter which has a comparatively rich creamy flavor, with a nice clean butter aroma. It was found by the Iowa Experiment Station, from a large number of experiments, that cream containing 30% fat should be ripened to 37° Mann’s test, in order to get the very best results. It has also been demonstrated, that the acid is developed only in the serum portion of the cream. From this it can be seen that the more fat there is in the cream, the less serum there will be. As the acid develops only in the serum, the less acid it will be necessary to develop in rich cream in order to have a definite strength of acid in the serum portion. On the other hand, the less fat there is in the cream, the more serum there will be, and the more acid necessary compared with the whole amount of cream, in order to get the same strength of acid in the serum part. A definite relation of fat to the amount of acidity produced ean be obtained by making use of the following formula: Subtract the per cent of fat found in the cream from 100, and the remainder will be the serum. Divide this by two, and the quotient represents the number of degrees of acidity (Mann’s test) required. For instance, if we were to ripen a vat of cream containing 32% fat, the problem would stand something like the following: 100 —32=68 + 2= 34° acidity, to be developed in that partic- ular vat of cream to obtain the best results. ( 100 —fat in cream 3 = degrees of acidity required.) The above formula will give good results when normal cream is being ripened. When the cream gets abnormally thin, the result will be a little too high, and when very rich cream is ripened, the result will bea little too low. It is usually said that it is not advisable to ripen cream any higher than to .65% of acidity. 210 BUTTER-MAKING. CHEMICAL, PHYSICAL, AND BIOLOGICAL CHANGES. Physical Changes.—All the changes in cream during ripening are very complex, and the causes of them are not well under- stood. The chief cause of the ripening process, as it normally occurs, is the action of micro-organisms. As has been stated before, the germs producing lactic acid are the most numerous. These germs continue to gain the ascendency in the cream during the ripening until cream is almost a pure culture of lactic-acid-producing germs. Accompanying this growth, the sugar present in the cream is broken up into lactic acid and several other by-products which will be mentioned later. These different by-products have certain physical effects upon the body of the cream. The acid developed causes the cream to coagulate and become thick. As the ripening process is carried on the appearance of the cream changes some- what. It becomes thick, granular, and glistening in appear- ance. Undoubtedly the film of casein, or whatever the envelop- ment may be, surrounding the fat-globules, is loosened or cut. Biological Changes.—Cream when put into the ripening-vat usually contains a very large variety of bacteria. Which species predominates at that time depends upon the care and treatment of the cream previous to the ripening stage. In pasteurized cream practically all the germs present are of the spore-producing kind, and unless conditions are favorable for the development of the spores, these will be suppressed by the germs added with the starter. During the first few hours of the ripening process there is a gradual growth of all the germs present. It is said that in sweet cream the lactic acid germs are comparatively few in number, but under favorable conditions these grow so much more rapidly in number than any of the others, that in a short time they become more numerous than all the other germs. The by-product lactic acid is unfavorable for the growth of nearly all the undesirable varieties of germs. Practically all these germs are suppressed in their development, CREAM-RIPENING 211 so that when cream is ripened properly, it contains few other germs besides those which produce lactic acid. From the above it will be seen that there are practically two overlapping periods in the bacterial changes during the ripening of the cream, and especially is this so in the ripening of raw cream. The first includes the period when all the different varieties of germs grow, and the second includes the period when only the lactic-acid-producing germs grow. It is, there- fore, maintained that before the churning takes place the ripening of cream should be carried on to such an extent that the lactic-acid germs only predominate. Dr. Storch, who has made a detailed study of this, asserts that milk and cream both have a rather undesirable flavor at the beginning of its ripening period, while in the latter stage of the ripening period it takes on a pleasant, clean, acid taste. The number of germs, and the relative number of acid-pro- ducing germs in the cream when ripened, is as shown in the following table: * i mber Aci Per r Non- (er Date erty of Number per c.c. | ee Sed ¢ ent N Pelee plan Ne acl Feb. 11 | Fine 280,000,000 | 257,000,000 | 92 | 22,400,000 | 8 Jul: 18° | Poor eases ssaeessuhsvosmes es ese | percefeawacs Bae ce 19 ‘© 30 | Excellent | 3,002,000,000 | 2,851,190,000 | 95 [150,810,000 | 5 Aug. 11 | Good 1,107,000,000 | 1,012,072,200 | 91.5) 94,928,800 | 8.5 Sep. 3] Fair 1,027,000,000 | 955,110,000 | 93 | 71.890.000 | 7 os 5 | Good 2,007 958,000 | 1,827,370,000 | 91 {180,588,000 | 9 Oct. 28 us 392,958,000 | 385,098,840 | 98 7,859,160 | 2 «30 si 393,700,000 | 381,889,000 | 97 11,811,000 | 3 Eckles found that when good-flavored cream is ready for churning the number of bacteria per cubic centimeter varies from 380,000,000 to 3,000,000,000. Of this number the acid- producing bacteria constitute from 91% to 98%. Chemical Changes.—The changes in cream during the process * Bul. 40, Iowa Experiment Station. 212 BUTTER-MAKING. of ripening are not due to any instability of the components of cream, nor are they attributed to any of the enzymes. Galactase is a pre-existing enzyme in milk; consequently it would be present in cream, but present only to a very small extent. If it were possible to exclude from the cream all the different kinds of bacteria, ripening would not take place. At least it would proceed at a much slower rate than the ordinary rate of change in the ripening of cream ; this proves that the solids of cream are chemically stable and that the enzymes or unorganized ferments play only a secondary part in bringing about the different changes in cream ripening. There are two classes of solids in cream which are decom- posed chiefly during ripening: viz., (1) Albuminoids, and (2) Sugar. 1. Most authorities maintain that bacteria are unable to feed on, or to decompose directly any substance which is not present in the form of a solution. As casein is not normally present in a solution in milk, the pre-existing enzymes or bacterial by-products must cause the first decomposition of casein before the germs are able to utilize it. The by-products resulting from the casein ferments are many, and very com- plex. According to Russell * albumoses, leucin, peptone, tyrosin, and ammonia are formed. Freudenrich claims that in addition to these butyric acid is a by-product. Besides these substances, gases such as carbonic gas, marsh-gas, and nitrogen are formed. Whether all these by-products are formed directly or indirectly or both, no one knows for certain. The typical ferments seem to act similarly upon the casein in milk. They produce first a rennet-like ferment, which curdles the milk. After it has been curdled, the curd is digested or peptonized by the action of some enzyme. The casein in a sample of milk containing a preponderance of casein ferments will in a few weeks, or even less time, disappear entirely. Ap- parently the milk has been transformed into whey. This particular ferment is called casease by Duclaux. Conn calls * Dairy Bacteriology. CREAM-RIPENING. 213 it a tryptic ferment, because it is similar in its action to the trypsin produced by the digesting glands. The putrefactive germs ordinarily act upon the nitrogenous matter of cream, as described above. 2. The milk-sugar in cream is present in a perfect solution, and consequently it is thought that bacteria are able to utilize it as food directly. The typical lactic-acid-producing germs cause the milk-sugar to split up into lactic acid chiefly, accord- ing to the following equation: C12H22011 + H20 = 4C3H603. Milk-sugar. Lactic acid. There are a number of germs which are able to produce lactic acid from milk-sugar, but practically all of them, so far as known, produce other by-products besides the lactic acid. Some germs produce much lactic acid and a small amount of other by-products, while other germs produce little lactic acid and large amounts of several other by-products. Some of them break up the milk-sugar and change it into lactic acid and car- bonic gas. Other species produce lactic acid and alcohol. This latter species Grottenfelt claims to be closely associated with the production of flavoring substances in butter. Different kinds of gases, such as nitrogen, hydrogen, carbonic-acid gas, and marsh-gas are also formed. It is doubtful whether there are any germs which are able to transform milk-sugar entirely into lactic acid. If such were the case, 1 gram of milk-sugar would produce 1 gram of lactic acid. According * to some experiments carried on by one of the authors, .8 of a gram was the maximum amount of acid developed from 1 gram of milk-sugar, and .5% is the average amount of acid developed from 1 gram of milk-sugar. In the experiments, efforts were made to have the typical lactic-acid ferments present in the cream. The following table may prove of some interest: * Chemical Changes during Cream Ripening. (Thesis I. S. C.) 214 BUTTER-MAKING. Cream I. Sugar. Acid. Pet Ba ae 1st ripening period.......... .1% produced 04% 83% 2d ue PS Sia Geese Che als 1 ae .06 .395 Cream II. Ist ripening period.......... .1% produced 08% 58% 2d es OB, ahah Daehn wl ne .06 .64 3d we SE asd te atest 1 ef .045 -82 Cream ITI. 1st ripening period.......... .1% produced -051% 58% 2d ot ES gies. 6a aes ane 1 ee 050 63 -3d aE OO ean ailalitees me e .016 -68 Average of 8.experiments... —.1 ee 05+ Conn states that the lactie acid produced in cream during ripening is not always of the same kind. Some species of bacteria produce the kind which turns the plane of polarization to the left; other species produce the kind which turn it to the right, and still other species produce the so-called inactive lactic acid. The most common are those which produce acid that turns the plane of polarization to the right. The souring of cream, according to Conn, is not due to the development of lactic acid alone. Two kinds are produced, (1) fixed, and (2) volatile. The fixed acids appear to be chiefly, if not wholly, lactic acid, and the volatile are chiefly acetic and formic acids. The fixed acids are produced in the greatest proportion. In the table quoted above, it will be seen that during the first ripening period of sample 3, .1% sugar produced .051% of acid, while during the last or third ripening stage .1% of sugar produced .016% of acid, being only about one-third of that produced during the first ripening period. The same is true in experiment II, where three separate analyses were made of the cream. It is difficult to account for the constant decrease of lactic acid in proportion to the sugar decomposed in the advanced stage of the ripening period. Is it the lactic acid already present that decomposes into other products when so much acid is formed? Or do the bacteria continue to decom- pose the sugar, but the by-products being of a different nature? CREAM-RIPENING. 215 Or do certain species of bacteria cease to act, and are other species, which produce less lactic acid and more gaseous prod- ucts, able to perpetuate their growth and bring about the results observed? The results are probably due to a com- bination of the different actions just mentioned, but the most likely theory is that conditions for the growth of other species of bacteria become more favorable, and other by-products than lactic acid are formed, products that cause the undesirable rancid flavors in over-ripened cream. Butyric acid also results from the decomposition of cream constituents during ripening. The origin of the butyric acid formed during ripening is, however, not well known: Freuden- reich says it is the residue resulting from the breaking down of casein and milk-sugar in various ways, and therefore he classes the butyric ferments in the same group as the cascin ferments. Butyric acid in overripened crcam is by some authorities considered to be a direct product from an excessive amount of lactic acid. Each molecule of lactic acid breaks up into butyric acid, carbonic-acid gas, and hydrogen, according to the follow- ing equation: Carbonic- acid gas, 2C3H.60s —s C3H7CO2H + 2CO2 + Ha. Lactic acid. Butyric acid. Hydrogen. It is questionable whether this reaction ever occurs in the ripening of cream. Butyric acid also results from the decomposition of butyrin, through the action of bacteria, and causes the molecules of fat to split up into butyric acid and glycerine, according to the following equation: Butyrin (fat). Water. Glycerine. Butyric acid, C3H7CO2 OH C3Hs ; CsH7COg + 3H20 = CsH; ;}OH + 38C3;H;CO.H | CsH7CO2 | OH CHAPTER XV. STARTERS. Definition._—By the term starter, in cream-ripening, we understand a medium containing a preponderance of desirable germs present in a virulent condition. History.