Main Lib. ASRICITLTTOAL Wfff* THE BOOK OF CHEESE Efje i&ural Eext-Boofe Series EDITED BY L. H. BAILEY Carleton : THE SMALL GRAINS. B. M. Duggar: THE PHYSIOLOGY OF PLANT PRODUCTION. J. F. Duggar: SOUTHERN FIELD CROPS. Gay : BREEDS OF LIVE-STOCK. Gay : PRINCIPLES AND PRACTICE OF JUDGING LIVE-STOCK. Goff: PRINCIPLES OF PLANT CULTURE. Guthrie: BOOK OF BUTTER. Harper: ANIMAL HUSBANDRY FOR SCHOOLS. Harris and Stewart: PRINCIPLES OF AGRON- OMY. Hitchcock : TEXT-BOOK OF GRASSES. Jeffery : TEXT-BOOK OF LAND DRAINAGE. Jordan: FEEDING OF ANIMALS. Revised. Livingston: FIELD CROP PRODUCTION. Lyon: SOILS AND FERTILIZERS. Lyon, Fippin and Buckman : SOILS, THEIR PROPERTIES AND MANAGEMENT. Mann: BEGINNINGS IN AGRICULTURE. Montgomery : THE CORN CROPS. Morgan : FIELD CROPS FOR THE COTTON-BELT. Mumford: THE BREEDING OF ANIMALS. Piper : FORAGE PLANTS AND THEIR CULTURE. Sampson : EFFECTIVE FARMING. Thorn and Fisk : THE BOOK OF CHEESE. Warren : THE ELEMENTS OF AGRICULTURE. Warren : FARM MANAGEMENT. Wheeler: MANURES AND FERTILIZERS. White: PRINCIPLES OF FLORICULTURE. Widtsoe : PRINCIPLES OF IRRIGATION PRAC- TICE. THE BOOK OF CHEESE BY CHARLES TfHOM INVESTIGATOR IN CHEESE, FORMERLY AT CONNECTICUT AGRICULTURAL COLLEGE AND WALTER W. FISK ASSISTANT PROFESSOR OF DAIRY INDUSTRY (CHEESE-MAKING), NEW YORK STATE COLLEGE OF AGRICULTURE AT CORNELL UNIVERSITY Nefo gorfc THE MACMILLAN COMPANY 1918 All rights reserved COPYBIGHT, 1918, BY THE MACMILLAN COMPANY. Set up and electrotyped. Published July, 191? /%^< Cfe/StT (/ibrory) a lain 1 n>. A^ric. Dent. Xcrtoooti J. 8. Cushing Co. — Berwick & Smith Co. Norwood, Mass., U.S.A. PREFACE CERTAIN products we associate with the manufactures of the household, so familiar and of such long standing that we do not think of them as requiring investigation or any special support of science. The older ones of us look back on cheese as an ancient home product; yet the old-fashioned hard strong kind has given place to many named varieties, some of them bearing little resem- blance to the product of the kitchen and the buttery. We have analyzed the processes; discovered micro- organisms that hinder or help; perfected devices and machines; devised tests of many kinds; studied the chemistry ; developed ' markets for standardized com- modities. Here is one of the old established farm in- dustries that within a generation has passed from the housewife and the home-made hand press to highly per- fected factory processes employing skilled service and handling milk by the many tons from whole communi- ties of cows. This is an example of the great changes in agricultural practice. Cheese-making is now a piece of applied science; many students in the colleges are study ing. the subject ; no one would think of undertaking it in the old way : for these reasons this book is written. This book is intended as a guide in the interpretation of the processes of making and handling a series of im- portant varieties of cheese. The kinds here considered are those made commercially in America, or so widely met in the trade that some knowledge of them is neces- 387241 VI PREFACE sary. The relation of cheese to milk and to its production and composition has been presented in so far as required for this purpose. The principles and practices under- lying all cheese-making have been brought together into a chapter on curd-making. A chapter on classification then brings together into synoptical form our knowledge of groups of varieties. These groups are then discussed separately. The problems of factory building, factory organization, buying and testing milk, and the proper marketing of cheese, are briefly discussed. Such a discussion should be useful to the student, to the beginner in cheese-making, as a reference book on many varieties in the hands of makers who specialize in single varieties, and to the housekeeper or teacher of domestic science. The material has been brought to- gether from the experience of the writers, supplemented by free use of the literature in several languages. Stand- ard references to this literature are added in the text. No introduction to the subject of cheese should fail to mention the work of J. H. Monrad, who has recently passed away. Mr. Monrad never collected his material into a single publication, but his contributions to cheese- making information, scattered widely in trade literature over a period of thirty years, form an encyclopedia of the subject. Bulletins of the Agricultural Experiment Stations and United States Department of Agriculture have been quoted extensively, with citation of the sources of the material. Personal assistance from Professor W. A. Stocking and other members of the Dairy Department of Cornell University, and C. F. Doane of the United States Department of Agriculture, is gladly acknowledged. Students cannot learn out of books to make cheese. PREFACE vii They may, however, be aided in understanding the prob- lems from such study. To make cheese successfully they must have intimate personal touch with some person who knows cheese. Sympathetic relations with such a teacher day by day in the cheese-room are essential to suc- cess in making cheese which, at its best, is one of the most attractive of food-products. THE AUTHORS. TABLE OF CONTENTS CHAPTER I PAGES GENERAL STATEMENT ON CHEESE . . . . . 1-4 Nature of cheese, 1 ; Cheese-making as an art, 2 ; Cheese-making as a science, 3 ; Problems in cheese- making, 4 ; History, 5. CHAPTER II THE MILK IN ITS RELATION TO CHEESE . . . 5-28 Factors affecting the quality, 6; Chemical com- position, 7; Factors causing variation in composi- tion, 8; Milk constituents, 9; Water, 10; Fat, 11; Casein, 12; Milk-sugar, 13; Albumin, 14; Ash, 15; Enzymes, 16 ; The flavor of feeds eaten by the cow, 17 ; Absorption of odors, 18 ; Effect of condition of the cow, 19; Bacteria in the milk, 20; Groups of bacteria in milk, 21 ; Acid fermentation of milk, 22 ; Bacterium lactis-acidi group, 23; Colon-aerogenes group, 24; Acid peptonizing group, 25; Bacillus bulgaricus group, 26; Acid cocci or weak acid- producers, 27; Peptonizing organisms, 28; Inert types, 29; Alkali-producing bacteria, 30; Butyric fermenting types, 31 ; Molds and yeasts, 32 ; Bacterial contamination of milk, 33 ; Germicidal effect of milk, 34 ; Sources and control of bacteria in milk, 35 ; The cow, 36; Stable air, 37 ; The milker, 38 ; Utensils, 39; The factory, 40 ; The control of bacteria, 41 ; Fer- mentation test, 42 ; The sediment test, 43. CHAPTER III COAGULATING MATERIALS 29-40 Ferments, 44 ; Nature of rennet, 45 ; Preparation of rennet extract, 46; Pepsin, 47; Chemistry of ix TABLE OF CONTENTS curdling, 48; Use of acid, 49; Robertson's theory, 50 ; Rennet curd, 51 ; Hammarsten's theory, 52 ; Duclaux theory, 53 ; Bang's theory, 54 ; Bosworth's theory, 55. CHAPTER IV LACTIC STARTERS . . ... ' . . . . 41-54 Acidifying organisms, 56; Starter, 57; Natural starter, 58; Commercial starter or pure cultures, 59 ; Manufacturer's directions, 60 ; Selecting milk, 61; Pasteurization, 62; Containers, 63; Adding cultures, 64; Cleanliness, 65; "Mother" starter or startoline, 66; Examining starter, 67; Second day's propagation, 68 ; Preparations of larger amount of starter, 69 ; Amount of mother starter to use, 70 ; Qualities, 71 ; How to carry the mother starter, 72 ; Starter score-cards, 73; Use of starter, 74; The amount of starter to use, 75 ; Starter lot-card, 76. CHAPTER V CURD-MAKING . . 55-80 The composition of the milk, 77 ; Cheese color, 78 ; The acidity factor, 79 ; Acidity of milk when received, 80 ; The acid test, 81 ; Rennet tests, 82 ; Marschall rennet test, 83; Comparison of acid and rennet test, 84 ; Control of acid, 85 ; Acidity and rennet action, 86 ; Acidity and expulsion of the whey, 87 ; Acidity in relation to cheese flavor, 88 ; Acidity in relation to body and texture of cheese, 89; Acidity in relation to cheese color, 90 ; Control of moisture, 91 ; Relation of moisture to manufacture and quality, 92; Relation of moisture to acidity, 93; Setting temperature, 94 ; Strength of coagulating materials, 95; Amount of coagulating materials to use, 96 ; Method of adding rennet, 97 ; The curdling period, 98 ; Cutting or breaking the curd, 99 ; Curd knives, 100; Heating or "cooking," 101; Draining, 102 ; Application to cheese, 103. TABLE OF CONTENTS XI CHAPTER VI CLASSIFICATION . . . . . . Basis of classification, 104; Processed cheeses, 105 ; Whey cheeses, 106 ; Soft and hard cheeses, 107 ; Relation of moisture to classes, 108 ; Relation of heat to classes, 109. PAGES 81-88 CHAPTER VII CHEESES WITH SOUR-MILK FLAVOR .... 89-110 Skim series, 110; Cottage cheese, 111; Household practice, 112; Factory practice, 113; Buttermilk cheese, 114; Neufchatel group, 115; Domestic or American Neufchatel cheeses, 116; The factory, 117; Cans, 118; Draining racks, 119; Cloths, 120; Molding machinery, 121 ; Milk for Neufchatel, 122 ; Starter, 123; Renneting or setting, 124; Draining, 125; Cooling Neufchatel, 126; Pressing, 127; Working and salting Neufchatel, 128 ; Storage, 129 ; Molding, 130; Skimmed-milk Neufchatel, 131; Baker's cheese, 132; Domestic Neufchatel, 133; Partially skim Neufchatel, 134 ; Cream cheese, 135 ; Neufchatel specialties, 136 ; Gervais, 137 ; European forms occasionally imported, 138. CHAPTER VIII SOFT CHEESES RIPENED BY MOLD . . Hand cheese and its allies, 139; Pennsylvania pot cheese, 140 ; Appetitost (Appetite cheese), 141 ; Ripened Neufchatel, French process, 142; The Camembert group, 143 ; Camembert cheese, 144 ; Description of Camembert, 145; Conditions of making and ripening, 146 ; Outline of making pro- cess, 147; Acidity, 148; Ripening the cheese, 149; Composition, 150 ; Factory, 151 ; Economic factors, 152 ; French Brie, 153 ; Coulommiers, 154. 111-133 Xll TABLE OF CONTENTS CHAPTER IX SOFT CHEESES RIPENED BY BACTERIA .... The Isigny group, 155; Raffine", 156; Lieder- . . kranz cheese, 157 ; Limburger cheese, 158 ; The milk, 159; Making the cheese, 160; Draining and salting, 161 ; Ripening, 162 ; Marketing and qualities of Limburger, 163 ; Yield and composition of Lim- burger, 164 ; Miinster cheese, 165. CHAPTER X SEMI-HARD CHEESES . • The green mold group, 166; Roquefort cheese, 167 ; Cow's milk or Fagons Roquefort, 168 ; Outline of making Roquefort, 169; Ripening of Roquefort, 170 ; Gorgonzola, 171 ; Stilton cheese, 172 ; Gex, 173; Bacterially-ripened series, 174; Brick cheese, 175; Making of brick cheese, 176; Ripening brick cheese, 177 ; Qualities of brick cheese, 178 ; Composi- tion and yield, 179 ; Port du Salut cheese, 180. CHAPTER XI THE HARD CHEESES The Danish group, 181 ; The Dutch group, 182 ; Edam cheese, 183; Method of manufacture, 184; Salting and curing Edam, 185; Equipment for making Edam cheese, 186; Qualities and yield of Edam cheese, 187; Gouda cheese, 188; Method of manufacture, 189; Equipment for Gouda cheese, 190; Composition and yield, 191. CHAPTER XII CHEDDAR CHEESE-MAKING The lot-card, 192 ; The milk, 193 ; Ripening the milk, 194; Setting or coagulating, 195; Cutting, 196 ; Heating or "cooking" the curd, 197 ; Removing the whey, 198 ; Hot-iron test, 199 ; Firmness of the curd, 200; Gathering the curd together, 201; PAGES 134-148 149-171 172-183 184-221 TABLE OF CONTENTS xiii Matting or cheddaring, 202 ; Milling the curd, 203 ; Salting, 204; Hooping the curd, 205; Pressing the curd, 206 ; Dressing the cheese, 207 ; Handling over- ripe and gassy milk, 208; Qualities of Cheddar cheese, 209. CHAPTER XIII COMPOSITION AND YIELD OF CHEDDAR CHEESED . . 222-246 Composition of milk, whey and cheese, 210; Relations of fat to casein in normal milk, 211 ; Influence of fat in milk on yield of cheese, 212 ; Fat loss in cheese-making, 213; Effect of bacterial- content of milk on yield of cheese, 214; Factors affecting the moisture-content of Cheddar, 215 ; Variations of the Cheddar process, 216; Cheddar- type cheese from pasteurized milk, 217 ; Club cheese, 218; The stirred-curd or granular process, 219; California Jack cheese, 220; The washed-curd process, 221 ; English dairy cheese, 222 ; Pineapple cheese, 223; Leyden, 224; Cheddar cheese with pimientos, 225; Sage cheese, 226; Skimmed-milk cheese, 227; Full skimmed-milk Cheddar cheese, 228; Half skimmed-milk Cheddar cheese, 229; Yield and qualities of skimmed-milk Cheddar cheese, 230. CHAPTER XIV CHEDDAR CHEESE RIPENING 247-275 Fat, 231; Milk-sugar, 232; The salts, 233; Gases, 234; Casein or proteins, 235; Causes of ripening changes, 236 ; Action of the rennet extract, 237; The action of the bacteria, 238; Conditions affecting the rate of cheese ripening, 239; The length of time, 240 ; The temperature of the curing- room, 241 ; Moisture-content of the cheese, 242 ; The size of the cheese, 243 ; The amount of salt used, 244 ; The amount of rennet extract, 245; The influence of acid, 246 ; Care of the cheese in the curing-room, XIV TABLE OF CONTENTS 247; Evaporation of moisture from the cheese during ripening, 248; Paraffining, 249; Shipping, 250. Defects in Cheddar cheese: Defects in flavor, 251 ; Feedy flavors, 252 ; Acid flavors, 253 ; Sweet or fruity flavors, 254 ; Defects in body and texture, 255; Loose or open texture, 256; Dry body, 25T; Gassy textured cheese, 258; Acidy, pasty or soft body and texture, 259; Defects in color, 260; Defects in finish, 261. Cheddar cheese judging : Secur- ing the sample, 262; How to determine quality, 263 ; Causes of variations in score, 264 ; The score- card, 265. CHAPTER XV THE Swiss AND ITALIAN GROUPS Swiss cheese: The Swiss factory, 266; The milk, 267 ; Rennet extract, 26.8 ; Starter, 269 ; The making process, 270 ; Curing Swiss, 271 ; Block Swiss, 272 ; Shipment, 273; Qualities of Swiss cheese, 274; Composition and yield, 275 ; The Italian group : Parmesan, 276 ; Regianito, 277. CHAPTER XVI MISCELLANEOUS VARIETIES AND BY-PRODUCTS Caciocavallo, 278; Sap sago, 279; Albumin cheese, 280 ; Mysost, Norwegian whey cheese, 281 ; Whey butter, 282. CHAPTER XVII CHEESE FACTORY CONSTRUCTION, EQUIPMENT, ORGANI- ZATION ......... Locating the site, 283 ; The building, 284 ; Heat- ing plant, 285; Curing-rooms, 286; Light, 287; Ventilation, 288; BoHer-room, 289; whey tanks, 290; Store-room, 291; The floors, 292; Arrange- ment of machinery and rooms, 293 ; Arrangements for cleanliness, 294 ; Equipment and supplies list, 295 ; Factory organization, 296. 276-292 293-296 297-310 TABLE OF CONTENTS XV CHAPTER XVIII HISTORY AND DEVELOPMENT OF THE CHEESE INDUSTRY IN AMERICA ..... . The factory system, 297 ; Introduction of factory system in Canada, 298 ; Introduction of cheddaring, 299; Introduction of Swiss and Limburger, 300; Number and distribution of cheese factories, 301 ; Total production of cheese in the United States, 302; Rank of the leading cheese-producing states, 303; Exportation and importation of cheese by*the United States, 304 ; Average yearly price of cheese, 305; Canadian cheese statistics, 306; Introduction of cheese-making into new regions, 307. 311-326 CHAPTER XIX TESTING The fat test, 308 ; Sampling the milk, 309 ; Adding the acid, 310; Centrifuging, 311; Reading the test, 312; testing whey for fat, 313; testing cheese for fat, 314; Reading the test, 315; The Hart casein test, 316; Solids in the milk, 317; the lactometer, 318; Calculating the solids not fat in the milk, 319; Testing cheese for moisture, 320. 327-342 CHAPTER XX MARKETING 343-361 Buying milk, 321 ; Cheese yield basis of buying milk, 322; Fat basis for payment of milk, 323; Weight basis or pooling method for payment of milk, 324 ; Fat-plus-two method for payment of milk, 325; Comparison of methods, 326; Laws governing the production and sale of milk, 327; Marketing of cheese, 328; Mercantile exchanges, 329; Marketing perishable varieties, 330; Dis- tribution of price, 331 ; Standards, 332 ; Laws relating to cheese marketing, 333 . xvi TABLE OF CONTENTS CHAPTER XXI PAGES CHEESE IN THE HOUSEHOLD ...'.. 362-381 Food value of cheese, 334 ; Digestibility of cheese, 335; Cheese flavor, 336; Relation to health, 337; Cheese poisoning, 338; Proper place in the diet, 339; Care of cheese, 340; Food value and price, 341 ; Methods and recipes for using cheese, 342. THE BOOK OF CHEESE * THE BOOK OF CHEESE CHAPTER I GENERAL STATEMENT ON CHEESE CHEESE is a solid or semi-solid protein food product manufactured from milk. Its solidity depends on the curdling or coagulation of part or all of the protein and the expulsion of the watery part or whey. The coag- ulum or curd so formed incloses part of the milk-serum (technically whey) or watery portion of the iftilk, part of the salts, part or all of the fat, and an aliquot part of the milk-sugar. The loss in manufacture includes a small fraction of the protein and fat, the larger propor- tion of the water, salts and milk-sugar. 1. Nature of cheese. — Milk of itself is an exceedingly perishable product. Cheese preserves the most important nutrient parts of the milk in condition for consumption over a much longer period. The duration of this period and the ripening and other changes taking place depend very closely on the composition of the freshly made cheese. There is an intimate relation between the water, fat, protein and salt-content of the newly made cheese and the ripening processes which produce the particular flavors of the product when it is ready for the consumer. This relation is essentially biological. A cheese contain- BOOK OF CHEESE ing 60 to 75 per cent of water, as in " cottage cheese " (the sour-milk cheese so widely made in the homes), must be eaten or lost in a very few days. Spoilage is very rapid. In contrast to this, the Italian Parmesan, with 30 to 32 per cent of water, requires two to three years for proper ripening. The cheeses made from soured skim-milk probably represent the most ancient forms of cheese-making. Their origin is lost in antiquity. The makers of Roque- fort cheese cite passages from Pliny which they think refer to an early form of that product. It is certain that cheese in some form has been familiar to man throughout historic times. The technical literature of cheese-making is, however, essentially recent. The older literature may be cited to follow the historical changes in details of practice. 