—The use of starters in the dairy industry dates back a great many years. The fact that starters helped in the manufacture of dairy products was recognized years ago by practical men even before scientists recommended the use of pure cultures. In European dairy countries the use of the buttermilk borrowed from a neighboring factory to add to the cream in order to overcome abnormal conditions, was a common occurrence. In Holland, sour whey borrowed from some other factory was used to overcome gassy fermentation in cheese- making. While the reasons for this were not well understood, the underlying principle was involved, viz., that of overcoming the undesirable fermentation by adding ferments of an an- tagonistic kind. The introduction of pure cultures, or commercial starters, for cream-ripening dates back to 1890, by Professor Storch. He recommended their use in creameries in Denmark. Starters were used in that country for a time successfully, and since then starters have been introduced and extensively used in this country, as well as in practically all European countries. Classification of Starters.—Generally speaking, the different kinds of starters are included under the names (1) Natural, and (2) Commercial. The latter is prepared from a pure culture of bacteria obtained from the laboratory. The former, or natural, include a great many kinds of dairy products which 216 STARTERS. 217 are supposed to contain a preponderance of those germs which are involved in the production of desirable flavors in butter. Buttermilk, sour cream, whey, and sour whole or skim-milk, are classed under this heading. While all these may be termed natural starters, and at certain times the use of any one of them may produce better results than if no starter at all were used, it is not safe to rely upon these to bring about better results than could be obtained without the use of starters, because these products are likely to be contaminated in a large degree with undesirable germs. Preparation of Natural Starters—-The best natural starter is usually obtained by selecting a number of different samples of the best milk coming into the creamery, into cleaned sterile glass jars. The samples are allowed to stand until sour at about 70° F. The sample which coagulates into a smooth uni- form curd, and has a pleasant acid taste and smell is selected and used as a mother-starter. When inoculated into a large quantity of selected pasteurized skim-milk, cooled to ard kept at a temperature of about 70° F. until it begins to coagulate, it will usually produce a starter which is equal, and often superior, to a commercial starter. Commercial Starters, or Pure Cultures.—Experiments have amply proved that certain species of bacteria are chiefly re- sponsible for the butter flavors developed in cream during ripening. This fact has given rise to the use of pure cultures prepared in a commercial way. These pure cultures contain, in a virulent condition, the germs which produce the desirable flavors and aroma. The cultures are put up in laboratories specially provided for this kind of work. The germs are iso- lated and inoculated into a medium which is suitable to their growth. Some laboratories inoculate them into a liquid medium, others into a powder medium. The liquid medium consists usually of sterilized bouillon, or milk. The powder medium consists chiefly of milk-sugar. The cultures that are put up in the liquid form will not keep so long, and it is not safe to use them after they are about nine days old. The cultures which 218 BUTTER-MAKING. are put up in powder form have the advantage that they can be kept for a much longer time and still retain their vitality. Both kinds as a rule are good while they are fresh. We give below a list of the commercial cultures with which the authors are familiar: S. C. Keith, ) Lactic Acid Culture.) Charlestown, | Duplex Culture legiomaae Mass. Boston Butter Culture O. Douglas, Boston Butter Culture ] Boston, Duplex Culture | Liquid. Mass. Lactie Acid Culture Eloc Ericsson, | 7; , 1 Se, Paul, [tue s Butter Cul- | rigui d. Ameri- Minn. J ean Hansen’s, | Little Falls, oe Ferment Powder. Park Davis &Co., } This culture is put up ears Detroit, i Flavorone | in tablet and cap- Starters } Mich. sule forms. Conn’s Culture, | Storr Station, i Bacillus 41 Liquid. Conn. Blauenfeldt & Tvede, Copen- | ear pe Acid Powder: hagen, Den. | ere Bey & Fog’s ‘ Lab’t Cul. Foreign Co penhagen. { Lactic. Den. ] S. P. Storm, } Tillitze, Naks- ee kov, Den. Preparation of Commercial Starters—All of the starters mentioned above have been tested and are known to produce good results. The first step in the preparation of a mother- starter (starterline) is to prepare preferably a glass jar or bottle by thoroughly cleaning and sterilizing it. Glass jars are used in preference to any other vessel, because if they are un- clean in any way, it will show through the glass. Secondly, there are no seams and no places on the inside which will cor- STARTERS. 219 rode, and in that way retain unnoticeable dirt. Mason jars and sampling bottles are suitable. The kind of bottle which is used for marketing milk gives very good results. The second step consists in selecting suitable milk. The milk must be in as pure and sweet a condition as possible. A good starter can be produced from either whole or skim-milk. Skim-milk, however, is preferable to whole milk. The mis- take of selecting whole milk for starters has often been made. The mother-starter prepared from whole milk usually has a more pleasant, mild, rich taste, due to the fact that it contains more fat than the starter made from skim-milk. The mother starter prepared from good skim-milk is preferable, and safer to rely upon. Efforts should be made towards separating the starter milk before the rest of the milk has been run through. Tf not separated till late during the run of the day, the separator is filled with slime and bowl-slush, which are likely to con- taminate the starter milk. At some creameries, the separation of the starter milk is accomplished with a small hand sepa- rator. This, however, is not convenient or practicable at most creameries. The milk for the starter can be selected and run through the power separator during the beginning of the run. It is well not to use the very first milk which passes through the separator, asit would be likely to contain a greater number of undesirable germs. The milk which has been selected for the mother-starter, or starterline, is then pasteurized. The pasteurization is best accomplished by the intermittent method. If considerable milk is to be pasteurized it is best to make use of a clean, sterilized can. If only a small portion is to be pasteurized, just enough for the mother-starter, the milk can be put di- rectly into the jars. The jar half full is about the proper amount of milk to use. The directions sent with some pure cultures recommend as much as half a gallon or a whole gallon of milk. As a rule better results are obtained if only about a pint of milk is taken. If the milk for the mother-starter is pasteurized in the glass bottles or jars, then it is advisable to set the bottles 220 BUTTER-MAKING. containing the milk into cold water,—covering the jar so as to prevent outside contamination,—and then heat up the water gradually. Care should be taken not to insert these bottles suddenly into scalding hot water, or to let the steam strike them, for either is likely to crack the bottles. Care should be taken also to exclude water from milk used for starters. It is advisable to heat this milk, for the starterline, as high as possible in scalding water, say up to about 200° F. The sample may assume a cooked taste, but this will soon disappear after the starter has been carried on a few days. The milk should be left at this high temperature for about ten or fifteen minutes. A longer time does no harm. Then the milk is gradually cooled to about 80° F. This high temperature is desirable, because the germs present in the commercial cul- ture may be somewhat dormant. This high temperature would tend to revive them more quickly than a lower temperature. Great care should always be taken to cool the milk previous to inoculating it with the pure culture, otherwise the germs present in the pure culture will be destroyed. Inoculation.—The next step is to inoculate the prepared milk with the pure culture obtained from the laboratory. The bottle which contains the pure culture is carefully opened, then the bottle containing the culture is turned over and emptied into the pasteurized milk. The bottle should be held down closely to the mouth of the jar containing the sterile milk, in order to prevent too much contamination from the air. Then the milk containing the pure culture is thoroughly stirred and set away in a room where the temperature is about 70° F. This will gradually cool the milk from 80° to 70° F., and in about twenty to forty hours the milk will sour and coagulate. Germs in nearly all of the liquid cultures are rather slow in acting upon the milk, undoubtedly due to the dormancy of the germs, and to a comparatively few of them being present in the pure culture. When the powdered cultures are used, a little more care is essential to get the powder thoroughly min- gled with the milk. It is a trifle more difficult to get the STARTERS, 221 powder thoroughly mixed with the milk than it is to get the liquid cultures mixed. If anything is used with which to stir the sample, it should be sterilized before coming in contact with the milk. This applies in the preparation of all cultures. In testing or sampling the mother-starters, nothing should be allowed to come in contact with it unless it has previously been thoroughly sterilized. The powder cultures are usually more vigorous in their effect than most of the liquid cultures now on the market. The powder cultures usually coagulate the sample in about twenty-four hours, and if the operator is used to handling the liquid cultures, he should watch the mother- starters prepared from powder cultures, so that they do not get overripe. It is very essential that the starters do not get overripe. The time when the germs are most numerous and most active in the starter is about the time when the sample coagulates. As soon as this stage has been reached, or just previous to coagulation, the starter should be cooled down to at least 50° F., or lower if possible. This prevents any further growth of germs and the sample can be kept a short time without injury. Directions usually accompany each of the cultures, but the above will be found to produce good results with all of those mentioned in the above outline. By inoculating from 2% to 5% or more of the mother- starter into a large sample of pasteurized milk, any desired amount of starter can be prepared. In selecting this amount of milk, as much care as possible should be taken in order to select the best kind of milk, and keep it from being contaminated. When this large sample of starter is at the proper stage of coagulation, it should be’used at once, or else cooled down to about 50° F. The amount of mother-starter with which to inoculate the large sample of starter may vary a little with- out any bad effects. If the large sample of starter is to be ready for use in a short time, a larger portion of the mother- starter can be used for inoculation. If the temperature at which the starter is set and the amount of mother-starter used 222 BUTTER-MAKING. for inoculation are the same from day to day, the starter will be ripe at nearly the same hour every day, and, consequently, more uniform ripening results can be obtained. The notice- able coagulation of the starter when skim-milk is used will usually take place when there is about .6% of acidity. A slight coagulation will take place when there is about .5% of acidity, but it is hardly noticeable. The coagulation-point may vary with different samples of milk. If a mother-starter is to be kept any length of time it should be inoculated into a sample of good fresh pasteurized milk about every other day. If a mother-starter, or starter of any kind, is allowed to stand too long at a low temperature, the desirable germs will become dormant, and some undesirable germs will gradually gain a foothold. It is a good plan to carry any mother-starter along for two or three days before it is used to inoculate a large sample of milk. When the mother- starter is first prepared it sometimes contains an undesirable taste and smell from the medium in which the germs were put up at the laboratory. This smell and taste is eliminated by carrying it on two or three days previous to its use. While the starter, or mother-starter, is in the stage of ripening it should occasionally be gently stirred. As soon as coagulation of the milk begins, then starters of any kind should never be stirred. If a sample of coagulated milk is stirred before it is ready for use, it is more likely to ‘‘ whey off.” Length of Time a Starter Can be Carried.—In this country, even if special precautions are taken, it seems almost im- possible to carry on a starter for more than four weeks without having undesirable ferments enter. The length of time a starter can be carried undoubtedly depends-upon conditions, and the care with which it has been handled. When a starter is properly prepared, cooled gradually before coagulation, and not overri- pened, it will contain a smooth soft curd, and retain its mild acid flavor for at least a month. The Danes, who use starters in butter-making more regularly than any other people, are able to carry a starter along for six months or more without renewing it. STARTERS. 223 It is a good plan to keep at least two different kinds of starter by carrying them on from day to day in small quart jars. Then if one should happen to “go off,” the other one can be used instead. Poor Starters. — Many unsuccessful results from the use of starters for cream-ripening have been reported. The failure can be traced to the improper use of starters. If starters are good they will never bring about poorer results than are ob- tained without the use of them. Owing to the fact that it is difficult to keep the same starter in a good condition very long, many starters are used which develop abnormal fermenta- tions in cream. A slightly acid, somewhat bitter taste, and a slimy condition of the starter are defects which are very com- mon. These conditions seem to be brought about chiefly by overripening it at a high temperature, and keeping it a long time at a low temperature before using it. Slimy fermenta- tion is very common in starters which have been carried on for a time, Whenever this slimy ferment develops in the starter it can be noticed in the cream and starter both, by the acid not developing so rapidly as when the proper acid-pro- ducing ferment is present. It seems almost impossible to develop any more than about .5% of acidity in 30% cream; while if the proper ferment were present, about .7% could be developed. A decrease in the quality of butter accompanies the development of this ferment in the cream. Whenever it is found that a starter is not in as good condi- tion as it ought to be, it should not be used, as a poor starter is worse than none at all. The buttermilk from the previous cream can sometimes be used advantageously until a new starter can be prepared. Underripening and Overripening of Starters. — The effect of overripening starters has already been mentioned under the “Preparation of Mother-starters.” The question of under- ripening starters is also of importance. It is a well-known fact that just about the time when the milk begins to turn sour, that is, when the sourness can just be recognized by the taste, 224 BUTTER-MAKING. it has a rather disagreeable flavor. After more acid develops the undesirable flavor largely disappears, and the milk assumes a clean, desirable acid taste. The reasons for this has recently been accounted for by Storch, the well-known authority on starters. He claims that this disagreeable flavor is due to the action of undesirable organisms, during the first souring stage. As the souring progresses these germs are subdued and grad- ually crowded out by the desirable acid-producing types. In the preparation of a starter the probabilities are that some of these undesirable types of germs are present. At least it is safer to go on the assumption that they are present. This makes the underripening of starters just as important to guard against as overripening. Amount of Starter to Use.—The amount of starter will vary under different conditions. It may vary from none at all the as much as 50% of the cream to be ripened. The quality of cream is one of the factors that needs to be considered. Raw cream and old cream each require a large starter, especially if the cream is thick enough so as to permit of being reduced in thickness. Good pasteurized cream does not need a larger starter than about 10% of the cream to be ripened. The amount of starter to use also depends somewhat upon the general creamery conditions. In some creameries all the cream is received in a very sour and poor condition, and facili- ties for getting milk for preparation of starters are often very poor. Under such conditions it is questionable whether it would be profitable to use starters at all. The amount of starter to use chiefly depends upon the degree of rapidity of ripening desired, and upon the temperature of the cream. If it is desirable to ripen quickly, then a comparatively large starter (15% to 25%) should be added, and the ripening temperature should be comparatively high (about 80° F.). If slow ripening is desired, then less starter can be used. Enough, however, should be used to control the fermentation in the cream (about 10% to 15%), and the ripening temperature may be lower, between 60° and 70° F. More starter should be used in the winter. STARTERS. 225 Use of Starter-cans.——In the past, ordinary tin shot-gun cans have chiefly been used for the preparation of starters, and have given good results. Many makers still use such cans in preference to recently invented starter-cans. Fie. 133.—The Victor Fie. 134.—Emily’s perfection starter-can. starter-can. The earliest starter-cans were made of light material and did not last long. These defects, however, have largely been done away with, and the use of starter-cans certainly is an improve- ment over the old method of preparing the starters in several smaller cans. These starter-cans are jacketed, so that the temperature can be controlled by using hot or cold water, or ice, as demanded, in the jacket. All of the starter-cans have an agitator, which is operated with a belt. CHAPTER XVI. CHURNING AND WASHING BUTTER. Definition —By churning we understand the agitation of cream to such an extent as to bring the fat-globules together into masses of butter of such size as to enable the maker to separate them from the buttermilk. The agitation may be brought about in several different Fia. 135.—Ancient method of churning Fic. 136.—The Dash churn. in skin bags. ways, and by different shaped devices, which are called churns. The methods of churning, like the process of separation, began’ with primitive methods. The ancients churned their milk, without separation, in bags made from the skins of animals. The next step in advance was to place milk or cream in bottles or jars, and then to shake them. This latter method of churn- 226 CHURNING AND WASHING BUTTER. 227 ing cream in bottles is yet in use in many of the smaller house- holds of Europe, where the amount of cream is limited to a small quantity donated by cow-owners. The next step toward churning on a large scale was to get a large wooden box or barrel run by power or by hand. The churns which are in use at the present’ time in American butter-factories are termed “combined churns.” They are so arranged as to admit of churning, washing, salting, and working without removing the butter from the churn. This style of churn is now being in- troduced into Europe. Owing to their superior worth they will soon be in general use there as well as here. They keep flies away from the butter during fly time; the temperature of the butter can be controlled in the churn, and the handling of the butter during salting and working is obviated. ConpDiTIONS AFFECTING THE CHURNABILITY OF CREAM. Temperature.—The temperature of cream is one of the most influential factors in determining the churnability of cream. Fic. 137.—The Dairy Queen combined churn. The higher the temperature of the cream, the sooner the churn- ing process will be completed. Too high a churning tempera- ture, however, is not desirable. It causes the butter to come in soft lumps instead of in a flaky granular form. This is deleterious to the quality of the butter. It causes, first, a greasy texture of the butter, and, secondly, it causes the incorporation 228 BUTTER-MAKING, in the butter of too much buttermilk. This buttermilk contains sugar, curd, and water, which, when present together in butter, are likely to sour and in other ways deteriorate the butter. Curd and sugar should be excluded from butter as much as possible, in order to eliminate food for bacteria which may be present. An excess of curd is also favorable for the forma- tion of mottles.* Too low a temperature is also undesirable, although it is CHURN EAN Mavauer § Fie. 138.—The Victor combined churn. better to have the temperature a little low rather than too high. When the churning temperature is too low, difficult churning is likely to occur. Cream at a low temperature becomes more viscous. On agitation in the churn such cream if it is very thick will adhere to the sides of the churn and rotate with it without agitating; consequently no churning will take place. Too low a temperature brings the butter in such a firm condi- tion that it takes up salt with difficulty, and when this hard butter is being worked, a large portion of the water in the * Bul. No. 263, Geneva, N. Y. CHURNING AND WASHING BUTTER. 229 butter is expressed, and the overrun will be lessened to a great extent without increasing the commercial value of the butter. The degree of hardness of the fat in the cream is the govern- ing factor in deciding the churning temperature. The churn- ing temperature will vary a great deal in different. localities. The hardness of the fat depends upon (1) the season of the year; (2) the individuality of cow; (3) the stage of lactation period; Fic. 189.—The Squeezer combined churn. and (4) the kind of food fed to the cows. All these factors influence the melting-point of butter-fat. The higher the melting-point of butter-fat is, the higher the churning tempera- ture, and the lower the melting-point of the fat, the lower the churning temperature. 1. During the spring the cows yield milk containing a larger proportion of soft fats; consequently the churning tempera- ture is always lower in the spring than in the fall or winter. During winter, when the cows are fed on dry food chiefly, the harder fats increase in quantity, and consequently a higher churning temperature is necessary during that time. 2. Some animals produce milk containing a larger proportion of softer fats than do other animals. It is said that the differ- ence in this respect is more marked in certain breeds. It is maintained that the cows of the Jersey breed produce milk con- taining a larger proportion of the softer fats than do any of the other breeds. 3. The period of lactation also affects the melting-point of butter-fat. When a cow is fresh she yields a larger proportion 230 BUTTER-MAKING. of the soft fats than she does later on in the lactation period. With this increase in the proportion of the hard fats in the advancement of the lactation period, the fat-globules become smaller. This, together with the increased hardness of the fat, causes difficult churning at times. It can readily be seen that the larger the fat-globules are the greater are the chances for these globules to strike each other during agitation in the churning process. 4. The nature of the food fed affects the melting-point of butter to a considerable extent. Cotton-seed and its by- Fig. 140.—The Disbrow combined churn. products have been demonstrated thoroughly by several investi- gators to cause butter to become hard. When a large amount of cottonseed is fed, the butter assumes a crumbly, tallowy, hard condition; while linseed meal, and practically all succulent foods tend to decrease the melting-point of butter-fat. According to the above it can be concluded that the churning temperature may vary between wide limits, but the average desirable churning temperature under normal conditions is CHURNING AND WASHING BUTTER. 231 between 50° and 60° F. Any conditions which tend to harden the butter-fat will require a comparatively high churning tem- perature; and any conditions tending to soften the butter-fat will require a lowering of the churning temperature. The lower the temperature at which the churning can be success- fully accomplished, the more complete will be the churning; that is, the less fat will remain in the buttermilk. ) Fic. 141.—The Simplex combined churn, with worker detached. Richness of Cream.—The amount of fat in the cream affects the churnability of it considerably. The richer the cream the sooner will be the completion of the churning, that is, providing the cream is not rich enough to be so thick as to cause the cream to adhere to the inside of the churn and thus escape being agitated. If rich cream is churned at a high temperature the butter will come in a remarkably short time, providing all other 232 BUTTER-MAKING. conditions are favorable. Thin cream churns much more slowly, and can be churned at a higher temperature than thick cream, without injuring the quality of the butter. When rich cream is churned at a high temperature, and the butter comes in a short time (about ten minutes), the butter will usually be greasy in body, and will contain a great deal of buttermilk, which will be more or less difficult to remove on washing. When thick cream is being churned, the butter does not break in the form of small round granules, as it does when thin cream is churned. When thick cream is churned at as high a temperature as is consistent with getting a good texture, the best results are obtained. In the first place, rich cream produces less butter- milk, consequently less fat will be lost in the buttermilk. This would tend to increase the overrun. Secondly, the breaking of the butter at the end of the churning will be such as to cause the granules to appear large and flaky, rather than small round granules. The more flaky granules of butter will retain Fic. 142.—The Simplex churn with worker attached. more moisture than the small, harder granules under the same treatment. Experiments show that when different thicknesses of cream (thin cream containing on an average 22% of fat, and thick cream 36% of fat) are churned, there is a difference of about 3% in the moisture-content of the butter. The CHURNING AND WASHING BUTTER. 233 average churning temperatures of cream and wash-water in these experiments were 56° and 53° F. respectively. When thick cream is churned, and the temperature is moderately high, it is almost impossible to churn the butter into granules. This condition causes butter from thick cream to contain more moisture than butter from thin cream. Amount of Cream in Churn.—When the churn is about one- third full, the greatest degree of agitation is obtained, and con- (| all Limit i a “AAG HI Im «a T_T ~Say] vo A Hi, Cn mul mii rt (9) a lame iid RS ee aH orl —t = Fic. 143.