2. Cheese-making as an art has been developed to high stages of perfection in widely separate localities. The best known varieties of cheese bear the geographical names of the places of their origin. The practices of making and handling such cheeses have been developed in intimate relation to climate, local conditions and the habits of the people. So close has been this adjustment in some cases, that the removal of expert makers of such cheeses to new regions has resulted in total failure to transplant the industry. 3. Cheese-making as a science has been a compara- tively recent development. It has been partly a nat- ural outgrowth of the desire of emigrant peoples to carry with them the arts of their ancestral home, partly the desire to manufacture at home the good things met in foreign travel. Its development has been largely coincident with the development of the agricultural school GENERAL STATEMENT ON CHEESE 3 and the science of dairy biology. Even now we have but a limited knowledge of a few of the 500 or more varieties of cheese named in the literature. It is desirable to bring together the knowledge of underlying principles as far as they are known. No technical description of a cheese-handling process can replace experience. Descriptions of appearances and tex- tures of curd in terms definite enough to be understood by beginners have been found to be impossible. It is possible, however, to lay down principles and essentials of practice which are common to the industry and form the founda- tion for intelligent work. Cheese-making will be a science only as we depart from the mere repetition of a routine or rule-of-thumb practice and understand the underlying principles. 4. Problems in cheese-making. — Any understanding of these problems calls for a working knowledge of the very complex series of factors involved. These include the chemical composition of the milk, the nature of rennet and character of its action under the conditions met in cheese-making, the nature of the micro-organisms in milk, and the methods of controlling them, their relation to acidity and to the ripening of the cheese. To these scientific demands must be added acquaintance with the technique of the whole milk industry, from its production and handling on the farm through the multi- plicity of details of factory installation and organization, to those intangible factors concerned with the texture, body, odor and taste of the varied products made from it. Some of these factors can be adequately described ; others have thus far been handed on from worker to worker but have baffled every effort at standardization or definition. 4 THE BOOK OF CHEESE 5. History. — --The recorded history of the common varieties of cheese is only fragmentary. Practices at one time merely local in origin followed the lines of emigration. Records of processes of manufacture were not kept. The continuance of a particular practice depended on the skill and memory of the emigrant, who called his cheese after the place of origin. Other names of the same kind were applied by the makers for selling purposes. The widely known names were thus almost all originally geographical. Some of them, such as Gorgonzola, are used for cheeses not now made at the places whose names they bear. Naturally, this method of development has produced national groups of cheeses which have many common characteristics but differ in detail. The English cheeses form a typical group of this kind. Emigration to America carried English practices across the Atlantic. The story of cheese-making in America has been so closely linked with the development of the American Cheddar process that the historical aspects of the industry in this country are considered under that head in Chapter VIII. CHAPTER II THE MILK IN ITS RELATION TO CHEESE THE opaque whitish liquid, secreted by the mam- mary glands of female mammals for the nourishment of their young, is known as milk. The milk of the cow is the kind commonly used for cheese-making in America. 6. Factors affecting the quality. — The process of cheese-making begins with drawing the milk from the udder. The care and treatment the milk receives, while being drawn, and its subsequent handling, have a decided influence on its qualities. The process of cheese-making is varied according to the qualities of the milk. There are five factors that influence the quality of the milk for cheese-making : (1) its chemical composition ; (2) the flavor of feed eaten by the cow; (3) the absorption of flavors and odors from the atmosphere; (4) the health of the cow ; (5) the bacteria present. The first factor is dependent on the breed and individuality of the cow. The other four factors are almost entirely within the control of man. Of these factors-, number five is of the most importance, and is the one most frequently neg- lected. 7. Chemical composition. — The high, lt>w and average composition of milk is approximately as follows:* 6 THE BOOK OF CHEESE TABLE I COMPOSITION OF MILK WATER PER CENT FAT PER CENT CASEIN PER CENT SUGAR PER CENT ALBUMIN PER CENT ASH PER CENT High . . . Low .... 88.90 85.05 5.50 3.00 3.00 2.10 5.00 4.60 .72 .70 .73 .70 Average . . 87.47 3.80 2.50 4.80 .71 .72 8. Factors causing variation in composition. — The composition of cow's milk varies according to several factors. The composition of the milk of different breeds differs to such a degree that whole series of factories are found with lower or higher figures than these averages on account of dominant presence of particular kinds of cattle. The following table shows the usual effect of breed on fat and total solids of milk : TABLE II THE USUAL EFFECT OF BREED OF Cows ON FAT AND TOTAL SOLIDS OF MILK BREED OF Cows Fat Per Cent Total Solids Per Cent Jersey Guernsey 5.62 5 34 14.74 14 70 Shorthorn 4 17 13.41 Ayrshire 3.61 12.72 Holstein-Friesian 3 30 11.89 AVERAGES THE MILK IN ITS RELATION TO CHEESE 7 The figures1 in Tables I and II are compiled and aver- aged from a large number of analyses made at different agricultural experiment stations. This variation not only affects the fat, but all con- stituents of the milk. While there is a difference in the composition of the milk from cows of different breeds, there is almost as wide variation in the composition of the milk from single cows 2 of the same breed. With the same cow the stage of lactation causes a wide varia- tion in the composition of the milk.3 As the period of lactation advances, the milk increases in percentage of fat and other solids. 9. Milk constituents. — From the standpoint of the cheese-maker, the significant constituents of milk are . Exp. Sta. Kept. 1890, pages 237-241. Maine Exp. Sta. Kept. 1890, part II, pages 52-57. Conn. (Storrs) Exp. Sta. Kept. 1886, pages 119-130. Vt. Exp. Sta. Kept. 1890, pages 97-100. Vt. Exp. Sta. Kept. 1891, pages 61-74. N. Y. Exp. Sta. Kept. 1892, pages 299-392. N. Y. Exp. Sta. Kept. 1893, pages 39-162. Wis. Exp. Sta. Kept. 1890, pages 115-119. Conn. (Storrs) Exp. Sta. Kept. 1907, pages 152-156. N. Y. Exp. Sta. Kept. 1891, pages 139-142. N. Y. Exp. Sta. Kept. 1894, pages 31-86, 118-121. N. J. Exp. Sta. Kept. 1895, pages 136-137. Eckles, C. H., and R. H. Shaw. The influence of breed and individuality on the composition and properties of milk, Bur. An. Ind. Bui. 156, 1913. Eckles, C. H., and R. H. Shaw, Variations in the composition and properties of milk from the individual cow, U. S. Dept. Agr. Bur. An. Ind. Bui. 157, 1913. 2 Morrow, G. A., and A. G. Manns, Analyses of milk from different cows, 111. Exp: Sta. Bui. 9, 1890. 3 Eckles, C. H., and R. H. Shaw, The influence of the stage of lactation on the composition and properties of milk, U. S. Dept. Agr. Bur. An. Ind. Bui. 155, 1913. N. Y. Exp. Sta. Kept. 1892, pages 138-140. 8 THE BOOK OF CHEESE water, fat, casein, milk-sugar, albumin, ash and enzymes. These will be discussed separately. 10. Water. — The retention of the solids and the elim- ination of the water are among the chief considerations in cheese-making. Water forms 84 to 89 per cent of milk. Cheese-making calls for the reduction of this percentage to that typical of the particular variety of cheese desired with the least possible loss of milk solids. This final percentage varies from 30 to 70 per cent with the variety of cheese. The water has two uses in the cheese : (1) It imparts smoothness and mellowness to the body of the cheese ; (2) it furnishes suitable conditions for the action of the ripening agents. To some extent the water may supplement or even replace fat in its effect on the texture of the cheese. If the cheese is properly made, the water present is in such combination as to give no suggestion of a wet or " leaky " product. 11. Fat. — Fat is present in the milk in the form of suspended small transparent globules (as an emulsion). These globules vary in size with the breed and individ- uality of the cow and in color from a very light yellow to a deep yellow shade as sought in butter. Milk with small fat globules is preferred for cheese-making, because these are not so easily lost in the process. Milk-fat is made up of several different compounds called glycerids,1 which are formed by the union of an organic acid with glycerine as a base. Fat is important in cheese-making for two reasons : (1) Its influence on the yield of cheese; (2) its effect 1 N. Y. Exp. Sta. Kept. 1891, pages 143-162, 316-318. Wis. Exp. Sta. Kept. 1890, pages 238-247. Van Slyke, L. L., Conditions affecting the proportions of fat and protein in cow's milk, Jour. Am. Chem. Soc., 30 (1908), no. 7, pages 1166-1186. THE MILK IN ITS RELATION TO CHEESE 9 on the quality of the cheese. Many of the details of cheese-making processes have been developed to prevent the loss of fat in manufacture. The yield of cheese is almost directly in proportion to the amount of fat in the milk; nevertheless, because the solids not fat do not in- crease exactly in proportion to the fat, the cheese yield is not exactly in proportion to the fat. The fat, however, is a good index of the cheese-producing power of the milk. 12. Casein. — Cheese-making is possible because of the peculiar properties of casein. This is the fundamental substance of cheese-making because it has the capacity to coagulate or curdle under the action of acid and rennet enzymes. Casein is an extremely complex organic com- pound.1 Authorities disagree regarding its exact com- position, but it contains varying amounts of carbon, oxygen, nitrogen, hydrogen, phosphorus and sulfur, and it usually is combined with some form of lime or cal- cium phosphate. It belongs to the general class of nitrogen-containing compounds called proteins. It is present in milk in the form of extremely minute gelat- inous particles in suspension. Casein is insoluble in water and dilute acids. The acids, when added, cause a heavy, white, more or less flocculent precipitate. Rennet (Chapter III) causes the casein to coagulate (curdle), forming a jelly-like mass called curd, which is the basis of manufacture in most types of cheese. In 1 Van Slyke, L. L., and A. W. Bosworth, Composition and properties of some casein and paracasein compounds and their relations to cheese, N. Y. Exp. Sta. Tech. Bui. 26, 1912. Forbes, E. B., and M. H. Keith, A review of the litera- ture of phosphorus compounds in animal metabolism, Ohio Exp. Sta. Tech. Bui. 5, pages 32-36, 42-45. Van Slyke, L. L., and A. W. Bosworth, Condition of casein and salts in milk, N. Y. Exp. Sta. Tech. Bui. 39. 10 THE BOOK OF CHEESE the formation of this coagulum (curd) , the fat is imprisoned and held. The casein compounds in the curd hold the moisture and give firmness and solidity of body to the cheese. Casein contains the protein materials in which important ripening changes take place. These changes render the casein more soluble, and are thought to be the source of certain characteristic cheese flavors. 13. Milk-sugar. — Milk-sugar (lactose) is present in solution in the watery part of the milk. It forms on the average about 5 per cent of cow's milk. Since it is in solution, cheese retains the aliquot part of the totaj represented by the water-content of the cheese, plus any part of the sugar which has entered into combination with the milk solids during the souring process. The larger part of the lactose passes off with the whey. Lactose1 is attacked by the lactic-acid bacteria and by them is changed to lactic acid. Cheeses in which this souring process goes on quickly, soon contain a large enough percentage of acid to check the rotting of the cheese by decay organisms. Without this souring, most varieties of cheese will begin to spoil quickly. For each variety there is a proper balance between the souring, which interrupts the growth of many kinds of putrefactive bacteria, and the development of the forms which are essential to proper ripening. 14. Albumin. — This is a form of protein which is in solution in the milk. Albumin forms about 0.7 per cent of cow's milk. It is not coagulated by rennet. Most rennet cheeses, therefore, retain only that portion of the total albumin held in solution in the water retained, as in the case of milk-sugar. Albumin is coagulated by heat, forming a film or membrane upon the surface. There 1 Wis. Exp. Sta. Kept. 1901, pages 162-166. THE MILK IN ITS RELATION TO CHEESE 11 are certain kinds of cheese, such as Ricotte, made by the recovery of albumin by heating. 15. Ash. — The ash or mineral constituents make up about 0.7 per cent of cow's milk. This total includes very small amounts of a great many substances. The exact form of some of the substances is still unknown. Of these salts, the calcium or lime and phosphorus salts are most important in cheese-making. They are par- tially or completely precipitated by pasteurization. After such precipitation rennet fails to act * or acts very slowly ; hence pasteurized milk cannot be used for making rennet cheese unlesfe the lost salts are replaced, or the condition of the casein is changed by the addition of some substance, before curdling is attempted. 16. Enzymes. — Milk also contains enzymes. These are chemical ferments secreted by the udder. They have the power to produce changes in organic compounds with- out themselves undergoing any change. Minute amounts of several enzymes are found in milk as follows : Diastase, galactase, lipase, catalase, peroxidase and reductase. Just what part they play in cheese-making is not definitely known. 17. The flavor of feeds eaten by the cow. — Unde- sirable flavors in the milk are due many times to the use of feed with very pronounced flavors. The most common of these feeds are onions, garlic, turnips, cabbage, de- cayed ensilage, various weeds and the like. These un- desirable flavors reach the milk because the substances are volatile and are able to pass through the tissues of the animal. While feed containing these flavors is being digested, these volatile substances are not only present 1 Sammis, J. L., and A. T. Bruhn, The manufacture of cheese from pasteurized milk, Wis. Exp. Sta. Research Bui. 27, 1912. 12 THE BOOK OF CHEESE in the milk, but in all the tissues of the animal. By the time the process of digestion is completed, the volatile flavors have largely passed away. Therefore, if the times of milking and feeding are properly regulated, a dairy-man may feed considerable quantities of strong-flavored prod- ucts, such as turnip, cabbage and others, without any appreciable effect on the flavor of the milk. To ac- complish this successfully, the cows should be fed im- mediately before or immediately after milking, preferably after milking. This allows time for the digestive process to take place and for the volatile substances to disappear. If, however, milking is performed three or four hours after feeding, these volatile substances are present in the milk and flavor it.1 In the case of those plants which grow wild in the pasture, and to which the cows have continued access, it is more difficult to prevent bad flavor in the milk. The cows may be allowed to graze for a short time only, and that immediately after milking, without affecting the flavor of the milk. This will make it necessary to supplement the pasture with dry feed, or to have another pasture where these undesirable plants do not grow. Undesirable flavors are usually noticeable in the milk when the cows are turned out to pasture for the first time in the spring; and when they are pastured on rank fall feed, such as second growth clover. 18. Absorption of odors. — Milk, especially when warm, possesses a remarkable ability to absorb and retain odors from the surrounding atmosphere. 2 For 1 Baer, U. S., and W. L. Carlyle, Quality of cheese as affected by food, Wis. Exp. Sta. Bui. 115, 1904. 