—Danish churns and frame for holding them. sequently a quicker churning. If a small amount of cream is being churned, it is often difficult to gather the butter properly. Tf the cream is thin, the granulesare thrown about in such a way that they are gathered with difficulty. If the cream is thick, the small amount of cream will adhere to the inside of the churn, and in that way delay the completion of the churning. It is a common opinion that less overrun is obtained from 234 BUTTER-MAKING. a small churning than from a large churning. It issafe to say that if it were possible to maintain all conditions alike, especially as to temperature and degree of churning, there would be no difference in the moisture-content of the butter made from churnings of different sizes. When there is only a small amount in the churn, the atmospheric temperature is likely to raise or lower the temperature of the cream. If the atmosphere is warm, then the butter from the small churning is more likely to be soft. A small amount of cream in the churn is also more likely to be overchurned than a larger amount of cream. These two factors would tend to increase the amount of water in the butter. In mixing the salt with a comparatively large amount of butter, less working is necessary. Much of the butter is mixed in the churn without going through the workers, and con- sequently less moisture will be expressed from the butter. With the same number of revolutions of the churn the butter from the small churning is worked correspondingly more than the butter from a larger churning. Medium firm butter, to a cer- tain limit, loses about .2% of moisture for every revolution that it is overworked in the absence of water. Degree of Ripeness.—The riper the cream is, all other con- ditions being the same, the easier it will churn. Sweet cream is viscous, and consequently the fat-globules will not unite as readily. The acid developed in the cream seems to cut or reduce the viscosity of the cream, although it causes it to become thicker in its consistency. Cream in an advanced stage of ripening is brittle, so to speak. That is, if a sample of the properly soured cream is poured from a dipper it will not string but break off in lumps. If very thin cream is overripened, the curd is coagulated. When this thickly coagulated cream is churned, the solid curd breaks up into small curdy lumps. These small lumps of curd are likely to incorporate themselves in the body of the butter and injure its quality, and also its keeping quality. If thin cream has been overripened, it should be strained well, and care should be taken not to churn it to such a degree as to CHURNING AND WASHING BUTTER. 235 unite the granules into lumps before the churn is stopped. By stopping the churn while the butter is in a granular form, the most of these curdy specks can be separated from the butter by copious washing. Some specks are likely to remain in the butter when the cream is in such a condition, but by following the above plan enough of the specks can be removed from the butter so that it will not injure its commercial quality. The degree of ripeness of cream does not have any effect upon the Fig. 144.—The churn-room in Trifolium Creamery, Denmark, composition of the butter, except in increasing the curd con- tent, as mentioned. oa Nature of Agitation.—The nature and degree of agitation of cream affect the churnability considerably. Many different kinds of churns are on the market at the present time. The ro- tary drum-churns, now used almost universally in this country, are claimed to give the greatest degree of agitation; that is, providing the churn revolves at a proper rate of speed. If 236 BUTTER-MAKING. the speed is so great as to cause the cream to be influenced by the centrifugal force generated, rotating it with the churn, then no agitation will take place. Consequently the churning process will be delayed, if not entirely prevented. If the speed of the churn is too slow, the degree of agitation of the cream will not be at its maximum, as the cream will tend to remain at the lowest portion of the churn without being agitated. In the old-fashioned dash-churn the cream was not exposed to much agitation. In Europe the upright barrel-churn with rotary stirrers inside is mostly used. It takes longer to churn in this churn than in American churns. However, it gives good satisfaction. The proper speed of the combined churn,—that is, the speed at which the greatest degree of agitation is brought about,— cannot be given here, as it varies with the different diameters of the churns. The directions given with the churns from the manufacturing companies should be followed. So far as known the quality and composition of butter obtained from churning at a low speed, and at a rapid speed, do not vary. Size of Fat-globules.—Cream containing large fat-globules churns more quickly than cream containing small globules. A more exhaustive churning can also be obtained from cream containing mostly large globules. It is, however, impossible to obtain cream which does not contain any of the small globules. The minute globules are always difficult to remove from the serum, whether it be in the churning or in the separation. In the churning there is a certain force which always tends to hold the globules in place. This force acts in a correspondingly greater degree upon the small globules. They are held in position and move only when the cream is exposed to agitation. Cream containing larger globules allows them to escape from their position with greater ease than does cream containing the minute globules. The globules which are not removed from the buttermilk during the churning process are largely of the small type. 237 Churn-room in Hazlewood Creamery, Portland, Oregon. Fig. 145. 238 BUTTER-MAKING. Straining of Cream.—Before the cream is transferred from the ripening-vat to the churn it should be strained through a fine perforated tin strainer. This can be conveniently done during the changing of the cream from the ripening-vat to the churn. Special strainers are now manufactured which can be hooked onto the churn, and the cream can run directly from the ripening-vat through the strainer into the churn. This straining of the cream separates all the lumps which are likely toappear. It also separates any other coarse impurities which may be present. If these impurities were not sepa- rated they would. probably be embodied in the butter and cause an unsightly appearance. They would also be likely to injure the keeping quality of the butter, but this would depend, of course, upon the character of the impurities. Fig. 152. Fig. 153. Fig. 152.—Filter-can: 1, overflow; 2, inlet of tap-water; 3, outlet of filtered water. Fic. 153.—Cross-section of filter-bed and can: 1, overflow; 2, inlet; 3, out- let of filtered water; 4, perforated galvanized-iron plate; 5, perforated galvanized-iron plate; 6, concave galvanized-iron plate with hole in center. (3) The rate of filtration is necessarily governed by the depth of the filter-bed, the character of the material used, and its fineness. The water passes through the charcoal, coke, and gravel quite rapidly, yet the substances are very strong barriers to the passage of micro-organisms. The sand layer does not admit of so rapid filtration. Fine sand, however, is one of the best filtering substances that can be had. The rate of filtration can be regulated by increasing or decreasing the CHURNING AND WASHING BUTTER. 253 depth of the fine-sand layer. In a general way, the slower the rate of filtration is, the more thorough it is; and, vice versa, the more rapid the rate of filtration, the more incomplete is the removal of the bacteria. If the filter-bed is constructed as described above, the rate of filtration will be about 18 gallons per hour, and about 96% of all the germs present will be removed, together with the impurities present in suspension. (4) The filter used at the Iowa Experiment Station was in constant use for about three months, without having been changed. At the end of this time it did as efficient work as at any previous time. The length of time a filter-bed can be used without being changed depends upon the purity of the water to be filtered, and also upon which kind of filtration is used, the continuous or the intermittent. The more impure the water which has to be filtered, the oftener the filter-bed should be changed. Whenever the rate of filtration is decreased to such an extent as to make the process impracticable, the filter-bed should be taken out and cleaned. If the water to be filtered is of average purity, a change of the filtering-mate- rial once every four months is ordinarily sufficient, no matter whether continuous or intermittent filtration is used. A filter-bed may do efficient work even a longer time than this. The same filtering-material can be used again providing it is thoroughly washed previous to replacing it in the filtering-can. Kinds of Filtration.—The two kinds of filtration in use are (1) Continuous, and (2) Intermittent. By the continuous method of filtration the inflow of water into the can is constant during night and day. The stream of water admitted into the filter-can is sufficient to cause the surface of the filter-bed to be covered with water all the time. This method excludes all oxygen from the filter-bed, except that which is in solution in the water. During the process of filtration a slimy coat is deposited on the fine sand. This seems to be the real agent absolutely necessary in order to eliminate bacteria by’a process of filtra- tion. A filter-bed without this slimy deposit on it simply takes 254 BUTTER-MAKING. out the coarse organic and inorganic matter held in suspension, without removing the bacteria. If some bacteria are removed with the matter held in suspension, others are carried along from the filter-bed. Owing to this, a new filter-bed must be kept in operation a few days before the filtered water can be considered pure and ready for use. The following table illus- trates how the germ-content of water is decreased as the process of filtration is carried on during the first few days: Filtered Unfiltered Water, Tap-water, Germs per Germs per Cc. c. cc. No. 1. Taken when filter-bed was first used......... 20,000 107 Oe Dan ne ae ne had worked 1 day..... 860 118 Lae: yam ss us ss «« 3 days..... 370 96 oe 4, ae “e oe ce “cc 5 iZ3 ey aed 48 54 ce 5. cé ce “ce 6é ce 7. ce ous 3 73 oe 6. fag oe ce “ec ce 9 “e Hoe hs 5 89 It will be seen from the table that during the first three days the filter-bed was in use the filtered water contained more germs than the unfiltered. Good results were not obtained until the seventh day. In order to be on the safe side it is best to expose the filter-bed to continuous filtration for about nine days before the water is used. The slimy coat referred to above is formed by certain germs. These germs then constitute the real agent of filtration. In order for these micro-organisms to do efficient work oxygen is essential. Well-water of average purity contains enough oxygen in solution without employing an intermittent process of filtration, and consequently for creamery purposes the con- tinuous method of filtration is to be recommended. Intermittent.—The intermittent process of filtration is used where comparatively impure water is being purified, such as in purifying water for large cities. If the continuous process of filtration were employed in such instances, the filtered water would not be free from germs, due to the fact that impure river-water does not carry enough oxygen in solution to supply the germs which form the real filtering agency. CHURNING AND WASHING BUTTER. 255 If the intermittent process is used, the first water filtered after the intervening period should not be used. During the intermission, or during the time that the water is shut off, germs develop and come through the filter-bed with the water that is filtered. Advantages of Purifying Wash-water for Butter.—The chief advantage of purifying wash-water for butter is that the keeping quality of the butter is improved, and if the proper skill and care have been applied in the other steps of manufacture, a pure sanitary product is obtained. The sanitary efficiency reached by purifying the wash-water constitutes no small consideration. Germs producing contagious diseases are thus checked from spreading. CHAPTER XVII. SALTING AND WORKING OF BUTTER. Objects of Salting.—The chief objects of salting are: (1) to impart a desirable flavor; (2) to increase the keeping quality of butter; and (3) to facilitate the removal of buttermilk. Amount of Salt to Use to Produce Proper Flavor.—The proper amount of salt to use in order to impart a desirable flavor depends chiefly upon the market. Some consumers prefer a medium high salt-content in butter; others, again, like butter which contains very little salt. The English market demands rather light-salted butter. In fact, this is the case with prac- tically all European markets. American markets, as a rule, demand comparatively high-salted butter, as much as will properly dissolve in the butter. Parisian markets and some markets in southern Germany require no salt in it at all. The salt-content of butter may vary between nothing and 4%. Butter containing as much as 4% salt is, as a rule, too highly salted. When it contains this much salt, part of the salt is usually present in an undissolved condition. Those who like good butter prefer butter that contains the salt thoroughly dissolved and well distributed. The amount of salt to be added should be based upon the least variable factor. Some creamerymen measure the amount of salt according to the amount of cream in the churn. While the box-churn and Mason butter-worker were being used, many makers preferred to weigh the butter as it was transferred from the churn to the worker. The method mostly in use now, and to be recommended, is to base the amount of salt upon the number of pounds of fat. The amount of salt to use per pound of fat 256 SALTING AND WORKING OF BUTTER. 257 varies, therefore, according to the conditions mentioned below, and also according to local conditions. Usually from half an ounce to one and a half ounces of salt per pound of butter- fat is most suitable. In whole-milk creameries the salt is often estimated per hundredweight or per thousand pounds of milk. To get the butter salted uniformly from day to day is very important, as a small variation in the salt-content has a greater effect upon the quality of butter than has a small variation in any of the other butter constituents. A variation of 1% to 2% in the salt-content can very easily be detected by the consumer, while that much variation in any one of the other constituents could not be readily noticed. The conditions upon which the proper amount of salt depend are: First, the amount and condition of moisture in the butter at the time the salt is added. If there is a great deal of loose moisture in the butter, more salt is necessary. This is due to the fact that the salt will go into solution in the water and be expressed during working. Secondly, it depends upon the amount of working the butter receives, and at what time the bulk of working is done, after the salt has been added. If the butter is medium firm, moisture in the form of brine is being expressed during the working. Consequently, the more butter is worked, up to a certain limit, the more brine is being expressed, and the more salt should be added to the butter. Thirdly, the amount of salt to add depends also upon the size of the butter granules at the time the salt is being added, and the hardness and softness of the butter. If the granules are very small and quite hard, they take salt with difficulty. The salt attracts also more moisture from these small granules than from larger ones, which will escape in the form of brine. If the butter is present in a rather soft, lumpy condition at the time the salt is added, and there is no water in the churn, very little salt is wasted in the form of brine, consequently less salt is necessary in the first place. It is undoubtedly due to these facts that the salt-content 258 BUTTER-MAKING. and the condition of salt in butter vary so much at the different creameries; they even vary considerably from one churning to another at the same creamery. If conditions are uniform in the creamery from day to day, the amount of salt to add to butter, and the amount of salt retained in the butter when finished, will be comparatively uniform. It should be mentioned in this connection that butter made from very good cream should not be salted too heavily. Butter made from a rather poor quality of cream may be salted corre- spondingly heavier. This is due to the fact that the heavy salty taste covers some of the undesirable flavors in the butter. If the butter-flavors are good, they should not be hidden by a heavy salty taste. If the butter-flavors are poor, then it may be policy to partially cover them up with a medium-heavy salty flavor. Effects of Salt upon Keeping Properties.—That salt is anti- septic is no longer a doubt. It has been domonstrated in laboratory work with butter that the growth of certain germs, isolated from butter, can be completely checked by the addi- tion of a certain amount of salt to the medium in which they are inoculated. Bouska* found that a yeast isolated from butter showed luxuriant growth in a medium containing 2% of salt in forty-eight hours, and only a trace in 4% of salt. The same germ showed only a trace of growth in a 6% salt medium after five days. The ordinary bread-mould, Penicillium glaucum, was iso- lated from butter and showed noticeable growth in a 9% salt medium in two days, and only a trace in a 10% solution during the same time. A spore-bearing bacillus isolated from butter produced only a trace of growth in a 4% salt medium. No growth occurred at all in a medium containing 6% of salt. Another gas-producing organism was also isolated from butter and only a weakened growth was produced in a medium con- taining 4% of salt. * Towa Ex. Sta., Bul. 80. SALTING AND WORKING OF BUTTER. 259 If it were practicable and consistent with the demand of the consumers, so far as the keeping properties of butter is con- cerned, it would be advisable to salt butter as highly as 6%. This much salt would tend to a large extent to check deterio- ration of the butter due to bacterial growth. That salt promotes the keeping quality of butter has also been demonstrated in a practical way during the Iowa Educa- tional Contest in 1903. Fifty samples of butter containing 23% or more of salt were scored off in New York, on an average, 2.38 points, while the remaining 171 samples containing less than 23% salt were scored off 3.54 points on an average; a difference in favor of the keeping quality of high-salted butter of 1.16 points. Most American markets demand a salt-content of about 24% in the finished product. Salt Facilitates the Removal of Buttermilk.—That salt facilitates the removal of buttermilk can easily be demon- strated by observing the escape of buttermilk from the butter immediately after the salt has been added and mixed with the butter. The first effect of salt when added to the butter is to precipitate the curd in the buttermilk. This precipitation is greater when a large amount of salt is added than when only a small amount is added. The precipitation of the casein in the buttermilk sets free the remainder of the buttermilk con- stituents; that is, when the casein is precipitated, the whey part assumes a more fluid condition and escapes, and the butter retains a portion of the curd. Owing to this action of the salt, it is essential that the butter should be as completely washed as possible, as otherwise it will retain an excessive amount of curd. The butter acts in a manner somewhat similar to a filter in removing a part of the curd from the other buttermilk constituents. Salt in Relation to Water in Butter Experiment has dem- onstrated that pure fat is not a salt-dissolving substance. Owing to this fact the only salt-dissolving substance in butter is water. As water will hold only a certain amount of salt in solution, it becomes evident that the amount of salt which 260 BUTTER-MAKING. can be properly incorporated in butter depends upon the amount of moisture present. The amount of salt which water will hold in solution at different temperatures varies somewhat according to differ- ent investigators. According to Gerlach * water will dissolve 35.94% salt at 58° F. This is approximately the temperature at which salt is worked into butter. Theoretically, butter containing 15% of water should be able to properly dissolve 5.4% of salt. Butter containing 13% of water should be able Fie. 154.—Action of salt solutions of different strength on the proteids of buttermilk. (Bul. 263, Gen., N. Y.) to properly dissolve 4.68% of salt, and butter containing 10% of water should be able to dissolve properly 3.6% of salt, etc. According to experiments conducted at the Iowa Experiment Station the maximum per cent of pure salt (NaCl) that could be properly dissolved in water of butter containing 16.92% of moisture, when worked 18 revolutions at intervals during two hours, was 16.57%. When butter was worked the same number of revolutions at intervals, and was allowed to dissolve * Kemiker-Kalender, p. 219. SALTING AND WORKING OF BUTTER. 261 only one hour, the amount of pure salt (NaCl) that was dissolved in the water of the butter containing 11.58% moisture’ was 14.09%. This undoubtedly will vary with different brands of salt. It will thus be seen that the property of water to take up salt is seemingly lessened when the water is present in a state of minute division, as it is in butter. In the first instance quoted the butter completely dissolved about 2.7% of pure Fig. 155.—Volumes of the same weight of salt of various brands. (Bul. 74, Wis.) salt; and in the second instance it dissolved only about 2% during one hour. Condition of Salt when Added.—The condition of salt when added is a very important question to consider in order to get enough salt properly incorporated. The amount of influence which the quality of the salt has upon flavor has recently been a subject of attractive interest, for many of our best butter- judges have made the charge that certain undesirable flavors in butter can be traced to the use of a poor quality of salt. This assumed effect upon the quality of the butter can only be remedied by stopping the use of impure salt. The chief undesirable and impure constituent present in salt is magne- 262 sium chloride. substance in sal BUTTER-MAKING. It is known positively that the presence of this t, even to a small extent, imparts a bitter flavor to butter. Salt containing a large amount of this and other impurities also than does pure salt in use in D absorbs moisture from the air more readily salt. According * to analysis of the best dairy enmark, the composition is as follows: Pure Balin eo Soh co peesemeeiiees- Bue? isa alia ea Ree nN 18 Gypsum. . Eee eT errr nite .05 Sodium sulphate. Spun aum ae Seles 21 Water. . 2.07 100.00 The purest American dairy salt has the following composi- tion: ¢ Pure salt (NaCl). . Lenemmesneee. WO9I8 Magnesium ahlovide, ( ‘MgCl. . Lenadn aes 05 Gypsum (calcium sulphate, Ca80,).... feene pdt Calcium chloride (CaClg)...............-. 19 Insoluble matter....................5005 03 Moistitresy) ce soap reewiaidewa tina Svea 01 100.00 In order to cannot rely on judge the quality of salt the butter-maker the chemical analysis for a detection of im- purities, but must judge the quality from its appearance, flavor, and odor. Good dairy salt does not have a dark-bluish, coarse, granulated appearance, but a clean, white, silky look, and should dissolve quickly. Salt should be kept in a clean dry place free from odor. * Boggild, Maolkeribruget, Denmark. t Bul. No. 74, Wis., by F. W. Woll. SALTING AND WORKING OF BUTTER. 263 Gritty Butter— ‘Gritty butter’’ is a familiar phrase used by expert butter-scorers to indicate that part of the salt is present in an undissolved condition. To most consumers this condition of the salt in butter is objectionable. When properly incorporated, salt should be present in the form of a solution in the butter. The gritty condition of the salt in butter may be due to (1) poor condition of the salt before it is added to the butter; (2) adding so much salt that it cannot be dis- solved by the water in the butter. The maximum amount of salt that butter will dissolve depends upon the amount of moisture present. The maximum amount of moisture per- missible in butter, as limited by law, is 16%. The condition of the water in butter prevents the water from being saturated with salt during the comparatively short time allowed for salt to dissolve during the manufacture of butter. (3) Insufficient working. If the butter is not worked enough to distribute the salt evenly, some portion of the butter will contain more than the other portions. The portion that contains the excess of salt does not have enough moisture to dissolve the salt; while if the salt had been evenly distributed in the butter, all the salt would have been properly dissolved. When gritty butter is caused by insufficient working, it usually mottles. Mottled Butter.—Mottled butter is butter which is uneven in color. This unevenness in color may be due to several different causes. It may be due to specks of curd (speckled butter), and it may be due to certain organisms (dappled butter). These causes of mottled butter are not very com- mon in factories where the manufacture of butter is properly carried on. The most common fault of mottled butter is the improper incorporation of salt and the presence of an excessive amount of buttermilk. Mottled butter caused in this way is com- mon. It would be of much commercial importance if it were possible to prevent its occurrence. In case all the water had been saturated with salt, and there is still undissolved salt left, then the granular or undissolved salt will cause no 264 BUTTER-MAKING. mottles. The most important thing to observe in order to prevent mottles is: (1) to have the buttermilk well washed out; (2) to have the salt thoroughly dissolved; and (3) to have the brine properly distributed. Recent work by Drs. Van Slyke and Hart show that if the proteids are thoroughly washed from the butter, mottles cannot be produced, no matter how unevenly the salt is distributed. Complete removal of the buttermilk by washing is one of the essentials in order to prevent mottles in butter. The mottles caused by improper incorporation of salt assume two different forms, viz., mottles proper, and wavy butter. As has been mentioned before, the mottles result from un- dissolved salt. Whenever there is undissolved granular salt present, the moisture is attracted and the color deepened at that particular place. In case the water has already been saturated with salt, there is no danger of mottles, no matter how much gritty salt is present. Wavy butter is caused by an uneven distribution of the brine. If a little salt is added to the butter and dissolved without working the butter sufficiently, the salt will go into solution in certain portions of the water. This water contain- ing the greatest amount of salt will produce a high color in certain portions of the butter, while the portion containing water with less salt will have a lighter color, thus causing streaks in the butter. In case butter has become mottled on standing, the mottles can be entirely eradicated by reworking the butter. Though some of the moisture is lost during this reworking process, it is usually advisable to rework the butter rather than to place it on the market in a badly mottled condition. The mottles should, however, be prevented rather than cured. This can be done by sufficient working while the butter is in proper condition, and at the proper time. Brine-salting.—Brine-salting is not as a rule practiced in creameries. It is too expensive a method of salting, and also too laborious. By salting butter with brine it is hardly possible SALTING AND WORKING OF BUTTER. 