2 King, F. H., and E. H. Farrington, Milk odor as affected by silage, Wis. Exp. Sta. Bui. 59, 1897. THE MILK IN ITS RELATION TO CHEESE 13 this reason, the milk should be handled only in places free from such odor. Some of the common sources of these undesirable odors are bad-smelling stables, strong- smelling feeds in the stable, dirty cows, aerating milk near hog-pens, barn-yards and swill barrels. The only way to prevent these undesirable flavors and odors is not to expose the milk to them. The safest policy is to remove the source of the odor. 19. Effect of condition of the cow. — Any factor which affects the cow is reflected in the composition and physi- ological character of the milk. (1) Colostrum. Milk secreted just before or just after parturition is different in physical properties and chemical composition from that secreted at any other time during the lactation period. This milk is known as colostrum. It is considered unfit for human food, either as milk or in products manu- factured from the milk. Most states l consider colostrum adulterated milk, and prohibit the sale of the product for fifteen days preceding and for five days after par- turition. (2) Disease. When disease is detected in the cow, the milk should at once be discarded as human food. Some diseases are common both to the cow and to man, such as tuberculosis, foot-and-mouth disease. If such diseases are present in the cow, the milk may act as a carrier to man. Digestive disorders of any sort in the cow are frequently accompanied by undesirable flavors in the milk. These are not thought to be due to the feed, but to the abnormal condition of the cow. When the normal condition is restored, these undesirable flavors disappear. 1 N. Y. Agricultural Law, 1913, section 30. Mich. Agricultural Law, 1915, section 77. Wis. Agricultural Law, 1913, section 4601. 14 THE BOOK OF CHEESE 20. Bacteria in the milk. — Bacteria are microscopic unicellular plants, without chlorophyll. Besides bacteria, there are other forms of the lower orders of plants found in milk, such as yeasts and molds. While the bacteria are normally the more important, frequently yeasts and molds produce significant changes in milk and other dairy products. Bacteria are very widely distributed throughout nature. They are so small that they may easily float in the air or on particles of dust. Many groups of bacteria are so resistant to adverse conditions of growth that they may be present in a dormant or spore stage, and, therefore, not be easily recognized ; when suitable environments for growth are again produced, development begins at once. They are found in all surface water, in the earth and upon all organic matter. There are a great many different groups of bacteria; some are beneficial, and some are harmful. As they are so small, it is difficult to differentiate between the bene- ficial and harmful kinds, except by the results produced, or by a careful study in an especially equipped laboratory. The bacteria multiply very rapidly. This is brought about by fission ; that is, the cell-walls are drawn in at one place around the cell, and when the walls unite at the center, the cell is divided. There are then two bacteria. In some cases, division takes place in twenty to thirty minutes. Like other plants, they are very sensitive to food supply, to temperature and to moisture, as con- ditions of growth. Inasmuch as the bacteria are plant cells, they must absorb their food from materials in solution. They may live on solid substances, but the food elements must be rendered soluble before they can be used. Most bacteria prefer a neutral or slightly acid medium for growth, rather than an alkaline reaction. THE MILK IN ITS RELATION TO CHEESE 15 Ordinary milk makes a very favorable medium for the growth of bacteria, because it is an adequate and easily available food supply. In milk, certain groups of bacteria are commonly present, but many others which happen to get into it live and multiply rapidly. A favorable temperature is very necessary for such organisms to multiply. There is a range of temperature, more or less wide, at which each group of bacteria grows and multiplies with the greatest rapidity. This range varies with the different groups, but most of them find temperatures between 75° F. and 95° F. the most favorable for growth. Ex- cessive heat kills the bacteria. Low temperatures stop growth, but kill few if any bacteria. Temperatures of 50° F. and lower retard the growth of most forms of bacteria found commonly in milk. Many forms will slowly develop, however, below 50° and some growth will occur down to the freezing point. Milk held at 50° F. or lower will remain in good condition long enough to be handled without injury to quality until received in the cheese factory. In the place of seeds, some groups of bacteria form spores. The spores are exceedingly resistant to unfavorable conditions of growth, such as heat, cold, drying, food supply and even chemical agents. This property makes it difficult to destroy such bacteria. 21. Groups of bacteria in milk. — Milk when first drawn usually shows an amphoteric reaction; that is, it will give the acid and alkaline reactions with litmus paper. Under normal conditions, milk soon begins to undergo changes, due to the bacteria. Changes pro- duced in this way are called " fermentations " ; the agents causing them, "ferments." Normally the acid 16 THE BOOK OF CHEESE fermentation takes place first, and later other fermenta- tions or changes begin, which, after a time, so decom- pose the milk that it will not be suitable for cheese- making or human consumption. The following grouping of the organisms in milk is based on their effects on the milk itself l : I. Acid-producing types. II. Peptonizing types. III. Inert types. IV. Alkali-producing types. V. Butyric fermenting types. Each type of bacteria produces more or less specific changes in the milk. As a general rule, the predominance of one of these types is an aid in the interpretation of the quality of the product at the time of analysis, such as the age, the temperature at which it has been held, the conditions under which it was produced and, in some cases, the general source of the contamination. The reaction due to certain bacteria is utilized in the manu- facture and handling of dairy products; other groups have deleterious effects. (See Fig. 2.) 1 Conn. (Storrs) Exp. Sta. Kept. 1899, pages 13-68. Conn. (Storrs) Exp. Sta. Kept. 1903, pages 33-98. Conn. (Storrs) Exp. Sta. Kept. 1904, pages 27-88. Esten, W. M., and C. J. Mason, Sources of bacteria in milk, Conn. (Storrs) Exp. Sta. Bui. 51, 1908. Rogers, L. A., and B. J. Davis, Methods of classifying the lactic acid bacteria, U. S. Dept. Agr. Bur. An. Ind. Bui. 154, 1912. Bergey, D. H., The colon-aerogenes group of bacteria, Jour. Med. Research, Boston, Vol. XIX, pages 175-200, 1908. Conn, H. W., Classification of dairy bacteria, Conn. (Storrs) Exp. Sta. Rept. 1906. Rogers, L. A., Bacteria in milk, U. S, Dept. Agr., Farmers' Bui. 490, 1912. THE MILK IN ITS RELATION TO CHEESE 17 22. Acid fermentation of milk. — By far the most common and important fermentation taking place in milk is due to the action of the lactic acid-forming bacteria on the milk-sugar or lactose. The bacteria that bring about this fermentation may be divided into several groups on the basis of their morphology, proteolytic activity, gas production, temperature adaptation and FIG. 2. — Effect of different fermentations of milk: U, Curd pitted with gas holes ; G and 0, gassy curds which float ; K, smooth, solid desirable curd. production of substances other than lactic acid. The larger number of organisms producing lactic acid in milk also produce other organic acids in greater or less abundance. Inasmuch as lactic acid is the principal sub- stance produced, they are called lactic acid organisms. This group contains different kinds of organisms which may be subdivided into small groups as follows : (a) Bacterium lactis-acidi group. (b) Bacterium colon-aerogenes group. 18 THE BOOK OF CHEESE (c) Acid peptonizing group. (d) Bacillus bulgaricus group. (e) Acid cocci or weak acid-producing group. 23. Bacterium lactis-acidi group. — There are many strains or varieties in this group which are closely related in their activities. They are universally present in milk and are commonly the greatest causal agent in its souring. They are widely distributed in nature. At a temperature of 65° F. to 95° F., these bacteria grow and multiply very rapidly; at 70° F. (approximately 20° C.) these forms usually outgrow all others. The total amount of acid produced in milk by these organisms varies from 0.6 of one per cent to 1 per cent acid calculated as pure lactic acid. These forms coagulate milk to a smooth curd of uniform consistency. In addition to the lactic acid, there are produced traces of acetic, succinic, formic and proprionic acids, traces of certain alcohols, alde- hydes and esters. Substances other than lactic acid are not produced by organisms of this group to such an extent as to impart undesirable flavors to the milk. The action of this group on the milk proteins is very slight. They produce no visible sign of peptoniza- tion. The B. lactis-acidi group of organisms are essential to the production of the initial acidity necessary in most types of cheese. The practical culture and utilization of them for this purpose under factory conditions are discussed in Chapter IV, entitled " Lactic Starters." 24. Colon-aerogenes group. — This group takes its name from a typical species, Bacterium coli communis, which is a normal inhabitant of the intestines of man and animals, and from Bacterium coli aerogenes, which is similar in many respects to B. coli communis. The THE MILK IN ITS RELATION TO CHEESE 19 initial presence of these bacteria in milk is indicative of fecal contamination or unclean conditions of production. These organisms, however, grow and develop in milk very rapidly at high temperatures of handling. The total acidity produced by these forms is less than that by the Bacterium lactis-acidi group. Of the acid produced, less than 30 per cent is lactic acid; the other acids are formic, acetic, proprionic and succinic. The large per- centage of these acids, with comparatively large amounts of certain alcohols, aldehydes and esters, invariably im- part undesirable flavors and odors to the milk. Mem- bers of this group uniformly ferment the lactose with the production of the gases, carbon dioxide and hydrogen. The milk is coagulated into a lumpy curd, containing gas pockets. 25. Acid peptonizing group. — These are often as- sociated with colon organisms. The group includes those bacteria which coagulate milk with an acid curd and subsequently partly digest it. They grow and mul- tiply rapidly at a temperature between 65° and 98° F. They impart undesirable flavors and odors to the milk, which appear to be due to the formation of acids other than lactic acid, and to action on the milk proteins. 26. Bacillus bulgaricus group. — These organisms grow best at a temperature of 105° to 115° F. They will de- velop at lower temperatures, but not so rapidly. They survive heating to 135° F. without loss of vigor, as occurs in Swiss cheese-making. They produce from 1 to 4 per cent of acid in milk, which is practically all lactic acid. They do not produce gas. They impart no undesirable flavors to the milk. 27. Acid cocci or weak acid-producers. — This group of organisms is not very well defined. It consists mostly 20 THE BOOK OF CHEESE of coccus forms, commonly found in the air and in the udder. Their presence in the milk may indicate direct udder contamination. These are regarded as of little importance, unless in very large number, and they have been only partially studied. They produce little or no lactic acid, and small amounts of acetic, proprionic, butyric and caproic acids. These forms rarely create enough acid to coagulate milk. 28. Peptonizing organisms. — This group includes all bacteria which have a peptonizing effect on the milk. It includes the acid peptonizing organisms, although they are of primary importance in the acid type of bac- teria, because the acid-producing power is greater than the peptonizing power. Some of the specific organisms in this class are Bacillus subtilis, Bacterium prodigiosus and Bacterium liquefaciens. These are commonly found in soil water and in fecal material. The presence of these organisms denotes contamination from such sources. such as Mann's, Publow's, Far- rington's and Marschall Js. 82. Rennet tests. — Several rennet tests have been devised, but the one most widely used is the Marschall (Fig. 10). This consists of a 1 c.c. pipette to measure the rennet extract, a small bottle in which to dilute the extract, a special cup to hold the milk and a spatula to mix the milk with the rennet extract. This cup has on the inside from top to bottom a scale graduated from 0 at the top to 10 at the bot- tom. There is a hole in the bottom to allow the milk to run out. 83. Marschall rennet test. — To make a Marschall rennet test, 1 c.c. of rennet extract is measured, with the 1 c.c. pipette, and placed in the bottle. Care should be exercised to rinse out the pipette. The bottle is then filled to the mark with cold water. After the milk has been heated to the setting temperature, 84°- 86° F., the cup is filled with milk and set on the edge of the vat so that the milk running out through the hole in the bottom of the cup will flow into the vat. Just as the surface of the milk reaches the 0 mark on the cup, the diluted rennet extract is added and thoroughly mixed i , FIG. 10. — Marsc all rennet test. CURD-MAKING 63 with the milk, using the small spatula to stir it. The rennet and milk should be mixed until it has run down at least one-half space on the scale in the cup. As the rennet begins to coagulate the milk, it runs slower from the hole in the bottom of the cup, until it finally stops. When it stops, the point on the scale indicated by the surface of the coagulated milk is noted. The test is recorded by the number of spaces the surface of the milk lowers from the time the rennet is added until it is coagulated. This test depends on three factors : the strength of the rennet extract, the temperature of the milk, the acidity of the milk. The more acid, the quicker the milk will coagulate. To measure any one of these factors, the other two must be constant. The variable factor is the acidity of the milk. This test will not indicate the percentage of acid in the milk, but is simply a comparative test to be used from day to day; for example, if the rennet test to-day shows three spaces, and the operator makes that milk into cheese and the process seems to be normal, it shows that for good results in this factory, milk should be ripened to show three spaces every day. If the next day the milk showed four spaces, it should be allowed to ripen more until it shows three spaces. If it shows only two spaces, this indicates that the milk has too much acid development or is over- ripe. A cheese-maker will have to determine at what point to set his milk, because the test will vary from one factory to another. 84. Comparison of acid and rennet test. — Each of these tests has its advantages and disadvantages. The advantage of the acid test is that it can be made as well of warm as cold milk. This is of great impor- tance in determining whether the milk delivered by any 64 THE BOOK OF CHEESE patron is too ripe to be received. The acidity of other materials, such as whey and starter, can be determined as well as that of milk. The disadvantages are that it is difficult to get the alkali solution of the proper strength and the solution is liable to deteriorate on standing. It requires a careful exact operator to make the test. The advantages of the rennet test are that it is easy to make, and it requires no materials that are hard to re- place. The disadvantage is that the milk must be warmed to the same temperature before a comparative test can be made. The size of the outlet in cups varies. It does not indicate the percentage of acid present in the milk. It is simply a comparative test. To obtain the best result, both tests should be used in conjunction. 85. Control of acid. — The control of acidity in curd and cheese is dependent on the control of the moisture or water-content. The control of both factors is very impor- tant in relation to the quality 1 of the cheese. Often acio> ity is spoken of when moisture is really intended, and vice versa. The close relation between the moisture and acidity is due to the presence of the milk-sugar in solution in the milk-serum which becomes the whey of cheese- making. Water or moisture in cheese consists of the remnant of this whey which is not expelled in the making process. During manufacture and the ripening process, the milk-sugar is changed to lactic acid. A cheese may be sweet when first made and after a time become sour because it contains too much moisture in the form of whey. Excess of whey carries excess of milk-sugar from which fermentation produces intense acidity. 