265 to get in salt enough to suit the American butter markets, 2% being about the maximum amount of salt that can be incorporated by the brine method. In some instances, brine-salting has been recommended. If a light mild taste is desired, the brine method may give good results. The greatest advantages of brine-salting are that mottles in butter are practically avoided, and that the over- run is usually increased a trifle. Especially is this so if the temperature of the brine is medium high when added to the butter. In order to get enough salt (2%) into the butter by the brine method, it is necessary to churn it considerably in the brine and to use two sets of brine. When brine is first added the butter already contains considerable water. This water practically has to be replaced by brine. This is difficult to do, especially if the butter has been overchurned a trifle. By churning the butter in the first set of brine, the brine will soon become diluted to such an extent that it will impart but little saltiness to the butter. For this reason this first set of brine should be removed and another one added. Then churn again in this brine. This last set of brine will have very little curd in it, and can be saved until the following day and then used as the first set of brine. This first set of brine may be used each day for soaking tubs. It is essential to leave the brine on the butter for from five to fifteen minutes. Churning excessively in the brine, espe- cially if butter is medium soft, will cause too much water to be incorporated in the butter. After the butter has been ex- posed to the second set of brine the proper length of time, it should be drawn off and the butter worked in the usual manner. Less working is usually given to butter which has been salted by the brine method. It should be worked enough to dis- tribute the brine evenly in the butter, and to bring the butter into a compact form. If the butter salted by the brine method is not worked sufficiently, it will after standing become streaky in color. 266 BUYTER-MAKING. Workinc or Butrer. Objects.—The objects of working butter are: (1) To distribute the salt and brine evenly in the butter. The number of revolutions in the churn necessary to accom- plish this will vary somewhat according to the conditions of the butter, and according to the kind of butter-workers em- ployed. If the butter is of medium firmness, about 12 revolu- tions in the Victor Combined Churn will usually distribute the salt properly, providing the working is well distributed over the working period. It used to be, and is still, the practice in creameries to add the salt while the butter is in a hard granular condition, and then rotate the churn several times in slow gear without putting the workers in gear. This is done in order to mix the salt thoroughly without working. Then it is allowed to stand for five or ten minutes, then worked about four revolu- tions and allowed to stand a little while again, then the working is completed by allowing the churn to revolve four or five times more, or as many as is deemed necessary to bring the butter into proper condition. It has, however, been demonstrated that it is not advisable to add the salt while the butter is in this hard granular form. The butter should be united into larger irregular granules before the salt is added. If the salt is added to the butter in a more or less gathered condition, then the workers should be put in gear at once, for otherwise the salt will be scattered on the inside of the churn. Butter can be worked three or four revolu- tions and then allowed to stand until the salt is almost dissolved, at which time the working can be completed by revolving the churn four or five revolutions more. Some prefer to work a little more than ten revolutions in order to be sure that the salt has been evenly distributed. If the Disbrow churn is being used, it is necessary to work the butter a greater number of revolutions than that recom- mended when the Victor churn is used. In the Victor churn SALTING AND WORKING OF BUTTER. 267 the butter is virtually worked twice at every revolution, while in the Disbrow churn the butter is only worked once for about three-quarters of a revolution. From sixteen to twenty revolu- tions of the Disbrow churn usually mixes the salt with the butter properly. It is impossible to state exactly the number of revo- lutions butter should be worked, as it varies according to differ- ent conditions. (2) Working the butter is done in order to bring it into a compact form. When butter is soft it usually gathers, but ttn NT Fic. 156.—The table butter-worker. if it is present in the firm granular condition, which condition results from churning thin cream and washing the butter in cold water, it is more or less difficult to get the little granules together. More workjng is necessary when the butter is in such a condition. (3) The working of butter is also done in order to express an excessive amount of buttermilk or water. By adding salt 268 BUTTER-MAKING. and then working the butter, the excess of buttermilk is largely eliminated. Especially is this so when the butter isin a medium firm condition. Working is also effective in removing water from the butter. In the manufacture of process butter, excessive working while the butter is in a firm condition is now resorted to. Before the national law, which limits the moisture-content of butter to 16%, went into effect, process butter usually con-: tained more than 16% water; but now the moisture-content of this kind of butter is largely controlled by working it in the absence of water while it is in a firm condition. CHAPTER XVIII. PACKING AND MARKETING BUTTER. Kind of Package to Use.—For creamery purposes the 60- pound ash tubs are customarily used. The package, of course, varies according to different markets. In case that butter is made on a small scale, such as on the farm, earthen crocks give good satisfaction. There is no other package that gives so good results as the earthen jars, when viewed from a stand- point of good keeping quality of the butter. The objec- tion to earthen jars or crocks is that they are heavy and easily broken during transportation. It is undoubtedly on this account that earthenware is not used more for the packing of butter. There are two kinds of tubs chiefly used in creameries, viz., the ash tub, and the spruce tubs. These tubs are made in different sizes, 10-lb., 20-lb., 30-lb., and 60-lb. The 60-Ib. ash tub is used nearly altogether in creameries that pack butter on a large scale. When smaller amounts of butter are being packed, usually the smaller spruce tubs are employed. Square boxes are used also to some extent. They are used more in some of the Eastern States, but very little in the West and Central West. During the fall and winter when the milk-supply is rather low, many creameries print all the butter. Most of the com- mission firms will pay about a cent more per pound for butter when it is put up in pound prints and wrapped neatly in parch- ment paper. The wrapper should bear the name of the manu- facturer or the name of the creamery. If the quality of the 269 OLZ ‘uby ‘eyodoy “og Arowvaty peyUOUTJUOD) *41999Nq BuTyoed puv SurumMyO—'2GT “Ol ie PACKING AND MARKETING BUTTER. 271 butter is good, it will take but a short time for the consumers to become familiar with that particular brand. It is essential, however, to consider the cost of printing the butter and the losses in printing. Some little waste of butter accompanies the printing process. Besides this, if the butter is firm, as it usually is in order to have the prints assume the proper shape, there is a loss of some moisture. Preparation of Tubs.—If tubs are stored in a damp room, they are likely to mould in a short time. Occasionally tubs are in a mouldy condition when they come from the factory or creamery supply-house. The mould that forms on the inside of the tub when standing in a damp place is very conspicuous. In many instances the tubs are also cracked. This is due chiefly to the tubs becoming dry, and in some instances is due to the use of imperfect material in the manufacture of the tub. Butter-tubs should not be made from damp, unseasoned, and partly decayed wood, as they are likely to impart to the butter more of the woody odors than do those made from sound, well-matured wood. In order to kill all the moulds which may be present in the tub, and to close the cracks, so as to make the tub practically air-tight, it is essential that the tub should undergo some process of preparation before the butter is packed into it. There is a single substance which will destroy the germs, moulds, and also close smaller openings in the tubs, viz., a saturated solution of brine. As a rule this gives good results. The day previous to the packing of the butter, the tubs should be filled with satu- rated brine, and allowed to stand and soak until the following day. The paper-linings and circles should also be soaked in the same brine before they are used. It is a good plan to have the brine lukewarm, although cold brine will answer the pur- pose. Just previous to using, pour out the brine, wash the tubs thoroughly, then scald them, by putting them into scalding- hot water or over a steam-jet. Cool off the tubs by filling them with cold water; when cooled, pour out the water, line them, and they are ready for use. The covers should be on while they 272 BUTTER-MAKING. are soaking. This prevents the tubs from warping and getting out of shape. By soaking the tubs in brine and scalding as above, if thoroughly done, there is little danger of getting moulds in the butter. Some recommend the soaking of the tubs in brine only, without scalding; others recommend the scalding without soaking in brine. The chief difficulty with scalding the tubs Fic. 158.—Elgin style butter- Fic. 159.—Bradley tub. butter-boxes. * without soaking is that when wooden tubs are exposed to such sudden heat they usually warp. The hoops are also likely to burst, and if this method is employed alone, many of the tubs will be rendered valueless owing to the bursting of the hoops. If the tub is gradually soaked in brine first, heat may be applied afterwards with little or no injury to the tub. Owing to the many complaints of mouldy butter, especially during the summer, several other methods of preparing tubs have been recommended. In following out the above method many makers PACKING AND MARKETING BUTTER. 273 omit to use concentrated brine. If the brine is weak, then, of course, it will have little or no effect upon the moulds; but if the brine is saturated, the wood will become saturated with brine and prevent the growth of mould during the trans- portation of the butter. Moulds usually start to grow on the inside of the tub, next to the butter. Some of the other methods recommended for the prepara- tion of tubs are: (1) Paraffining. This is accomplished by melting the paraffin, then using a soft brush with which to spread the liquid paraffin all over the inside of the tub. After the liquid paraffin has been applied and cooled, it will solidify, and a thin layer of paraffin will cover the inside of the tub. (2) The second method is to soak the tubs in brine containing from 2% to 3% of formalin (40% formaldehyde solution); about three ounces of formalin to each gallon of brine is about the proper proportion. Special efforts should be made towards having the package appear as neat as possible. They should be clean, and the cover should fit well. After the tub has been washed, lined, and otherwise prepared, it should be weighed, and the weight of the tub marked on the outside. Packing of Butter.—The packing of butter should be con- ducted under as favorable conditions as possible. Before nak- ing use of the butter-ladles they should be scalded and then cooled off in cold water. This prevents the butter from sticking to them, and also cleanses them from dust and germs which may have lodged on them. When the butter is being transferred from the churn into the tub, it should be firmly packed. That is, there should be no holes near the bottom and sides of the butter in the tub. When the butter arrives on the market it is sometimes turned out of the tub (stripped). If it has not been firmly packed, the butter will be filled with holes on the sides and show an unattractive appearance. Besides this, if there are any holes in the butter, the moisture and air will gather there. This gathered brine at time causes a change in color on the surface of the butter to which the brine was 274 BUTTER-MAKING. exposed. The tubs should be well filled. Any open spaces left in the butter permit the circulation of air, and the butter is more likely to absorb the woody odors from the tub. Open. Folded. Fic. 160.—The Eureka butter- Fic. 161.—Butter cartons. printer. In the preparation of the tubs, many of these woody odors are eliminated, but it is impossible to remove all of them. The heat when applied to the tub opens up the pores of the wood and causes the volatile woody odors to pass off with the escaping steam. When the wood is removed from the influence of the steam, the pores again close, or contract, and in that way most of the woody odors are removed, at least from the inner surface of the tub. The remaining woody odors should not be allowed to circulate inwardly through the butter by allowing empty spaces inside the tub. The top surface of the butter can be made to appear smooth and full by filling the tub a little more than full of butter, and then cutting the excessive amount of butter off with a string. The extra butter can then be rolled off, and the top appear perfectly smooth and full. PACKING AND MARKETING BUTTER. 275 The surface of the tubs should be neatly finished by pleating the lining of the tub over onto the top of the butter. The lining should not be allowed to lap over any more than about an inch. A cloth circle should then be neatly put on. A Fic. 162.—Tub-fasteners; common tins. handful of salt sprinkled on the top of this circle is advisable. A little water may be sprinkled on to cause the salt to become wet. Some butter-makers prefer an additional paper circle on top of the salt again. Fic. 163.—Tub-fasteners; tin and tack combined. Packing Butter for Exhibition Purposes.—-In case butter is to be opened and scored several times, it is advisable to use paper circles instead of cloth circles. Cloth circles give a much better appearance when the tubs are not to be opened often, but they Fic. 164.—Tub-fasteners; riveted. are difficult to readjust after they have been taken out of posi tion, while the paper circle can be taken off and replaced as often as desired. This applies especially to butter entered for scoring contests, where the keeping quality of butter has to be tested also. Twenty-pound ash tubs are generally used for exhibition purposes. Ash tubs take a little better finish 276 BUTTER-MAKING. than do spruce tubs. Sandpapering the tubs on the outside gives a nice appearance. A fine-appearing tub may count con- siderably when the final decision is rendered. In order to keep the tub in a clean and good condition during transit special precautions should be taken by the sender. A good way of preparing a tub is to tack the address on the cover, wrap the tub well in paper, and fasten the paper by wrapping a string around the tub a few times. Drive no more nails in the tub than is necessary. Three tins are sufficient to fasten the cover to the tub. The tin fasteners should be placed equal distances apart. After the paper has been wrapped around Fic. 165.—The Lafayette lever butter-printer. the tub the whole should be burlapped. These burlaps can be obtained with the tubs from any of the creamery supply- houses. The tub should then be labeled, and it is ready for shipment. Another good way of preparing a tub for shipment is to pack the 20-pound tub into a 60-pound tub. Fill the space between the small and the large tub with paper. This is con- sidered by many to be the best method of shipping butter for contests, as the paper, packed in on the sides of the tub, pre- vents the heat from penetrating. In cold weather it also pre- vents the butter from freezing, at least in a measure. Storing Butter in Creameries.—The temperature of the room in which the butter is being stored should be as low as conditions will permit. A temperature of 50° F. or below is favorable to the keeping quality of the butter. Usually the PACKING AND MARKETING BUTTER. aie butter is kept at the creamery for from half a week to a whole week. It is advisable to ship as often as is considered con- sistent with the amounts of butter handled. The refrigerator in which the butter is kept at the creamery should be kept as pure and dry as possible. Damp places are always con- ducive to the growth of germs, especially moulds. Vegetables or foods of other kinds should not be allowed in the refrigerator Fic. 166.—The engine-room of Littleton Creamery Co. (Creamery Journal.) with the butter, as they are likely to impart foreign flavors to the butter. Mechanical refrigeration and cooling with ice are the best cooling facilities. In case it should happen that it is impossible to obtain ice, water can be utilized for this purpose. The water used in the creamery can be made to run through a galvanized-iron tank. This tank is properly placed in the butter storing-room, or refrigerator, so as to allow as much cooling-surface in the butter-room as possible. This method 278 BUTTER-MAKING. will not coo) the room as effectively as ice, but in the absence of ice this is better than no cooling at all. Cost of Producing One Pound of Butter.—The cost of pro- ducing a pound of butter varies at different creameries. Up to a certain limit, the more butter that is being produced at yy Dead Air Space Row of Tile Outlets Fig. 167.—Cross-section of a sewage-disposal tank. (Wallace’s Farmer.) one place the less will be the cost of production, that is, pro- viding the creameries are otherwise equally well managed. The Iowa State Dairy Commissioner has investigated this Ground Line Vent = m Waste Water from Cream Vats and Starter Can => ae | f ] 9 Manhole =) I 2 | é £ | 4\|I A°* (=) rd Fie. 168.—Septic tank for creamery sewage disposal. (By Prof. J. Michels.) The tank should be located in the ground with the top within a foot or two of the surface. It may be constructed of planks. Brick, stone, or concrete is preferable for durability. The tank should be built air- tight except in two places, D and E. > ry & 6 ry o \ Discharge: question and finds that the cost of production varies from 1.2 cents to 6 cents per pound. According to the reports sub- mitted to the office of the State Dairy Commissioner, the highest cost of production comes from a co-operative creamery that makes a little less than 30,000 pounds of butter per year. The lowest cost of production is submitted by a co-operative 279 PACKING AND MARKETING BUTTER. a a fy a a km pe ere ep ee oe 624--———---—--——~—---—-—----—-—-—--~—~—---- LTT LS OFFICE MILK RECEIVING 7'6x WW’ ROOM MAKE rf 76x 66" a is} Pa 2 ——a a STORE ROOM * ee er) GUTTER Z a? , | 73x11 \ é aoe a ° el Ra N R COLD STORAGE eee A 23'x 309° 79x11" PLATFORM 4'x 12’ Fie. 169.—Plan of a creamery. Scale, 3/’"=1’. Floor plan. (Bul. 53, Montana.) 2 SLOPE FLOOR PLAN 2 SLOPE BOILER 1 \ ! ! | | | | | | L meee POWER ROOM 2 SLOPE 12'x 23' FUEL ROOM , 6X 23 a {-----——-—-- 4 | eer 280 BUTTER-MAKING. creamery making nearly half a million pounds of butter from whole milk exclusively. The approximate average cost of mak- ing butter for the whole State of Iowa in the whole-milk cream- eries is about 2} cents per pound. As the creameries produce on an average about 150,000 pounds of butter per year, the running expenses of the average creamery are approximately $2350.00 per year. The following table will show the variation in cost of pro- duction per pound of butter: Class. Creamery Cost of Manufacturing a Pound of Butter. a d ae 1 | Creameries making no more than 50,000 lbs. of Ut Cer 5 255 siiscdestesaseyaveynssi dual eovouabesarPianein, eleipaoke enveas 44 3.14 2 |Creameries making between 50,000 and 100,000 Ibs, Of BUGbER 65 ees es tag e-e 2 cea eee ang econ s 98 2.36 3 | Creameries making between 100,000 and 150,000 Ibs: of butters. 42.24 20% ss s.ceas toe cs eee awe 56 1.99 4 |Creameries making between 150,000 and 200,000 IbsOF Dubter’s 6 coc oye es ee tached emdoa sais 28 1.78 5 | Creameries making between 200,000 and 300,000 Tbss Of DUttEE socio es gis Dose deb ee alain ceeeies 27 1.71 Average for the State............0c cece ee eeees 253 2.28 Average for classes 2 and 3..............-.++.. 154 2.22 CHAPTER XIX. COMPOSITION OF BUTTER. Butrer is composed of fat, water, proteids, milk-sugar, ash, and salt. The milk-sugar and ash are present in butter only to a very small extent. In the analysis of butter the milk-sugar is usually included with the proteids (curd), and the ash is reckoned in with the salt. Storch gives the following average composition of butter: From From Fresh Cream. Ripened Cream. Wales cave oneussca eaaws 83.75 82.97 WHET cies ween en egecenenss 13.03 13.78 Proteids (curd)............. .64 84 Milk-sugar................. 385 .39 NGM bisa eae palsies Gslaestanees 14 16 Balt. scwcwsvewaewaieen nas 2.09 1.86 The average composition of butter as determined from the analysis of 221 samples, representing 55 different creameries in different parts of the State of Iowa, is as follows: Ta Gis 2 dos our hata aren toae oranee ars 84 Water jcexiis caus aiseratinencleas Gee eens aan 12.73 CID ais: cate ae esas Sea ele BS ALOR eae ee OSES es 1.30 Daltand AShy.c sch atnrpon Wa ween eae 1.97 EFFect oF Composition oF Burrer Uron QUALITY. The quality of cream or milk from which the butter has been produced and the methods employed in the manufacture have more effect upon the quality of butter than has the composi- 281 282 BUTTER-MAKING. tion. A small variation in the components of butter affects the quality very little, provided the butter has been properly made, and the components properly incorporated. In the same creamery the composition of butter varies according to the season of the year, from day to day, and even from one churning to another. According to the present methods of manufacture, water, salt, and fat are the components most likely to vary. Casein varies very little. Curd and Sugar.—Occasionally the curd-content may go as high as 4%. It rarely exceeds 2%, and seldom falls below .5 of 1%. A high curd-content will show itself in the butter in the form of a milky brine, or in the form of white specks. If there is less than 2% 0” curd present in the butter, the brine shows no noticeable milkiness. More than that much curd can, as a rule, be detected from the color of the brine. If the casein or the curd has been incorporated in the form of small lumps or specks, then abnormal amounts of curd appear. When the sample of butter is taken for analysis, such a speck of curd present in the sample raises the final curd-con- tent to a comparatively high figure. As has been mentioned before, the curd and milk-sugar are incorporated from the buttermilk into the butter during the churning. In manufacturing butter for storage, these sub- stances should be excluded from the butter as thoroughly as possible. The milk-sugar and albuminoids constitute the chief food for bacterial growth. As the deterioration of butter has been demonstrated to be due chiefly to the action of organisms, it becomes essential to restrain their growth as much as possible by excluding food necessary for their growth. Salt.—In the chapter discussing the salting of butter, it was mentioned that a small increase or decrease in the salt-content of butter can be recognized by most consumers, while the same variation in the other constituents cannot be noticed so easily. The average salt-content of butter is about 2%. As the amount of salt properly dissolved in butter depends upon the amount of water present, the first important step in controlling the salt- COMPOSITION OF BUTTER, 283 content is to have reasonable control of the water-content of the butter. If there is no more than 16% of water present in the butter, it is desirable to have as much salt in as the water will dissolve within the time usually allotted for that purpose. This much salt suits most of the American butter markets. The authors have analyzed commercial butter containing more than 8% salt. The major portion of this was present in an undissolved condition. Such butter is called gritty, and is ob- jected to by most consumers. Salt acts as a preservative and adds flavor to the butter, provided it is in good condition. It is said that the addition of salt has some effects upon the body of the butter. Richmond asserts that salty butter loses more water on standing than unsalted butter. This is undoubt- edly due to the leaky condition which is brought about when salt is added to butter while in a granular condition. Salt attracts moisture. Unsalted butter would not be exposed to this influence of the salt. When kept unsalted, butter usually becomes cheesy in flavor in a short time, while salted butter assumes entirely different characteristics. Water.—The moisture-content of butter may vary between 6% and 16%. Frequently butter is found that contains more than 16%, but this amount is in violation of the law. Butter may contain as much as 18% of water, if properly incorporated, without affecting its apparent commercial quality. Water is present in a greater proportion than any other non-fat con- stituent. Its variation is also greater than that of any other constituent. The fat will, of course, vary with the water. The more water there is present in the butter, the less fat there will be, and the less water, the more fat. As butter is bought Fig. 170.—Ice-crusher. 284 BUTTER-MAKING. with the understanding that it is rich in fat, much objection has been raised to butter containing an abnormal amount of water. This objection by consumers is, of course, a just one. The producers desire to incorporate as much water as is consistent with good quality. Butter containing a high moisture-con- tent, more than 18%, will appear dead and dull. It is sticky, and when sampled with a trier it is next to impossible to draw a full trier of butter. It shrivels and rolls on both sides of the trier’ Moisture affects butter in two principal ways, according to the way in which is is incorporated: (1) By causing leaky butter, and (2) by making the butter appear dull. 1. This leaky condition in commercial butter is very common. It has been a common opinion among butter-judges that when- ever water appears in large drops on the butter, and some- what slushy when sampled, the butter contains too much moisture. This, however, is not always the case, as butter will not as a rule hold an excessive amount of moisture in that form. Even if this leaky butter does not contain an excess of moisture, it is a very undesirable condition, as most consumers object to this apparent slushiness. As has been stated before, this leaky condition is brought about chiefly by churning the butter to small granules, washing the butter very little in cold water, salting heavily, while butter granules are still small and firm, and working the butter frequently in the presence of brine. When moisture is properly incorporated in butter, it should be present in exceedingly minute drops. In a fine state of division it will not escape from the butter. This leaky condition of moisture in butter may give a wrong impression to consumers about its moisture-content. Major Alvord, Chief of Dairy Division of U. S. Department of Agri- culture, reports that a great many buyers on the English market have the opinion that American butter contains an excess of moisture. This conclusion evidently has been reached on account of the water in American butter often appearing in this leaky condition, as described above. In reality it is low in its moisture-content. COMPOSITION OF BUTTER. 