1 Doane, C. F., The influence of lactic acid on the quality of cheese of the Cheddar type, U. S. Dept. Agr. Bur. An. Ind. Bui. 123, pages 1-20, 1910. CURD-MAKING 65 Various tests have been devised to determine the amount of acid developed at the different stages of manu- facture. These tests are described on page 61. By the use of such tests, the development of acid during the manufacturing process can be very accurately determined. There is no quick, accurate test to determine the amount of moisture in the curd. The cheese-maker has to rely on his own judgment, guided largely by the appearance, feeling and condition of the curd. After the rennet extract has been added, all control of the acid development is lost. The cheese-maker can determine rather accurately how fast the acid will de- velop during the ripening of the milk. This shows the importance of the proper ripening. The amount of acid developed during the different stages of the manufactur- ing process can be approximately followed with the various acid tests. The manufacturing process should then be varied to obtain the proper relation between the moisture and the acid present. The only time that the acidity may be controlled is when the milk is being ripened. If too much acid is developed before the rennet is added, there is apt to be too much acid at each stage of the manu- facturing process. This is liable to hurry the cheese- making process and to cause a loss, both in quality and quantity of cheese, and may cause a high acid or sour cheese. If sufficient acid is not developed at the time the rennet is added or if the milk is not sufficiently ripened, the acid is liable not to develop fast enough so that there will not be sufficient at each step in the cheese-making process. Such a cheese is called " sweet." There are several conditions which will cause an over-development of acid. Such a cheese is called " acidy " or " sour." These factors are within the control of the cheese-maker, 66 THE BOOK OF CHEESE hence should be avoided. A sour cheese shows lack of skill and care on the part of the cheese-maker. Conditions canning an acidy or sour cheese: Receiving sour or high acid milk at the cheese -factory. Use of too much starter. Ripening the milk too much before the rennet is added. Removing the whey before the curd is properly firmed, hence leaving it with too much moisture. Development of too much acid in the whey before the whey is removed. Improper relationship between the moisture and acidity at the time of removing the whey. Conditions causing deficient acid: Adding the rennet before sufficient acid has developed. Not using sufficient starter. Not developing sufficient acid in the whey. 86. Acidity and rennet action. — The rennet extract acts only in an acid medium. The greater the acid de- velopment, within certain limits, the faster the action of the rennet. If enough acid has developed to cause a coagulation of the casein, the rennet will not coagulate the milk. This is one reason why Cheddar cheese cannot be made from sour milk. 87. Acidity and expulsion of the whey. — The con- traction of the curd and expulsion of the whey are so closely related that they may be treated under the same heading. The more acid, the faster the whey separates from the curd, other conditions being uniform. The relation of acidity and firmness of the curd to temper- ature of the curd is another important factor in the suc- cessful manufacture of cheese. The higher the acidity, the faster the temperature of the curd can be raised with- CURD-MAKING 67 out any harmful effects. If the temperature is raised too fast in relation to the acidity, the film surrounding each piece of curd will become toughened so that the moisture will not be able to escape. When this condition exists, the curd will feel firm but when the pieces are broken open the inside is found to be very soft. This results in a large loss later or may cause a sour cheese. It usually causes an uneven texture and color in the cheese. 88. Acidity in relation to cheese flavor. — Just what part the acid plays in the development of cheese flavor is not known. If a certain amount of acid is not present, the characteristic cheese flavor does not develop. If too much acid is developed, it gives the cheese a sour flavor which is unpleasant. If sufficient acid is not developed, the other undesirable factors seem to be more active, causing very disagreeable flavor and may cause the cheese to putrefy. A cheese with a low acid usually develops a very mild flavor, and if carried to extremes, as in the case of some washed curd cheese, the true cheese flavor never develops. 89. Acidity in relation to body and texture of cheese. — If a cheese is to have a close, smooth, mellow, silky body and texture, a certain amount of acid develop- ment is necessary. If too much acid is developed, the body and texture will be dry, harsh, sandy, mealy, corky. If the acid is not sufficient the cheese may be soft or weak bodied, and is usually characterized by " Swiss curd holes," which are spaces of various sizes usually more or less round and very shiny on the inside. 90. Acidity in relation to cheese color. — An over- development of acidity affects the color of a cheese. If this development of acidity is uniform throughout the cheese, it causes the color to become pale or bleached. 68 THE BOOK OF CHEESE If this development is uneven, due to the uneven distri- bution of moisture, the color will be bleached in spots, causing a mottled effect. 91. Control of moisture.1 — The cheese-maker must use skill and judgment in regulating the amount of mois- ture in relation to the firmness of the curd and the acid. Since there are no quick accurate tests to determine the amount of moisture, this is left entirely to the judg- ment of the operator. Certain methods of handling the curd reduce the moisture-content, while others in- crease it. The cheese-maker must decide how to handle the curd. If the curd becomes too dry, methods should be employed to increase the moisture, and vice versa. Causes of excessive moisture: Cutting the curd coarse. Cutting the curd after it has become too hard. Setting the milk at a high temperature. Use of excessive amount of rennet extract. Low acid in the curd at the time of removing the whey. Not stirring the curd with the hands as the last of the whey is removed. High piling of the curd during the cheddaring process. Piling the curd too quickly after removing the whey. Use of a small amount of salt. Holding the curd at too low a temperature after the whey is removed. Soaking the curd in water previous to salting. Allowing the curd to remain in the whey too long so that it reabsorbs the whey. Heating the curd too rapidly. 1 Fisk, W. W., A study of some factors influencing the yield and moisture content of Cheddar cheese, Cornell Exp. Sta. Bui. 334, 1913. CURD-MAKING 69 Causes of insufficient moisture: Cutting the curd too fine or breaking up the pieces with the rake into too small pieces. Cutting the curd too soft. Stirring the curd too much by hand as the last of the whey is being removed. Developing high acid in the curd at the time of removing the whey. Insufficient piling of the curd during the cheddaring process. Using a large amount of salt. High temperature and low humidity in the curing room. 92. Relation of moisture to manufacture and quality. — (1) Flavor: If the cheese contains too much moisture, it is likely to develop a sour or acidy flavor. A cheese with a normally high moisture-content usually ripens or develops a cheese flavor much faster than one with a lower moisture^ontent, other conditions being uniform. A cheese with a high moisture-content is much more liable, during the curing process, to develop undesirable flavors than is one with a lower moisture-content. (2) Body and texture: A cheese containing too much mois- ture is very soft and is difficult to hold in shape. Such a product breaks down very rapidly and is usually pasty and sticky in texture. If too .little moisture is present, the cheese is very dry and hard, and cures or ripens very slowly because of the lack of moisture together with milk- sugar from which acid may be formed. Dry cheeses are usually harsh, tough and rubbery in texture. Such cheeses also have poor rinds. (3) Color: If the ideal conditions exist, the moisture will be evenly distributed throughout the cheese. The spots containing more 70 THE BOOK OF CHEESE moisture will be lighter in color. If a cheese con- tains so much moisture that it becomes " acidy," the effect is the same as when too much acid is developed, that is, the color becomes pale from the action of the acid. (4) Finish: A cheese containing too much moisture is usually soft. A good rind does not form. Such a cheese loses its shape very easily, especially in a warm curing room. (5) Quality: A cheese with a high mois- ture-content is usually marketable for only a very short period. Such a product usually develops flavor very quickly in comparison to a dry cheese. It must be sold very soon because if held too long, the flavor be- comes so strong as to be undesirable, and objectionable flavors are liable to develop. In some cases, such cheeses rot. 93. Relation of moisture to acidity. — From the pre- ceding discussion, it is evident that the relation between the moisture and acidity is very close, in fact so intimate that in some cases it is difficult to distinguish one from the other when the quality of the cheese is considered. The proper relation of the moisture and the acidity de- termines the quality of the resulting cheese. If too much acid is developed during the manufacturing process, the product will be sour. If too much moisture is retained in the form of whey, the cheese will be sour. The less acid in the curd, the more moisture in the form of whey may be retained in the curd without causing a sour cheese. The proper relationship between the mois- ture and the acidity must be maintained or a sour cheese will result. The relation of the moisture to the acidity also has an influence on the curing. If the cheese has a low develop- ment of acidity and a low moisture-content, it will cure CURD-MAKING 71 very slowly. The increasing of either the acidity or moisture usually increases the rate of cheese ripening, other factors being the same. The relation of the acidity and the moisture is so im- portant that it cannot be neglected without injuring both the quality and quantity of cheese. This knowl- edge can be obtained only by experience. 94. Setting temperature. — The temperature of ren- neting makes very much difference in the texture of the product. The enzyme rennin is sensitive to very slight changes in temperature. Below 70° F., its rate of action is very slow. Beginning with approximately 20 per cent of its maximum effectiveness at 70° F. (the curdling point for Neufchatel), it has risen to 65 per cent at 84° F., to 70 per cent at 86° F., as used in Cheddar, to about 80 to 85 per cent at 90-94° F., as used in Lim- burger. At 105° F. it reaches its maximum effective working rate to fall from that efficiency to about 50 per cent at 120° F. Curdling at low temperature lengthens the time required for the same amount of ren- net to curdle a given quantity of the same milk. The texture of curd produced at temperatures between 70° F. and 84° F. is soft, jelly-like, friable rather than rubbery. At 86° F. it begins to show toughening or rubbery char- acters which become very marked at 90° F. to 94° F. as used in Limburger. With the increased Vigor of action as it passes its maximum rate of action at 105° F., the texture tends to become loose, floccose to granular. Aside from the Neufchatel group, the work- ing range of temperatures for the renneting period runs from about 84° F. to about 94° F., a range of barely 10° F., or the use of 65 per cent to 80 or pos- sibly 85 per cent of the maximum efficiency of the 72 THE BOOK OF CHEESE rennet. Within this range of temperature, the curd has the physical characters demanded for making most vari- eties of cheese. 95. Strength of coagulating materials. — Rennet and pepsin preparations vary in strength and in keeping quality. With a particular stock, changes go on to such a degree that the last samples from a barrel of rennet are much weaker than the earlier ones. Each sample, barrel, keg or bottle should be tested before used. In continuous work the results of each day's work furnish the guide for the next day's use of a particular lot of rennet. 96. Amount of coagulating materials to use. — For most varieties of cheese, sufficient rennet extract or pepsin is added to the milk to give a firm curd in twenty- five to forty minutes. Of the ordinary commercial rennet extract, this requires from two and one-half to four ounces to one thousand pounds of milk. This gives a maximum of one part rennet for each four to six thousand parts of milk. The great strength of the rennet extract is thus clearly shown. 97. Method of adding rennet. — Before rennet is added to the milk, it is diluted in about forty times its volume of cold water, which chills the enzyme and retards its action until it can be thoroughly mixed with the milk. If the material is added without such dilution, the concentrated extract produces instant coagulation in the drops with which it comes in contact, forming solid masses from which the enzyme escapes only slowly to diffuse throughout the mass. Uniform coagulation thus becomes impossible. After the rennet extract has been diluted with cold water, it should be distributed the entire length of the vat in an even stream from a pail. It should then be mixed with the milk by stirring from CURD-MAKING 73 top to bottom for about three to four minutes. For this purpose, either a long-handled dipper or a wooden rake may be used. A dipperful should be drawn from the gate and stirred into the vat, otherwise the milk in the gate will fail to coagulate properly because the rennet diffuses too slowly to reach and affect all the milk at that point. The milk should be stirred on the top, preferably with the bottom of a dipper, until signs of coagulation begin to appear. This stirring keeps the cream from rising. There are various ways or signs to indicate when the coagulation has gone to the stage at which the mix is about to become thick : (1) The milk becomes lazy or thicker as the finger is passed through it; (2) bubbles caused by moving the finger remain on the milk longer, usually until one can count ten when ready to thicken. If the milk is stirred too long or after it begins to thicken, the result is a granular sort of curd, and there will be an abnormally large loss of fat in the manufacturing process. The addition of the rennet and subsequent stirring re- quire the exercise of great care and constant attention to details. The cheese-maker can do nothing else for those few minutes. When through stirring, it is a good plan in cold weather to cover the vat with a cloth as this will keep the surface of the curd warm. In summer the same cover will keep out the flies. Causes of a delayed coagulation : (1) Weak rennet extract or too small an amount. (2) Low temperatures due to inaccurate thermometers. (3) Pasteurized milk. (4) Presence of abnormal bacterial ferments. (5) Presence of preservatives. 74; THE BOOK OF CHEESE (6) Heavily watered milk. (7) Use of badly rusted 1 cans. (8) Milk containing small amounts of casein or cal- cium salts. Causes of uneven coagulation: (1) Uneven temperature of the mix in the vat, due to lack of agitation. (2) Uneven distribution of the rennet extract. (3) Adding rennet to vat too soon after heating, while the sides and bottom are still hot, causes curd to stick to sides and bottom of the vat making cutting difficult. (4) Sloshing after the milk begins to thicken breaks the curd and causes it to whey off. 98. The curdling period. — The time allowed for rennet action also affects the texture of the 'curd. The enzymes of rennet (rennin and pepsin) do not cease acting with the thickening of the milk. In many cheeses, the handling process begins as soon as the curd has become solid enough to split cleanly before a finger thrust into it. If let stand further, the same curd mass will con- tinue to harden with the progressive separation of whey ; this shows first as drops (" sweating ") on its surface, which then increase in number and size until they run together and form a sheet of whey. The limit of such action is difficult to measure. The solidifying process ceases in a period of hours. The further action of the enzymes is digestive in character and goes on slowly. It requires a period of weeks or even months to accomplish measurable results at the working temperatures in use in the trade. Other ripening agents with more rapid 1 Olson, G. A., Rusty cans and their effect upon milk for cheese-making, Wis. Exp. Sta. Bui. 162, pages 1-12, 1908. CURD-MAKING 75 action intervene to shape the final result. It follows that the rennet factor in the ripening changes found at the end of the period is almost negligible for most varieties of cheese, although it appears to be measurable in some varieties. 99. Cutting or breaking l the curd. — As soon as curd is formed, separation of whey begins upon the surface and perhaps around the sides of the vessel. This is accompanied by shrinkage and hardening of the mass. If the curd remains unbroken, the separation is extremely slow. In cheese-making practice, such curd masses may be dipped at once into hoops as in Camembert, dumped in mass into cloths for drainage as in Neufchatel or, as in the larger number of cheeses, cut or broken in some characteristic manner. After the curd mass is firm, the rate at which subsequent changes take place depends largely on the size of the particles into which the curd is cut. The smaller the particles, the quicker the water is expelled. Consequently the development of the acidity and other changes take place more slowly. For this reason the curd should be cut into pieces of uniform size. If the work is not properly performed, the pieces of curd of various sizes will be at different stages of development. The fine particles will be firm and elastic while the larger particles are still soft and full of whey and may be de- veloping too much acid. The knives should be inserted into the curd obliquely so that they will cut their way 1 The term " broken " is included here because the use of some curd-breaking tool has always formed a step in certain com- mercially successful processes. In every case in which careful experimental work has been done the curd knife has been suc- cessfully substituted for the breaking tool and has reduced the losses of fat and casein and in addition aided in obtaining more uniform cheese. 76 THE BOOK OF CHEESE into the curd and not break it. The horizontal knife is used lengthwise of the vat and cuts the curd into layers of uniform thickness. The perpendicular knife then is used lengthwise and crosswise of the vat. It first cuts the curd into, strips and then into cubes. The knives may have wire blades or steel blades, some operators preferring one and some the other. Whichever is used, the blades should be close enough together to give the fineness of curd desired. After the knife passes through, the cut faces quickly become covered with a smooth coating, continuous over all exposed areas. This surface has the ap- pearance of a smooth elastic coating or film. This can be seen by carefully breaking a piece in the hand. It is this film which holds the fat within the pieces of curd. If the film is broken, some of the fat globules are lost because the rennet extract acts only on the casein and that in turn holds the fat. All the fat globules which come in contact with the knives as they pass through the curd will be left between the pieces of curd and will pass off in the whey. If care is exercised in cutting, the loss of fat will be confined to what may be called a mechanical loss. This is similar to the loss of the sawdust when sawing a board. This loss in American Cheddar is about 0.3 per cent and cannot be avoided. If it is greater than this, it is due to negligence on the part of the cheese-maker or the poor condition of the milk. The cutting of the curd into small pieces may be considered a necessary evil. If the moisture could be expelled from the whole mass without disturbing it, this fat loss could be prevented. The cutting, breaking or turning should be done with the greatest care, that the loss may be as small as possible. CURD-MAKING 77 100. Curd knives. — For cutting curd, special knives have been devised (Fig. 11). They consist of series of parallel blades fixed in a frame to make cuts equidistant. The blades run vertically in one, horizontally in another. Horizontal Perpendicular Horizontal Perpendicular FIG. 11. — Blade and wire curd knives. They are spaced according to the demands of the variety of cheese to be made. Wires stretched in a frame take the place of blades in some makes of curd knife. 101. Heating or " cooking." — Curdling by rennet has already been shown to be markedly hastened by moderate heating. After the coagulum or curd is formed, the making process may be completed without the application of further heat, as in Neufchatel, Camembert and related forms (Fig. 12) and in some practices with Limburger. In other forms and especially in the hard cheeses in which cutting of curd is a prominent 78 THE BOOK OF CHEESE part of the process, the curd after being cut is reheated or " cooked." The cooking process hastens the removal of the whey, thus shortening the time required to reduce 12545 FIG. 12. — The heat relation. See pages 77 and 87. the water-content of the mass to the percentage most favorable for the type of cheese desired. The process also produces marked changes in the physical character CURD-MAKING 79 of the curd mass. With the rise in temperature the casein becomes elastic first, then approaches a melting condition and assumes a tough, almost rubbery consistency. The final texture is the result of the combination of the amount of rennet added, the temperature, the acidity reached during the process, and the final water-content of the mass. 102. Draining (including grinding, putting into hoops or forms and pressing) . — The reduction of the water in the curd begins almost as soon as the curd becomes firm. It is aided by cutting or breaking, by the retention of the heat applied before renneting and by the second- ary heating or cooking used in making certain groups of cheeses. In many varieties special apparatus is provided in the form of draining boards, draining racks or bags to hasten the removal of the whey as fast as it separates. The draining process continues until the cheese has reached its final form and weight. The intervening process of matting in the Cheddar group involves a com- bination of a souring process with the removal of whey, during which the cubes of curd become fused into semi- solid masses. If such masses are formed, they must be ground up before the cheese can be given its final form in the hoop. The draining process, therefore, may take any one of many forms varying from the direct transfer of freshly formed curd into hoops in which the entire draining process is completed, to an elaborate series of operations which end in pressing curd drained to approxi- mately its final condition before it is placed in the hoop. 103. Application to cheese. — From the discussion of these factors, it is evident that the cheeses produced will differ widely with the differences in manipulation. If one considers essential constituent substances separately, 80 THE BOOK OF CHEESE the water-content of the finished product is found to vary from 30 per cent in Parmesan to 75 per cent in cottage cheese. The fat-content runs from a trace in some varieties to 60 per cent in some cream cheeses. The texture of the casein, which gives character to the product, varies from the tough or glue-like consistency of freshly made Swiss to the buttery condition of a cream or Neufchatel cheese. Inside such limits the tastes of different peoples have led to the manufacture of many kinds of cheese. Each of these varieties represents some particular combination of curd-making factors and ripening conditions which produces a cheese suited to the taste of the maker and consumer of that country or community. CHAPTER VI CLASSIFICATION THE literature of cheese-making contains reference to more than 500 names for varieties of cheese. Many of these can be thrown readily into great groups or fam- ilies in which there are variations in unessential detail without modifying the characteristic texture and flavor of the product. Many varietal names are attached to the product of single factories or factory groups. Such varieties frequently differ only slightly in size or shape, or in stage of drainage or of ripening, from widely known varieties or other similar local forms. The descriptions recorded for such varieties commonly emphasize minor differences in manipulation without showing differences in essential factors. Vessels of particular size are pre- scribed to be made of wood, earthenware, or of a special metal. These details specify the exact size and shape of hoops, the use of particular styles of cutting or breaking instruments and of certain stirring tools, the material and construction of mats and draining racks. The descriptions themselves are very commonly in- adequate. The variable factors in cheese-making are fat-content of the milk, acidity, temperature of setting, amount of rennet, time allowed for curdling and the method of draining the curd. The differences in practice lie, with few exceptions, in the amount or intensity of particular factors, not differences in kind or quality of G 81 82 THE BOOK OF CHEESE treatment. Such contrasts are quantitative, not qualita- tive. A great number of combinations is possible by small variations of these factors. Varieties selected as types of groups give marked con- trasts in character, but comparison of large numbers of forms shows that almost every gradation from group to group can actually be found. Within groups frequently the same physical results in texture and flavor can be obtained by combinations or adjustments of factors for the purpose of offsetting or counteracting the effects of one change in practice by the manipulation of other factors. In ripening, an equally large range of practices makes possible the development of very different qual- ities in mature cheeses from the same lot. Only a few of the large number of described varieties have obtained even national importance; fewer still are known outside the country of origin. In spite of the success of special products when properly advertised, the largest place in the market is clearly accorded to the standard forms which are widely known. 104. Basis of classification. — A series of these widely known forms has been chosen as typical of groups in a system of classification adapted from the French of Pouriau. No completely satisfactory scheme of classifying all of these varieties has been devised. The grouping proposed here is based on the principles of curd-making already discussed together with consideration of the ripening processes to be discussed with each group. 'The factors that actually influence the quality of the final product are separated as completely as possible from non-essential operative details. The common use of the terms " soft " and " hard " cheese is based on the single arbitrary fact of texture. The term " semi-hard " cheese may be conveniently CLASSIFICATION 83 applied to a miscellaneous group of unrelated families which are intermediate in texture between such soft forms as Neufchatel or Camembert and really hard cheeses like Cheddar or Parmesan. Although these terms are not made the main basis of the proposed grouping, their application to sections is indicated. Classification based on the essential facts of manufac- ture is, however, really helpful. ANALYTICAL TABULATION OP GROUPS Section I. Cheeses with sour milk flavor only (Eaten fresh). (Soft cheeses 45 to 75 % water) PAGE 1. Curdled by souring, Cottage cheese and its allies in America, many related varieties in Europe 90 2. Curdled by souring and rennet — the Neufchatel group 95 a. Skim — Skim-milk Neufchatel . . . 105 6. Part skim to whole milk — American or Domestic Neufchatel 106 c. With fat added — the cream cheeses of the Neufchatel group (both American and European) — such as Cream, Ger- vais, Malakoffs, etc 108 Section II. Cheeses ripened. Subsection A. Soft cheeses (40 to 50% water). 1. Curdled by souring, heated, then ripened. Hand cheese, Pennsylvania pot cheese, Harz, etc 112 2. Curdling by souring and rennet, ripened Ripened (French) Neufchatel . .114 3. Curdled primarily by rennet. a. Ripened by mold — Camembert, Brie and their allies . . .117 6. Ripened by bacteria. * Made from soft or friable curd — d'Isigny, Liederkranz, etc. 134 ** Made from firm or tough curds — Limburger and allies . . 139 84 THE BOOK OF CHEESE Subsection B. Semi-hard cheeses, firm, well-drained (38 to 45% water). , PAQB a. Curd not cooked, ripened by molds. * Made from friable curd — Roquefort 150 ** Made from firm or tough curd — Gorgonzola, Stilton and such French forms as Gex, Septmoncel 158 6. Curd cooked and ripened by bac- teria, — brick, Munster, Port du Salut (Oka) . . . . . 164 Subsection C. Hard cheeses, cooked and pressed (30 to 40% water). a. Ripened without gas holes. 1. Dutch — Edam, Gouda ... 173 2. Danish. 3. The Cheddar group. * English — Cheddar and numer- ous related forms known principally in Great Britain 184 ** American — the factory Ched- dar of United States and Canada ....... 184 6. Ripened with the development of gas holes. * Holes large — Swiss-Emmen- thal, Gruy^re, American Swiss 276 ** Holes small — Parmesan and related varieties .... 288 Such a classification brings together series of products in which there is essential similarity in the final output, however great the differences in manipulation. It does not consider all varieties and specialties. Some of these groups are important enough to demand special mention. 105. Processed cheeses. — Cheese of any group may be run through mixing and molding machines and re- packaged in very different form from that characteristic of the variety. In such treatment, the texture and CLASSIFICATION 85 appearance may be so changed as to give the effect of a new product. Substances (such as pimiento) are added to change the flavor. Or the product may be canned and sterilized with equally great change of flavor and tex- ture. One thus finds Club made from Cheddar; Pimi- ento from Cream, Neufchatel or Cheddar; similarly olive, nut and other combinations are made. The possible variations are numerous. 106. Whey cheeses. — Several products bearing cheese names are made from whey. These take the forms of the recovery of the albumin and casein separately or in a single product, and the recovery of the milk-sugar either alone or with the albumin. Whey cheeses have been especially developed by the Scandinavian people, although some of them have their origin in the south of Europe. Certain of these varieties are produced on a limited scale in America. There are a number of forms fairly widely known that are difficult to place in this scheme of groups. Among these are Caciocavallo, Sap Sago. 107. Soft and hard cheeses. — Another . commonly used classification makes two groups: (1) soft cheeses; (2) hard cheeses. In such a classification the semi-hard ^roup presented here is included with the soft cheeses. Some cheeses of this group are soft in texture. This is correlated with high water-content, high fat-content or both together. 108. Relation of moisture to classes. — In this classi- fication the water-content reflected in the texture of the cheese assumes first place. To carry the analysis some- what further by showing the correlation between water- content and certain factors, a tabulation of well-known varieties of typical groups is presented (Table III). In 86 THE BOOK OF CHEESE this table the series of typical dairy products are first arranged according to water-content of the final product. Approximate limits of percentages of milk-fat are also given, because milk-fat frequently affects texture to a degree almost equal to water. Column 4 gives the period within which the more quickly perishable cheeses are usable, and the length of the ripening for the more solid forms. The correlation between water-content, texture and the time of keeping is clearly shown for most varieties. TABLE III CORRELATION WATER- AND FAT-CONTENT WITH RIPENING VARIETY op PER CENT WATER PER CENT FAT PERIOD REQUIRED RIPENING AGENT Cheese: Soft, Cottage .... 70 trace a few days Bacteria Skim Neufchatel . 70 trace a few days Bacteria Neufchatel . . . 50-60 12-28 a few days Bacteria Camembert . . . 50 22-30 3-5 weeks Molds Cream cheese . . 40-50 35-45 a few days Primarily bacteria Semi-hard : Limburger . . . 40-45 24-30 3-6 months Bacteria Roquefort . . . 38-40 31-34 3-6 months Mold Brick 37-42 31-35 3-6 months Bacteria Hard: Cheddar .... 30-39 32-36 6-12 months Bacteria Swiss 31-34 28-31 9-18 months Bacteria and yeasts Parmesan . . . 30-33 2-3 years Bacteria The soft cheeses are quickly perishable products. Bacteria and molds find favorable conditions for growth CLASSIFICATION 87 in products with 45 to 75 per cent of water. If such growth is permitted, enzymic activities follow quickly with resultant changes in appearance, texture, odor and taste. Refrigeration is necessary to transport such cheeses to the consumer, if properly ripened. Trade in these forms may continue throughout the year in cool climates and in places where adequate refrigeration is available. Practically, however, outside the large cities this trade in America is at present limited to the cold months; inside the large cities much reduced quantities of these cheeses continue to be handled through the year. In the stricter sense, the soft group of cheeses falls naturally into two series: (1) the varieties eaten fresh; and (2) the ripened soft cheeses. Those eaten fresh have a making process which commonly involves the develop- ment of a lactic acid flavor by souring, but no ripening is contemplated after the product leaves the maker's hands. In the ripened series, after the making process is completed, the essential flavors and textures are de- veloped by the activity of micro-organisms during ripen- ing periods varying in length but fairly well-defined for each variety. In contrast to the soft cheeses, the hard kinds are low in water-content, ripen more slowly and may be kept through much longer periods. They retain their form through a wider range of climatic conditions. They develop flavor slowly and correspondingly deteriorate much more slowly. Such cheeses are in marketable con- dition over longer periods. In their manufacture the cooking of the curd takes a prominent place. 109. Relation of heat to classes. — The close relation between the heat applied and the product sought forms the basis of a striking series of graphs (Fig. 12, page 78). 88 THE BOOK OF CHEESE These show the changes hour by hour in the heat relation during the making process of a series of widely known forms, each of which is chosen as typical. In some of these forms, heat is applied but once to bring the milk to the renneting temperature typical for the variety. Subsequent manipulations are accompanied by a steady fall in temperature. In other forms, the curd when solid is specially heated or " cooked " to bring about the changes characteristic of the variety. These con- trasts are clearly brought out by the graphs which rep- resent practices well recognized for the varieties. The detailed process for these groups is considered in suc- ceeding chapters. CHAPTER VII CHEESES WITH SOUR-MILK FLAVOR THE cheeses with flavor of sour milk are probably more widely used than any other group. Historically and to a very large degree at present, they are farm cheeses.1 No estimate of volume of such production in the house- hold has ever been made. The utilization of surplus milk in this way is of ancient origin. With the introduction of the factory system of han- dling milk, the manufacture of such cheese in the house- hold was largely dropped. The rise in price of all food substances and increasing appreciation of the food value of milk products have made the recovery of all surplus milk in some form very necessary. The manufacture of cottage, Neufchatel and cream cheese is one of the best forms of such recovery which may be adapted to utilize any grade from skimmed-milk to cream. Large quantities of skimmed-milk have frequently been lost from the total of human food by the manufacture of casein for industrial uses, and by use as stock feed. 110. Skim series. — The kinds of cheeses eaten fresh have in common a very soft texture and the flavor of 1 Frandsen, J. H., and T. Thorsen, Farm cheese-making, Univ. Neb. Ext. Serv. Bui. 47, pages 1-16, 1917. Michels, J., Improved methods for making cottage and Neufchatel cheese, N. C. .Exp. Sta. Bui. 210, pages 29-38. Fisk, W. W., Methods of making some of the soft cheeses, Cornell Exp. Sta. Circ. 30, pages 41-62, 1915. 