285 2. The dull and dry appearing condition of butter may be due (1) to the presence of an excess of moisture properly incor- porated; (2) to the treatment the butter receives during manu- facture. When the dull and dry appearance is due to moisture, the water has been incorporated during the churning, or during the washing process, through excessive churning or working Fic. 171.—Rubber mop. in the buttermilk or wash-water at a high temperature. The dullness may also be brought about by overworking the butter. If the butter has been overworked, as a rule, it contains little moisture, though its appearance may be like that of butter containing an excess. The conditions which affect the moisture-content of butter during its manufacture are: (1) Temperature of cream and of wash-water. The higher the temperature of these two substances, the more water will be incorporated in the butter. When the temperature is too high, the body of the butter is injured materially. The keeping quality of the butter is also injured by having the temperature of the cream too high. The buttermilk constituents are incor- porated with the butter and cause it to deteriorate rapidly. (2) The amount of churning in buttermilk and wash-water. The more the butter is being churned or worked in the presence of moisture, the more water the butter will contain. When the temperature of buttermilk and wash-water is low, a small amount of churning affects the moisture-content very little, while if the temperature is high, great care should be taken not to overchurn. (3) Per cent of fat in cream. The thicker the cream the more moisture there will be present in the butter. In order to 286 BUTTER-MAKING. churn thick cream, a higher temperature is necessary. It is difficult to stop the churn without overchurning a trifle. These two conditions, thick cream and high temperature, are both conducive to a higher moisture-content. (4) Amount of work the butter receives. If the butter is in a moderately firm condition, the more the butter is worked, in the absence of water, the less moisture it will contain. If the moisture is present in a leaky form as mentioned above, it is expelled to a great extent by working. But if the moisture is properly incorporated and the butter is not too firm, work- ing has little effect upon changing the moisture-content of the butter, providing there is no water present in the churn. Several other factors, such as pasteurization of cream, full- ness of churn, and character of fat in cream, all have a small influence in governing the moisture-content of butter, but in this summary it is sufficient to say that temperature, degree of churning, and thickness of cream are the only conditions which materially influence the moisture-content. If churning is carried on to an excess, whether it be in the buttermilk or in the wash-water, all other factors are subordinate and have little or no influence in regulating the moisture-content of butter. Low temperature is the chief factor that delays in- corporation of moisture in excessive churning. Fat—The English, the German, and the United States governments have endeavored to protect consumers in regard to the amount of nutriment in butter, by recommending 16% of water as a maximum limit. Such a ruling has worked suc- cessfully now fer several years. Efforts have recently been made in the United States to base by law the nutritive quality of butter upon a certain minimum percentage of fat. The minimum amount of fat recommended by the appointed com- mittee of chemists is 82}%. A minimum standard of 824% of fat in butter would be unintentionally violated, while a basis of 80% fat in butter would be more consistent with the quality of butter as manufactured. CHAPTER XX. JUDGING AND GRADING BUTTER. Butrer may be judged from a commercial and from an individual standpoint. Individual judgments of the same butter may vary considerably. It is important that the judge should become familiar with the quality of butter as required by our standard markets, and then judge the butter according to the demands of the mass of the consumers, rather than according to personal likes and dislikes. In order to become a good butter-judge, it is essential that the senses of taste and smell be acute. Even if one’s taste and smell are keen and sensi- tive, considerable practice or experience is necessary. Almost any one can tell a good sample of butter from a very poor one, but when it comes to differentiate between two samples which are nearly alike in quality, skill and experience are required. The chief thing in scoring butter is to become thoroughly familiar with the ideal flavor of butter; then by repeated comparisons of different samples of butter to this one ideal flavor, one will soon become efficient in grading the butter. Standard for Judging.—In America the distinct qualities which are noticed in butter are designated according to the basis of points given below. It will be noticed that different values are given to the different characteristics, according to their relative importance. The score-card given below is used commercially, and is based upon 100 as perfect: ScorE-caRD. : Perfect. Score. Remarks. PlavOtiacaess Gey es eeees omy eve BG > eagle Bo Venta cesae es nae Gia Bod y'.5 seca nsicied senaas ae Sh ge QB Sarasa) - ad heard came esnaeiats COMO es cseeais ccanliw we ereans 15 oS ebahtan ase as Seva teda-saiebes Salts ede sckes React x ean wSrev eo ravens 10. weaee Bees varnd ys Soe ee Medes Style:d aviiegrie saad siee thaw Rr tsheatinek Givemnennels wane as aries t Totals. ..iccsaswicwew new JOO: -.ieevinead Geetha ceed Dates icsee ccc tras eae ssee e434 Scored: DY isi wes sieeve gine eeseas 288 BUTTER-MAKING. At a recent conference of the Société Nationale de Laiterie, held at Brussels, the following scale of points was suggested for butter (Creamery Journal) : OOF: jon asa be nearer fi Niclaenta mate damtdeten Aas 5 mee ieuyg@ner ans wens s oe: 5 eflection................. 10 Work. .......+5 Cleanliness................. 5 Chemical analysis........... 10 Firm ness:-3.2 tea eedos ed eels 13 Consistency.... . ; Spreading facility........... 12 } Interior structure........... 5 Purttycas.cc ssa dees s ge va viers 5 TRB. a5. 3s en nite | Taste and aroma,.......... 30 100 ScorE-cARD USED BY W. S. Moors & Co., Cuicaco. Stenellccs gage wedeesacerss ee Date.......- £6) 220 01 (-) an ee Et Buttermakere city segicas Gouge se sieeiedes Too high acid.................--.-- I-Site ccee oo Sales Paes SOUMs ictus vicars ging a aattie-s oaieioee dae VeB eine aaa eek cae tee se Heated oy .ssavceae ays dees venareeee Qi iiacstaiawrietracisans: Cbiicaae oe Weedyinsccddes teersaveessteeseds P10 sas oc eesatiee. sees Bees Manted, cco. sisic scscasetonsiasseveae ee ate o% Qi bet Aeeea Hee Sif sEReRs sows BAIT sec esol bckcy nisin Be Ganale eases SS" Q1Os sais ieiehesawane Raheem Poor sewerage, dirty cans, etc........ DAL c.sseutantrm ames «bivapnalsieicys Wintery. ocecacias ete gsc eeeee se eeu QAO nara eee eupge mos 6 | Old milk... .........-2-0000 eee eee Dats wasiacarpaceaienan: —aoihnadeandiss i Mlabiselersesnaycea sic icuetay coms ots lB pccsiserawdcs! Gas eeeeess | Laight: «.c.meas enews teatee i eenees es LS e ee coer? Svataoceek SUMMECLY sig sk eee eee eee eee es He IO. nciseneeevens aeve sieeve yess i aaeges se eux oes Sea ROD AE TES Be 220 length of time to carry. .......0.0. 000020 eee eee ee 222 over-ripening and under-ripening of................-........ 223 Preparation! Of... ceed saamedia es ewhend de tage gee tows 217,214 Sugar and curd in butter............. 0.0... Be elated 282 IMMA Ky s osises ke vs ese Snalee ete ptela earahgih ep umdiia ues! aan en cong @retes ac 16 Streaked! butter: vc: Qe 84 Tests, f6erMentatiOn oiecins.c.c0tees 6.4 yas ee pldy eu nea ¥ eoee Yeo Gu ee e 81 pasteunzed milks ss sige e oyein e o4 SENS 53 Gs Oh aneek cae a dnmla’e dev 42 Total solids of milk, variation of... ......... 0c. cece cee eecececaee 3 Tubs, preparation and kinds of. ......... 0.0... c cece cece eee eeeeees 271 Udder, external appearance of. .........0.0. 0. ccc cece cece eceeeceuces 29 internal structure Of.,.......... 0.0000 ccc cece cece ec ccceeeewe 22 Unorganized ferments:. <2 cscs cad eens sae et gee bs tee ee Rese es 44 eee Ta NS sec. Brest 6. 3 esssd Si NS ovead eden nid as SoG Sk a ced eS a bev aes 20 Utensils, clearings ic iec sis: oe 'sieteo sie sie oe sieve sis ae gees Fe ehans ales Saba s 145, 159 Variation of fat in milk, causes of. .........- 2... cece eee reece ween 63 ViSCOPEN:, WEE? Obs gio eae: ar sted Sod Rees’ m Reader bre bolsio see Gens paws aueee wareAr Ow 39 Viscosity of milky a soc-nccwinas toe tues mae ak ew Wha Swe eea ees 37 restoration OF 6:56 ce.sanare selenite Shwe sank APRS RES S 39 Volatile fata.cies2saescaens genes vee det Ae ES ee ae Pee Seed eee ed nee ss 11 Washing butter, kind of wash-water for. 2.0... cece cere eee teenies 248 PULpaserOl, hsicss Kacey Cama ems eee o Hee Vangie ves 247 Water in bitters. s vse sees sd aati cu Had owed eh gee ada es 6 Fe uele oa 241 CONGICION LOL. chev sedisigng. outed ds ee Soe camaanawisey SS auese-S Saad Os 242 Water, in relation to salt in butter... ......... 0. ee eee eee eee rece 259 methods of purifying. .........0 066 e cece ence eee eeeneee 250 Wisconsin curd test... 0... . cece ee cece cece tenet een eeeeeseee 81 Working of butter, objects and effects Of... 0.6.0.0... 0 ee ee eee e eee enee 266 Since they were first put on the market, years ago, the U. S. CREAM SEPARATORS have been constantly improved and have always stood before the dairy public as pre-eminently the best cream separator in every essential point. The superiority of their skimming has been repeatedly demon- strated, and at the Pan American Exposition in 1901 the U. S. established the WORLD’S RECORD FOR CLEAN SKIMMING, by leaving only .0138% butter-fat in the skim-milk as the average for 50 separate, consecutive runs— 25% less loss of butter-fat by the U.S. than by any competitor. At the Lewis and Clark Exposi- tion, Portland, Ore., 1905, the U. S. SEPARATOR lowered this record to .0126% as a three days’ composite test of the separated milk from all the cows of all the dairy herds at the Exposition. U. S. SEPARATORS are made by a company which for over 32 years has devoted itself to manufacturing the highest grade apparatus. The U. S. SEPARATOR to-day is the result of many years of experience and progress. In consequence the U. S. SEPARATORS ARE BETTER BUILT than any others, and so last much longer and still do the best work. Thousands of satisfied users testify to this. Write for a handsome catalogue containing some of their letters and fully describing the construction of the U. S. SEPARATORS. VERMONT FARM MACHINE CO., BELLOWS FALLS, VT. 18 centrally located distributing warehouses throughout U. S. and Canada. IOWA DAIRY SEPARATORS are built under patents owned by this company. The patents cover the broad right to narrow the strata of milk in the blue milk zone and to widen the strata toward the center of the bowl where the butter fat is denser. The result of this form of construction permits the skimming of low-tem- perature milk practically as clean as at normal temperatures, and so controls the currents as to absolutely preclude the clogging of the separator bowl. To know how close a separator can be made to skim under adverse conditions is learned practically only by trying out an IOWA MACHINE. It is impossible longer to have any competing tests between the IOWA and other machines, because all separator men know that as a close skimmer the IOWA is in a class by itself. We will be pleased to furnish an IOWA MACHINE for a competing test with any other separator to enable you to know the truth of our claims. If you are buying cream separators or recommending them, don’t you think in all honor that you should know for yourself the com- parative skimming efficiency of the different separators? Why not test them out? We will furnish the IOWA to set in” against other machines. IOWA DAIRY SEPARATOR CO., WatTERLOO, Iowa. That’s what every man is in business for—profit. The use of a cream separator is becoming general among pro- gressive farmers and dairymen. It is no longer a question of whether a cream separator will be a profitable investment, but rather ‘‘ which separator will best meet the requirements of the dairyman ?’’ The Cream Harvester sets a Standard of Excellence. It is light-running, simple and durable in construction, has large capacity, and skims close. There are many other excellent features about the Cream Harvester which are set forth in our Cream Separator booklet. Write for one. INTERNATIONAL HARVESTER COMPANY OF AMERICA ¢ (Incorporated) CHICAGO, - = ILLINOIS BOOKS FOR FARMERS AND DAIRYMEN PUBLISHED BY JOHN WILEY & SONS. ‘THE PRINCIPLES OF ANIMAL NUTRITION. With Special Reference to the Nutrition of Farm Animals, By Henry Prentiss Armsby, Ph.D., Director of the Pennsylvania State College Agricultural Experiment Station; Expert in Animal Nutrition, United States Department of Agriculture. 8vo, vii +614 pages, Cloth, $4.00. MANUAL OF CATTLE-FEEDING. A Treatise on the Laws of Animal Nutrition and the Chemistry of Feeding-stuffs in their Application to the Feeding of Farm-animals. With Illustrations and an Appendix of Useful Tabies. By Henry P. Armsby, Ph.D., Director of the Pennsylvania State College Agricultural Experiment Station. 12mo, x + 526 pages. Cloth, $1.75. A HANDBOOK FOR FARMERS AND DAIRYMEN. By F. W. Woll, Assistant Professor of Agricultural Chemistry, University of Wis- consin, With the Assistance of well-known specialists. Third Edition, Revised. 16mo, xv + 438 pages, illustrated, Cloth, $1.50. THE PRINCIPLES OF MODERN DAIRY PRACTICE, From a Bacteriological Point of View. By Gésta Grotenfelt, President Mustiala Agricultural College, Finland. Authorized American Edition by F. W. Woll, Assistant Professor of Agricultural Chemistry, University of Wisconsin, Third Edition, Re- vised. 12mo, vi + 286 pages, 32 figures. Cloth, $2.00. Sg ats es E oe eee ponies ee rene ats fei eet