89 90 THE BOOK OF CHEESE sour milk, principally lactic acid. The group falls natu- rally into two sections : (1) the cheeses made from milk curdled by souring ; (2) those for which the milk is curdled by souring and rennet. In the latter group both agencies are necessary to the resulting product. The time required to curdle by souring alone is longer than when rennet is used; this period is usually longer than necessary for the cream to rise by gravity; hence the cream is either skimmed off or removed with the separator beforehand. The curd, therefore, is essentially a skimmed-milk curd. Casein curdled in this way tends to become granular or " rough," to feel " sandy " when rubbed between the fingers. Heating is commonly necessary to lower the water-content of the mass even to 75 per cent. Such curd tends to become hard or rubbery when heat is ap- plied. In this group, the best known form is variously called " cottage " cheese, " clabber " cheese, schmier- kase. 111. Cottage cheese is made from skimmed-milk, soured by lactic bacteria until a curd is formed. This is done preferably at about 20° C. (70° F.), because at this temperature the purely lactic type of organism has been found to outgrow competing forms which may be present. Starter containing the desired culture, if prop- erly used, saves much time in the curdling period. Such curdling requires at least twelve to twenty-four hours, frequently much longer unless abundant starter is intro- duced. 112. Household practice. — The details of cottage cheese making in the home differ widely in separate sec- tions and even in different families in the same part of the country. The essentials of the practice, common to all, include : (1) curdling the whole milk by natural CHEESES WITH SOUR- MILK FLAVOR 91 souring; (2) removing the sour cream which is usually used for butter-making ; (3) scalding the curdled skimmed- milk either by slowly heating it in the original vessel surrounded by hot water or by actually pouring an approximately equal volume of boiling water into the curdled mass; (4) bagging and draining the mass until it reaches the desired texture; (5) the kneading of the mass with the addition of salt and cream. The result- ing product varies greatly in quality. Unfavorable fer- mentations frequently affect the flavor.1 The " scalding " varies from a temperature of 90° F. almost to boiling with a resultant texture varying from almost the smooth buttery consistency of Neufchatel to hard coarse granular lumps. The best practice, using clean well-cared-for milk and draining at low temperature, produces a very attractive cheese. Such cheese is heated to 90° to 100° F. on the maker's judgment, drained carefully, kneaded well by hand or by machine with the addition of cream to give it an attractive texture and flavor. 113. Factory practice. — When cottage cheese is made in the factory,2 separated milk is taken; it should be pasteurized and then soured by a lactic starter. The souring can be accelerated by the use of a starter, which may be added at the rate of 0.5 to 5 per cent of the skimmed-milk used, depending on the amount of starter that can be made. Generally, the more starter added, the more rapid will be the coagulation and the better will be the flavor of the cheese. As soon as the milk has thickened, the curd is ready to be broken up and 1 Tolstrup, R. M., Cheese that farmers should make, Iowa Agr. 15 (1914), 2, pages 89-90. 2 Van Slyke, L. L., and Hart, E. B., Chemical changes in the souring of milk and their relations to cottage cheese, N. Y. (Geneva) Exp. Sta. Bui. 245, pages 1-36, 1904. 92 THE BOOK OF CHEESE separated from the whey. This separation is hastened by the application of heat. Usually the temperature of the curd is raised slightly before it is broken up ; since this makes the curd firmer, there will be a smaller loss of curd particles in the whey. The curd may be cut with coarse Cheddar cheese knives or broken with a rake. The temperature of the curd should be raised very slowly, at least thirty minutes being taken to reach the desired final temperature. No set rule can be given as to the exact temperature to which the curd should be heated. The temperature should be raised until a point is reached at which the curd, when pressed between the thumb and the fingers, will stick together and not go back to the milky state. This temperature is usually from 94° to 100° F., but the cheese-maker must use his own judgment in this respect. If the curd is heated too much, it will be hard and dry ; on the other hand, if it is not heated sufficiently, the whey will not separate from the curd and the latter will be very soft and mushy. When the curd has been heated sufficiently and has become firmed in the whey, it should be removed from the whey. This may be done either by letting down one end of the vat and piling the curd in the upper end, or by dipping out the curd into a cloth bag and allowing the whey to drain, which it does very rapidly. No treatment can prevent the " roughness " of an acid curd (this is a fine gritty feeling when rubbed between the fingers), but the coarse hard grainy texture and lumps charac- teristic of the highly heated curd do not develop. Experimental workers have agreed that to have the proper texture, such curd should contain when finished about 70 to 75 per cent of water. It should have a mild but clean acid flavor. Such a cheese will carry about 1 CHEESES WITH SOUR-MILK FLAVOR 93 to 2 per cent of salt, without an objectionably salty taste. This cheese is commonly sold by measure, some- times in molds or cartons. The manufacture of all forms of cottage cheese has been largely superseded by the making of skimmed-milk Neufchatel or Baker's cheese. The yield from one hundred pounds of skimmed-milk runs up to fourteen to nineteen pounds of cheese, when made very wet or from pasteurized milk. The yield varies with the moisture-content of the cheese, being greater for cheese with a high content. Too much moisture or whey should not be left in the curd, how- ever, as this will render it too soft to be handled. Cottage cheese made by either the home or factory practice is a quickly perishable article. Although the acid restrains bacteria at first, the high percentage of water favors the growth of molds which tolerate acidity, especially Oidium (Oospora) lactis and the Mucors • or black molds. These molds destroy acidity rapidly and thus permit the bacteria of decay to develop and to produce objectionable taste and odors. Spoilage in these products is accelerated by the kneading process which distributes air throughout the mass and with it all forms of microbial contamination. 114. Buttermilk cheese. — A cheese closely resembling cottage may be made from buttermilk. If the buttermilk came from cream which was churned before it became sour, the process is the same as that already described for the making of cottage cheese from skimmed-milk. If the buttermilk came from sour cream the process of manufacture is much more difficult. The casein of sour cream has already been coagulated with acid and broken during churning into very minute rather hard particles. These fine particles are difficult to recover. They are so 94 THE BOOK> OF CHEESE fine that they pass through the draining cloth or at other times clog it and prevent drainage. They do not stick together at ordinary temperatures. They cannot be collected by the use of acid because they have already been coagulated with acid. After casein has been coagulated with acid, rennet extract will not recoagu- late the particles. The buttermilk may be mixed with sweet skimmed-milk ; then as the latter coagulates, it locks in the casein of the buttermilk so that it can be collected. If buttermilk from soured cream is used alone, the casein may be collected1 by neutralizing and heating to 130 to 150° F., and holding until the casein gathers together. The whey can then be drawn off. Often there is further difficulty in getting the casein to collect, since the pieces remain so small that they go through the strainer. Cheese made entirely from buttermilk is sandy in texture and often not palatable. If the buttermilk with good flavor is mixed with skimmed-milk, it makes a good cheese closely resembling cottage. 115. Neufchatel group.2 — The Neufchatel process originated in northern France where a number of varieties are included under this as a group name. Among these are Bondon, Malakoff, Petit Suisse, Petit Carre. The name designates a general process of curd-making which is applied to skimmed-milk, whole milk or cream. Some of the resultant cheeses are ripened ; some are eaten fresh. The Neufchatel cheeses of France gained such wide recog- nition for quality that the process of making has become widely known. In America the manipulations of the 1 Sammis, J. L., Three creamery methods for making butter- milk cheese, Wis. Exp. Sta. Bui. 239, 1914. 2Matheson, K. J., C. Thorn and J. N. Currie, Cheeses of the Neufchatel group, Conn. (Storrs) Exp. Sta. Bui. 78, pages 313-329, 1914. CHEESES WITH SOUR-MILK FLAVOR 95 French process were early dropped. The essentials were made the basis of a successful factory practice which has been widely adopted. TJie American factory prac- tice is discussed here and the French process briefly considered under the heading Ripened Neufchatel. (See Chapter VIII.) 116. Domestic or American Neufchatel cheeses are soft, have clean sour milk (lactic acid) flavor and are quickly perishable. In all but the coldest weather, they require refrigeration to reduce deterioration and loss. They range in fat-content from traces only to 50 per cent and more ; in water from 40 to 75 per cent, accord- ing to the milk used. In texture Neufchatel is smooth, free from gas, free from lumps or roughness when rubbed between the fingers. This flavor and texture is obtained by a combination of slow rennet curdling with develop- ing acidity. No further ripening is permitted. 117. The factory. — Neufchatel factories require the standard dairy equipment for receiving, weighing, testing, separating, heating, pasteurizing and cooling the milk. Since many factories produce several products, the same general dairy equipment may serve for all. In addition to such equipment, Neufchatel requires a cur- dling apparatus which can be held at 70-75° F. This may be a room properly controlled, or a tank where tem- perature control is obtained by water and steam. For draining, a room kept at 60° F. gives nearly the ideal temperature, which must be supplemented by relative humidity high enough to prevent the exposed surface of curd from drying during periods of twelve to twenty-four hours. This requires almost a saturated atmosphere. A room with special molding machinery is required and tables for wrapping, labeling and boxing the product 96 THE BOOK OF CHEESE CHEESES WITH SOUR-MILK FLAVOR 97 are necessary. Box-making machinery is usually an economic necessity for work on a large scale. Adequate refrigeration is requisite both to chill the curd before molding and to preserve it after packaging. 118. Cans. — For curdling, the " shot-gun " can, about nine inches in diameter and twenty inches deep, is gen- erally used. This holds thirty to forty pounds of milk. Increased capacity is dependent, therefore, on the number of units installed, not on changes in the units themselves. 119. Draining racks. — A draining rack is required for each can of curd. These racks also are standardized units whose num- ber limits the capacity of the factory. The de- sign of these racks (Figs. 13, 14) and their ar- rangement in the draining room are taken from Bul- letin 78 of the Storrs Agricul- „ . FIG. 14. — Detail of a Neufchatel draining rack. tural Experiment Station : " The racks are rectangular, thirteen inches wide, thirty-six inches long and ten inches deep. The corner posts extend one and one-half inches beyond the strips at top and bottom with the tops rounded as a rule as seen in the photograph. The bottom slats fit loosely into notches, hence are removable for washing purposes. The materials required are four corner posts one and one-half by one and one-half inches; nine strips one by three-eighths by thirty-six inches ; six strips one by three- 98 THE BOOK OF CHEESE eighths by thirteen inches, two strips one by three-eighths by twelve and a quarter inches, notched to receive the bottom slats; all made from pine." 120. Cloths. — For each draining rack, a cloth one yard wide and one and one-half yards long is required. Cotton sheeting is satisfactory for the purpose ; " even- count, round-thread, unmercerized voile " is suggested by Dahlberg.1 121. Molding machinery. — For work on a large scale, special power machines 2 are regularly used. These consist of a hopper and worm delivering a standard size stream of curd through a proper size and shape of delivery tube. This curd stream is cut by an automatic device into the proper lengths to form the standard cheese. In this way a uniform size of cheeses is obtained. Experi- mental work with hand apparatus showed that a worm six inches in diameter is required to deliver curd in a smooth column one and one-half inches square. If the pressure is not sufficient, 1 Dahlberg, A. 0., The manufacture of cottage cheese in creameries and milk plants, U. S. Dept. Agr. Bui. 576, pages 1-16, 1917. 2 Since the number of factories has continued small, the manu- facture of this type of machine has remained a monopoly in which each machine is made to order by the Van Eyck Machine Co. of Holland, Mich. FIG. 15. — Neuf chattel and cream cheese molds. CHEESES WITH SOUR- MILK FLAVOR 99 the column will frill at the edges. Such irregular surfaces cannot be wrapped smoothly enough to delay spoilage. On a small scale, a fair grade of product can be molded through a tin tube (see Fig. 15) one and three-quarters inches in diameter and ten inches long in which the curd is compressed by a close fitting plunger operated by hand. 122. Milk for Neufchatel should be clean, free from gas and taint. Such milk should preferably be not more than twelve hours old when received and in no case show higher than 0.20 per cent lactic acid by titration. Milk testing 4 per cent fat or higher will produce a higher qual- ity of product than lower grade milk, although every grade from skimmed-milk to cream is used in producing some form of Neufchatel. This milk should be pasteur- ized unless shown to be free from tuberculosis by proper test of the cattle. Evidence 1 that the organism of tuber- culosis will withstand the regular handling process for cheeses of this group, and retain its ability to cause dis- ease in experimental animals makes the introduction of pasteurization necessary in this whole group of cheeses. Any effective pasteurization may be used, but tempera- tures of 140-145° F. for thirty minutes have been effective with less changes in the milk than higher tem- peratures for shorter periods. The milk should be cooled to curdling temperature and the starter and rennet added and stirred into the milk in bulk. The milk may then be quickly distributed into the curdling cans with a hose or from the gate valve of the mixing vat. 123. Starter. — To insure the development of a clean acid flavor, a small amount of lactic starter should be 1 Presented by Dr. E. C. Schroeder of the U. S. Dept. Agr. to the International Association of Dairy and Milk Inspectors, at Washington, Oct. 17, 1917, published Jour. Am. Vet. Med. Assoc'n 52, N. S. 5, no. 6, pages 674-685, 1918. 100 THE BOOK OF CHEESE used. The quantity to use depends on the quality of the milk. With skimmed-milk, a pint for each thirty-pound can is recommended by Matheson and Cammack 1 and by Dahlberg. (See page 98.) For whole-milk Neufchatel, 2 c.c. to a thirty-pound can of milk commonly gives good results. On this basis 2 ounces of starter would be suf- ficient if properly stirred into about 1000 pounds of milk. Too slow development of acid is preferable to over-rapid souring. 124. Renneting or setting. — The milk should be cooled after pasteurizing to between 70° and 75° F. Ren- net is added at the rate of f c.c. to a thirty-pound can (roughly J ounce to 1000 pounds). This will thicken the milk sufficiently in the first few hours to reduce the separation of the cream. For completion of the curdling and souring process, twelve to eighteen hours are required. Usually the cans stand overnight at uniform temperature. When ready to drain, the curd should be firm, smooth and mildly acid. Whey separating from it should not titrate above 0.35 per cent titrated as lactic acid. 125. Draining. — A cloth is spread over a draining rack and the contents of one " shot-gun " can poured upon the cloth with as little breaking as possible. In this way a large surface is exposed. The room must be kept wet to prevent the surface of the curd drying to form crusts which stop draining. A temperature of 60° F. is favorable to the maintenance of proper texture and humidity without the development of objectionable organisms, especially Oidium lactis, which tends to cover every exposed surface in such rooms. Draining may be 1 Matheson, K. J., and F. R. Cammack, How to make cottage cheese on the farm, U. S. Dept. Agr., Farmers' Bui. 850, pages 1-15, 1917. CHEESES WITH 8OV&MIJ&R hastened by turning the curd or changing the position of the cloth. In factory practice, the large draining surface reduces the necessity of handling the curd and reduces the loss of fat. About twelve hours are required upon the draining racks. On a small scale with a few cans of curd in the home, any form of draining rack may be used, such as a potato or berry crate, or the corners of the cloth may be brought together, tied and the mass hung up. The curd must be turned by pulling up the corners of the cloth to prevent drying at the edges and stoppage of draining from the center of the mass. Such treatment produces much more rapid drainage than the factory practice and involves proportionately more labor and larger fat losses. 126. Cooling Neufchatel. — When whey ceases to separate readily, the corners of the cloth are loosed from the rack, folded diagonally or tied, and the curd cooled on ice or in refrigerators. When thoroughly chilled the bags of curd are put into presses, where light but in- creasing pressure forces more whey out of the mass. Tests at this time should show about 0.60 per cent acid in the whey. With low-fat curd every step of the process may be hastened, but with high-fat care must be exer- cised to prevent loss of fat during pressing especially. Any pressing device permitting continuous pressure with ease of manipulation may be used. 127. Pressing. — The ideals of the maker must deter- mine the extent of pressing. A high yield is obtained by leaving whey in the curd. If immediate consumption is certain, such cheese may be satisfactory, but if the cheese is to be held some days the extra whey carrying more milk-sugar favors increased acid development. This produces very sour cheese with much more danger 102 THE BOOK OF CHEESE of other fermentations which cause objectionable flavor. Too much water favors more active bacterial growth as well as produces cheese too soft for the necessary handling in the market. In the press, several bags of curd may be piled together. The press should be released and the bags turned from time to time to insure even drainage. Several hours of pressing are usually required. The danger of insufficient pressing is due to the difference of texture between the worked and unworked curd. Before working, curd carry- ing 10 per cent excess moisture resembles the finished product sufficiently to deceive any but the experienced maker. But if this curd is transferred to the worker and to the molding machine, it is found to become soft, pasty and sticky, to lack "body," hence to make very unsatis- factory packages and to spoil very quickly. The masses of curd should come out of the press as dry and hard flat cakes. 128. Working and salting Neufchatel. — The cakes of curd go from the press to the working table. Here they are broken by hand or by a butter- worker or kneading machine (Fig. 16). Salt at the rate of one and one- half pounds to 100 pounds of curd is added. If the FIG. 16. — Working Neufchatel. CHEESES WITH SOUR-MILK FLAVOR 103 curd is not sufficiently pressed, the masses become mushy or pasty during the working process. The work- ing is continued until the whole mass is uniformly smooth and buttery. 129. Storage. — The draining and working processes permit the contamination of the curd with organisms from the air and from the apparatus. These are dis- tributed throughout the mass. Air is also worked thoroughly into the curd. Such a product spoils quickly. Distributing houses find the Neufchatel trade uncertain in volume from day to day, hence many of them store the cheese in bulk and package only fast enough to fill orders. This minimizes the loss due to spoilage. Such curd may be packed into tubs and kept for considerable time in cold storage. If molded for the retail trade, it is more quickly perishable. When packed solidly in mass, curd is largely protected from spoilage by the ex- clusion of air and perhaps the quick exhaustion of free oxygen through the respiration of the micro-organisms present and by its acidity. This must be supplemented by low temperature to reduce the loss to a minimum. Even when spoilage begins, it is easily confined to the slight growth of Oidium lactis or green mold and bacteria on exposed areas. These can be removed with minimum loss and damage to the mass. On the other hand, such curd molded into the commercial package of 3 to 6 ounces and wrapped in paper, with tin-foil or carton for protection, still presents enormously increased surface for the growth of aerobic forms — especially Oidium lactis, green mold (Roquefort mold is the usual green species) and accompanying bacteria. Curd in tubs may be kept some days; in commercial packages lowering of quality (flavor) begins almost at once. 104 THE BOOK OF CHEESE 130. Molding. — When the standard molding ma- chine (Fig. 17) is provided, curd is brought directly from the refrigerator to the machine. If permitted to be- come warm, the mass becomes sticky; when cold it is more readily handled. The machine is fitted with the special delivery tube for the variety to be handled, cylindrical for Neufchatel in its various forms, rectangular in section for cream. Enough workers should be pro- vided to wrap and label the cheese without leaving it FIG. 17. — Molding Neufchatel. exposed to contamination or heat. Parchment paper and tin-foil cut the proper size for each variety and bear- ing printed labels are readily obtainable. Each cheese should be wrapped with paper and tin-foil and put directly into a flat box which holds a standard number (usually 12 or 24) of the special product. In working with the hand molding tube (Fig. 15) the same care is required. Chilled curd is forced into a firm smooth mass with the plunger. It is removed CHEESES WITH SOUR-MILK FLAVOR 105 and wrapped when it reaches the regular size of the variety. All forms when molded go directly into the boxes and then back to the refrigerators until demanded for actual use. The details of the process differ according to the form made. 131. Skimmed-milk Neufchatel. — Separator skimmed- milk is frequently made into curd by the Neufchatel process. The absence of fat eliminates the largest element of loss in manufacture. Each stage of the making process, therefore, may be shortened. The demand that the curd shall be smooth and buttery in texture rather than rough or gritty requires the exercise of care in curdling of milk. The draining and pressing of the curd may be accomplished much more rapidly than in the fatty cheeses. The final product should differ from cottage cheese in smoother texture, milder acidity and, as a rule, cleaner flavor. In composition, the absence of fat must be largely compen- sated by leaving more water in the cheese. Such a product reaches the market with 65 to 75 per cent of water and perhaps 1.25 per cent of salt. Casein forms 20 to 30 per cent of the mass. These cheeses are very perishable on account of their high water-content. The destructive effect of micro- organisms both in the interior of the cheese and upon its surface is rapid. Cheeses of this description may be found in the trade as cottage cheese, Neufchatel style, and as Neufchatel made from skimmed-milk ; skimmed-milk Neufchatel would be a strictly proper labeling. 132. Baker's cheese. — There is considerable market for skimmed-milk curd as Baker's cheese. This product is essentially skimmed-milk Neufchatel curd, partially 106 THE BOOK OF CHEESE drained and sold in bulk. When the bakery is near by, the curd is frequently shoveled into milk-cans in very wet condition and sent directly from the factory to the bakery. If the distance is such as to require considerable time for transportation, the same care is frequently given as for Neufchatel curd packed in bulk for storage and transportation. Great variations in practice are found among the makers of this type of product. In some cases low grade skimmed-milk is handled on a large scale. Curdling is done quickly and little care is given to the details of flavor and texture in the curd. Working in this manner, two men are able to make a ton of such curd, and ship it out in milk-cans each day. The resulting product, although very deficient in flavor and texture, goes into manufac- tured specialties which conceal its deficiencies if con- sidered as cheese. 133. Domestic Neufchatel. — The name Neufchatel, unless limited clearly by the label, should designate a cheese made from fresh whole milk. Cheeses of this group are produced in a small number of well-equipped factories scattered widely through the dairy states of the North and Northeast. Every factory uses one or more trade names for its product. The same product is frequently relabeled by the distributor who uses his own trade name instead of that of the maker. The usual form of package is cylindrical, about if inches in diameter and 2^ inches long, or sometimes rectangular 2^ by 1| by 1^ inches. The cheese is pro- tected by wrapping in parchment paper closely surrounded by tin-foil. These packages vary from 2^ to 4 ounces. In some cases screw-topped glass jars are substituted for the tin-foil package. They are objectionable, first, be- CHEESES WITH SOUR-MILK FLAVOR 107 cause of cost and, second, because they are so commonly associated with less perishable products as to mislead either dealer or consumer into holding the product for too long a time. The paper or tin-foil package can be kept only at refrigerator temperature, hence automat- ically keeps its possessor reminded of the perishable nature of its contents. Neufchatel of the best quality made from whole milk testing about 4 per cent fat may be expected to fall within the following limits ; 1 many grades contain more water than this at the expense of flavor and keeping quality : Water 50-55 per cent Fat 23-28 per cent Casein 18-21 per cent Salt . , 0.5-1.25 per cent Yield 12-14 Ib. per 100 Ib. of milk. 134. Partially skim Neufchatel. — Brands of Neuf- chatel made from milk that would test every gradation from whole milk to separator skimmed-milk may be found. The quality of the product varies with the skill of the maker from brands no better than cottage cheese to products scarcely distinguishable from the best whole- milk Neufchatel. Many factories that produce more than one quality of Neufchatel use labels of different color, different design or both to separate them; for example, blue labels usually stand for whole milk, red labels represent lower grades. Sometimes the difference in material is indicated by a clear cut grade mark. Fre- quently color, a design of label or both are the only definite marks upon the cheese. The consumer un- familiar with the trade practice commonly has no means of knowing the quality of the product offered. Such 1 Taken from Conn. (Storrs) Exp. Sta. Bui. 78, page 328. 108 THE BOOK OF CHEESE cheeses vary in water-content from 55 to 70 per cent; in fat from 10 to 25 per cent; in casein from 18 to 25 per cent. 135. Cream cheese. — The Neufchatel process is also used to make cream cheese. The material utilized is commonly what has been called double cream. This is produced by separating about half of a given volume of milk and running the cream into the other half. Usually cream cheese is made in the same factory as various grades of Neufchatel. No material is lost. In some instances, cream cheese is prepared by working thick cream into the Neufchatel type of curd from practically skimmed-milk. In working with high percentages of fat in curd, care must be taken to avoid loss of fat in draining and pressing. The curd is carefully chilled before press- ing to reduce this loss. This may be done under refriger- ation or upon cracked ice. Otherwise the manipulations of the process are unchanged. The cheeses are commonly molded in the Neufchatel machine into square cakes weighing about 4 ounces and measuring approximately 3 by 2 J by | inches. These are wrapped in paper and tin-foil and handled exactly as Neufchatel. Cream cheese of high quality made from reenforced milk testing 7 to 9 per cent fat may be expected to test approximately as follows : l Water 38-43 per cent Fat 43-48 per cent Protein 13-16 per cent Salt 0.5-1.25 per cent Yield 16-18 Ib. per 100 Ib. of cream. Increases of water, hence greater yields, are very com- mon but usually associated with loss in quality both as 1 Taken from Conn. (Storrs) Exp. Sta. Bui. 78, page 328. CHEESES WITH SOUR-MILK FLAVOR 109 to flavor and texture, and in more rapid spoilage ; certain brands regularly carry 50 to 60 per cent of fat but their increased cost of manufacture and sale restricts them to the role of specialties with closely limited distribution. Trade names such as Philadelphia Cream, Cow Brand, Eagle Brand, Square Cream, Blue Label and many other factory brands are on the market. 136. Neufchatel specialties. — Neufchatel or cream cheese curd is frequently mixed with some flavoring substance, such as pimiento (pickled Spanish peppers), olives, nuts, spices or other cheeses, such as Roquefort. These bear appropriate trade names and form a very attractive addition to our varieties of cheese. Among the names found are Pimiento, Olive, Nut, and Pirn-olive or Olimento. 137. Gervais is a brand of cream cheese made in Paris and sold widely in France and even in other continental countries. It occasionally comes to America. As made in Paris, these cheeses are flat cakes containing approx- imately 40 per cent water and 35-45 per cent fat. It clearly differs only in detail from the square cream cheeses made in America. The name Gervais is the property of a particular company. Since the cheese differs in no essential feature from other cream cheeses, this name should not be applied to a domestic cream brand. 138. European forms occasionally imported. — Among the cheeses related to Neufchatel as they reach the market are the " White " cheeses of southern Europe. These differ greatly in quality according to their source and to their content of cow, sheep, goat's milk or some com- bination of these. This texture and flavor link them with unripened Neufchatel. The time required for importation puts a minimum possible period of ten to fif- 110 THE BOOK OF CHEESE teen days between production and consumption with a probable period of at least one month for most samples. As they come to America, these forms usually show fermentive changes beyond those tolerated in the do- mestic product. This may take either of several forms : (1) intensification of acid flavor with the intensification of the characteristic flavors of the particular brand; (2) the development of old or rancid flavors ; (3) the de- velopment of Oidium and partial softening of the mass through its agency; (4) the growth of Roquefort mold and development of the flavor associated with that organism. This last form was found in a shipment of Hungarian Briuse which showed about 40 per cent fat, 14 per cent protein and 43 per cent water. CHAPTER VIII SOFT CHEESES RIPENED BY MOLD THE ripened soft cheeses include a series of groups of varieties which, in addition to initial souring, have been subjected to special ripening processes, and which in the ripened condition are soft in texture and mostly have high flavors. The varieties in each group have in com- mon some essential principles of manufacture together with a ripening process dominated by a characteristic group of organisms. In certain groups, the ripening is dominated by a yellowish or orange viscid surface slime containing Oidium lactis and bacteria; in another series, the characteristic organism is a mold of the genus Pen- icillium (P. Camemberti). Referring to the analysis of groups (page 83), the ripened soft cheeses are found to fall into three well-marked groups, one of which may per- haps be subdivided as indicated. The series curdled by souring alone begins with approximately cottage cheese curd and develops high flavors by ripening, as in " hand " cheese. Ripened Neufchatel curdled by souring and rennet together finds its basis in Neufchatel curd also but modifies the final product until the familiar flavor and texture of the unripened form are no longer recogniz- able. Among the forms curdled by rennet alone the Camembert series contains one form, Coulommiers, which is occasionally used unripe, but represents in general a mold-ripened group of highly flavored forms. The series 111 112 THE BOOK OF CHEESE of soft rennet cheeses ripened by bacteria may be broadly designated the Limburger group. 139. Hand cheese and its allies. — Among skim cheeses, there is a series of forms largely German in origin in which curd not far removed from cottage cheese is the basis of the product. Harz cheese "is one of the best-known of these forms as studied by Eckles and Rahn.1 One of these forms, hand cheese,2 is manufactured on a commercial basis in farm dairies among families of German descent principally in Pennsylvania, and on a factory basis in a few places in New York, northern Illinois and Wisconsin. On the small scale, curd is made by natural souring or by use of starter, heated to expel water, cooled and molded by hand into cakes two to three inches in diameter and one-half to three-quarters inch in thickness. The freshly formed cakes are placed upon a shelf to dry. There they are turned daily until fairly firm, then packed in rolls into wooden boxes and ripened in a cool damp room. In this ripening there is a prompt development of a heavy viscous slime, which consists of Oidium and bacteria. Other molds forming loose cottony mycelium are brushed off if they appear. The proper consistency of this slimy covering depends on a close adjustment of water-content in the cheese with tempera- ture and relative humidity in the ripening room. If conditions are too dry, the cheeses harden quickly or if less dry they are attacked by green or blue-green molds. If too wet, the slimy covering becomes too soft and watery, or secondarily covered with loose shimmering masses of 1 Eckles, C. H., and O. Rahn, Die Reifung des Harzkases, Centralb. f. Bakt. etc. 2 abt. 14 (1905), pages 676-680. 2 Monrad, J. H., Hand cheese, N. Y. Produce Rev. etc. 25 (1908), 16, page 644. SOFT CHEESES RIPENED BY MOLD 113 mold (Mucor sp.). Ripening should proceed slowly and occupy a period of six to eight weeks. 140. Pennsylvania pot cheese. — A form of " pot " cheese is made in certain counties of Pennsylvania, prin- cipally for local use. Production of this cheese on a fac- tory basis is now being attempted. The steps in manu- facture are about as follows : * (1) The home-made type of cottage cheese curd is prepared, put into a crock or pot and covered carefully; (2) kept in a warm place (in kitchen usually) ; (3) stirred from time to time, until it has ripened to a semi-liquid condition. This occurs very rapidly under the attack of Oidium lactis accompanied by bacteria. Within a period of three to seven days, according to the temperature and to the water-content of the mass, the granules of curd become covered with a wrinkled gelatinous almost viscid mass of mold mycelium beneath which is a layer of semi-liquid curd with a strong characteristic odor and taste. This ripened or semi- liquid part reaches about half the total mass in four or five days at favorable temperatures. (4) The vessel is then placed in a larger vessel of water and heated over the fire with constant stirring until the whole mass is melted and smooth. (5) Butter or cream, and salt or other flavor is finally added, stirred in and the liquid cheese poured into molds or jelly glasses to cool. If properly made and cooked, the resultant cheese has a soft buttery consistency with an agreeable flavor, which frequently resembles that of Camembert cheese. 1 The authors are under obligations to Mrs. E. E. Kiernan for her description of this process (in the Somerset County Leader, Jan. 10, 1908) and her letters concerning it. The statement of the process given here combines the published statement with the results of our own experiments. 114 THE BOOK OF CHEESE 141. Appetitost (Appetite cheese). — A Danish butter- milk cheese is made under this name. Sour buttermilk is heated, by some to boiling temperature but others (Monrad l) prefer 120° F., stirred thoroughly and allowed to settle. The whey is removed as far as possible. The semi-liquid mass is covered and set in a warm place. Fermentation becomes active. This tends to make the curd more viscous or sticky. It is then kneaded and allowed to ferment again. This process is repeated until the mass is yellowish and soft but tough or viscous. When thoroughly fermented, the mass is again heated to 120° F., and 6 per cent salt is added together with spice ; both are worked in and the cheese is formed into fancy shapes for sale. 142. Ripened Neufchatel, French process. — Neuf- chatel as a ripened cheese is made rather widely in France but it is produced on an especially large scale in Seine- Inferieure.2 Some factories use whole milk, or milk with added cream, others skimmed-milk.3 The whole-milk brands of Neufchatel are those which have the widest reputation. For making this cheese, the working room is held as closely as possible at 15-16° C. (58-60° F.). The milk is strained into earthen vessels holding twenty liters. Rennet is added to the freshly drawn milk at about 30° C. (86° F.) in amount sufficient to produce coagulation in about twenty-four hours. Draining racks 1 Monrad, J. H., Appetitost, N. Y. Produce Rev. etc. 25 (1908), 16, page 644. 2 Pouriau, A. F., La Laiterie, sixiSme ed. par Marcel Mon- teran, page 453, Paris, 1908. 3 Among the varietal names for Neufchatel cheese from whole milk or with added cream are Petits Bondons, Malakoffs, Carres affines. Among low fat or skim forms, Petit Suisse, Gournay. SOFT CHEESES RIPENED BY MOLD 115 of various forms are covered with cloth. The vessels of curd are dumped upon the racks. The whey separates slowly and drains off through the cloth. About twelve hours are allowed for this process. The corners of the cloth are then brought together and folded in or tied and the mass pressed to complete the drainage. The finished curd is worked or kneaded to produce a smooth and uniform texture. This process of curd-making is essen- tially the same as the American factory process of making Neufchatel. The ripening process has been entirely dropped in America. The curd is finally molded in metal forms 5 cm. (2 inches) in diameter and about 6.7 cm. (about 3 inches) high, open at both ends. These molds are filled, the freshly formed cheeses are pressed out with a plunger or piston and their surfaces smoothed with a wooden knife. After molding is completed, the cheeses are salted by sprinkling the entire surface with fine dry salt as the cheese is held in the hand. In this way each cheese re- ceives and absorbs 3 to 4 per cent salt. After salting, the cheeses are arranged upon boards and allowed to drain twenty-four hours. They are then removed to the first or drying room. The frames of the drying room (secherie) are covered with straw and the cheeses are placed care> fully upon the straw to avoid contact with each other. They are turned each day to present a fresh surface to the straw during a period of two to three weeks in the drying room (secherie). Mold begins to show as white cottony mycelium after five to six days, and slowly turns to "blue" (bluish green). When the cheeses are well covered with this moldy rind, they are removed to the ripening cellar. In the ripening cellar also the cheeses stand upon straw. They are turned over every three or 116 THE BOOK OF CHEESE four days at first, then allowed to stand for a longer period. When ripe, a Neufchatel cheese so made weighs about 125 grams. One liter of milk makes 225 grams of such cheese. The ripening of Neufchatel has never been fully studied, but a series of these cheeses were obtained by one of the authors ; cultures were made and examined.1 The salt-content in the first place was found to be so high that Oidium lactis was eliminated as an active factor in the ripening. The mold proved to be on some cheeses Penicillium Camemberti, the typical mold of Camembert as it is made in Normandy, on others P. Camemberti var. Rogeri, the pure white form as used under the patents of M. Georges Roger in the region of Seine-et-Marne to the eastward of Paris and called by him and by Maze P. candidum. The physical condition of the ripened curd and the flavors encountered were those associated with these two species by many hundreds of experiments during the Camembert investigation in Connecticut.2 These facts justify the conclusion that ripened Neufchatel is first soured by lactic organisms, then so salted as to eliminate or reduce to a minimum the characteristic activities of Oidium lactis, while the proteolytic action and the physical changes are closely similar to those of Camembert which is ripened primarily by the same molds. 1 Thorn, C., J. N. Currie and K. J. Matheson, Studies relat- ing to the Roquefort and Camembert types of cheese, Conn. (Storrs) Exp. Sta. Bui. 79, page 392. 2 Full discussion of this product is found in U. S. Dept. Agr. Bur. An. Ind. Bui. 115. Camembert cheese problems in the U. S. also published as Storrs Exp. Sta. Bui. 58 with the same title. Also a supplementary paper in Bui. 79 of Storrs Exp. Sta. SOFT CHEESES RIPENED BY MOLD 117 143. The Camembert group. — The soft cheeses ripened by molds are French in origin. Their manufacture has spread into Germany, Italy and America. Of the series, the most widely known is Camembert, which will be described as typical for the group. Brie, Coulommiers, Robbiola and Ripened Neufchatel belong to this series. 144. Camembert cheese. — The origin of Camembert is given by French authorities as 1791 in the Commune of Camembert near Vimoutiers in Orne, France. From a very restricted production at first, Camembert-making has spread through the region from Caen in the west to Havre, Rouen and a considerable area east of Paris. In America Camembert began to be made in one factory about 1900. Several other factories followed by 1906. The difficulties and losses encountered led to the abandon- ment of these undertakings, until at the outbreak of the European war in 1914 but one factory was making Ca- membert and that only on an experimental scale. Mean- while the United States Department of Agriculture and the Storrs Experiment Station had taken up and solved, on an experimental basis, most of the problems arising in these commercial failures. A shortage of product at the outbreak of the war brought about the re-estab- lishment of a series of factories. The product as put on the market indicates that a permanent establishment of Camembert-making is entirely practicable. Camembert cheese is made from cow's milk either whole or very slightly skimmed ; the removal of about 0.5 per cent of fat has been found to be desirable if not actually necessary. 145. Description of Camembert.1 — These cheeses are made in sizes 2| to 4^ inches in diameter and li to 1^ 1 Thorn, C., U. S. Dept. Agr. Bur. An. Ind. Circ. 145 (1909), page 339. 118 THE BOOK OF CHEESE inches in thickness. They are ripened by the agency of molds and bacteria which form a felt-like rind over their whole surface, Tg- to J of an inch in thickness. This rind may be dry and gray or grayish-green, consisting of a felt-like surface of mold on the outside, below which a harder portion consists of mold embedded in partially dried cheese, or the moldy part may be more or less com- pletely overgrown or displaced by yellowish or reddish slime composed mainly of bacteria. Good cheeses may have either appearance. Inside the rind, the cheese is softened progressively from the rind toward the center from all sides, so that a fully ripe cheese has no hard sour curd in the center, but is completely softened. No mold should be visible inside the rind, but the moldy rind itself is necessary because the ripening is caused by the enzymes secreted by the organisms of the rind into the cheese. As the curd ripens, the changed portion assumes a slightly deeper color than the unripe curd as a result of chemical changes. Well-ripened cheeses vary from nearly a fluid texture to the consistency of moderately soft butter. The ripen- ing of Camembert is finished in wooden boxes which pro- tect the cheeses from breaking after they become soft and during the market period. 146. Conditions of making and ripening. — These pro- cesses depend on a very close adjustment between the com- position of the freshly made cheese and the temperature and humidity of the rooms in which the cheeses are made and ripened. Very slight failures in control bring loss in ultimate results. The room for making Camembert should be maintained between 60° and 70° F. and should be wet enough to reduce drying to a minimum. The essentials of apparatus are comparatively inexpensive. SOFT CHEESES RIPENED BY MOLD 119 Work on a factory basis calls, however, for the installa- tion of special tables and other apparatus to utilize space and labor to advantage. Rooms are protected from change of weather by double sash in the windows. Flies must be excluded by close-meshed screens for all doors 120 THE BOOK OF CHEESE and windows with movable sash. The equipment in- stalled in such a room is shown in Fig. 18. Curdling cans are ranged on a shelf a few inches above the floor along one side of the room below an open tin trough with side branches. This open trough brings the milk from the mixing vat to the curdling cans. (The open tin trough offers no lodgment for dirt.) The cans hold about 200 pounds of milk, are about 12 inches in diameter at bottom, and 20 to 24 inches at top. They are heavily tinned. Iron trucks as high as the shelf and with tops the same diameter as the bottoms of the cans form a con- venient method of bringing cans of curd to the very edge of the draining tables. The wooden draining tables are placed about 32 inches above the floor; they FIG. 19. — Draining mat for Camembert cheese. are usually made of 2-inch lumber, have raised edges and slope slightly toward the wall. Whey and wash water are thus carried to a draining trough along the wall. For cheese-making, each is covered with a strip of matting consisting of wooden strips held together by thread (Fig. 19). The strip of matting should be exactly the width and length of the table. The hoops used are heavy tin, with edges turned and soldered, about 5 inches high, 4f inches in diameter with three rows of SOFT CHEESES RIPENED BY MOLD 121 holes about A inch in diameter and 2 inches apart in the row. These hoops are placed as thickly as possible upon the mats. 147. Outline of making process. — The making process l is summarized as follows (Thorn, 1909) : Starter. — From 0.5 to 1.0 per cent of active starter is added to milk kept overnight below 60° F. Acidity at renneting. — Milk titrated to phenol- phthalein should test 0.20 to 0.23 per cent calculated as lactic acid. Temperance of renneting. — 84°— 86° F. is used for Camembert. Rennet. — From 3 to 5 oz. of standard rennet extract to 1000 Ib. milk (10-15 c.c. per 100 Ib. milk) produces a curd of proper texture. Curdling time. — To reach the proper condition for handling, 1^ to 1^ hours or longer is required. This is indicated by the onset of " sweating " or the separa- tion of large drops of whey on the surface of the solid curd. Dipping. — A long-handled dipper is used to transfer curd from cans to hoops. This can be lowered into the hoop. This transfer is to be done with the least pos- sible breaking. One dipperful is transferred at a time to each of a series of hoops. By the time the series is covered, some drainage has occurred and a second dip- perful is added to the contents of the hoop. In this way the hoop is filled within a period of two to four hours. Draining. — Hoops when properly filled have taken in approximately 2 quarts of milk each. No pressure 1 Lot record cards for the making and ripening of Camembert are given on pages 124 and 125. 122 THE BOOK OF CHEESE is used. Cheeses drain by gravity. They stand un- turned until the following morning when they should be firm enough to permit turning without removing the hoops. The cheeses when firm enough to handle (usually on the third morning) are salted by dusting the entire surface with coarse salt and permitting all that adheres to remain. The cheeses should then be removed to a room at about 58° F. to prevent too rapid leakage of water and salt from their surfaces. Ripe cheeses of good qual- ity show a total salt-content varying from 2.25 to 3 per cent with an average of about 2.5 per cent. When so handled there is slight, if any, loss of water and salt in the salting period of twenty-four to forty-eight hours. At the end of the salting period such cheeses should carry 55 to 57 per cent water or slightly more. 148. Acidity. — The essential biological factor in the making period of Camembert is proper souring. The milk should be free from gassy organisms. The lactic starter required should introduce the typical lactic organ- ism (Streptococcus lacticus) in numbers sufficient to sup- press all other forms during the next twenty-four hours. The amount of acid starter introduced, however, plus the acid resulting from growth during the curdling period, should not produce a grainy acid curd. The tempera- tures of handling are such as to favor this group of organ- isms if properly introduced and permit the development of nearly 1 per cent of acid (estimated as lactic) by the second morning. Cheeses with such acid are fairly free from further danger from bacterial activity. Members of the high-acid group (B. Bulgaricus and allies) may be found in these cheeses but do not appear to develop in numbers sufficient to affect the cheese to any marked degree. SOFT CHEESES RIPENED BY MOLD 123 149. Ripening the cheese. — The cheese is now ready for the ripening rooms (Fig. 20). For this process tem- peratures between 52° and 58° F. are desirable ; lower FIG. 20. — Halloir, the first ripening room for Camembert in an American factory. 124 THE BOOK OF CHEESE CAMEMBERT CHEESE RECORD Date Set No. Amt. milk No. cheese Milk per cheese... Producer of milk Apparent cleanliness of milk Acidity : Before adding starter „• After adding starter After acidity period Whey at dipping Starter : Kind a...- Age Amt. Color : Amount Curdling : Temperature used Amount of rennet Time at which rennet is added Time at which milk is curdled Time of curdling Quality of curd - Dipping : Cut or uncut Amt. of cutting Draining : Temperature of room during Condition of cheese after. Salting : Time of Total amt. of salt used.. Kind of salt. Amt. of salt per cheese Mold inoculation : Form of culture used Method of inoculation Time of inoculation Remarks on making : Curing : Transfer of curing rooms Condition of cheese Rooms — Dates.... SOFT CHEESES RIPENED BY MOLD 125 Mold growth : Date of first appearance Purity and vigor Date of changing color Surface of slimy growth : Extent of General character of Surface contamination : Mold Oidium Yeast Bacterial. Wrapping : Date Material Condition of cheese Ripening : Rapidity of Texture Flavor : Ripened curd Unripened curd Special treatment and reasons for same : Record of treatment by days Room Date Observations. ID 16 D. 2D . 17 D. 3 D „ 18 D. 4 D 19 D. 5 D 20 D. 6 D 21 D. 7 D 22 D. 8 D ... 23 D. 9 D 24 D. 10 D 25 D. 11 D 26 D. 12 D 27 D. 13 D 28 D. 14 D 29 D. 15 D.... 30 D. 31 D. 126 THE BOOK OF CHEESE temperatures only delay the process; higher temper- atures favor undesirable fermentations. The cheeses rest upon coarse matting (Fr. clayons) consisting of round wooden rods about the size of a pencil separated 1-1-J- inches and held in position by wire strands. As- suming cheeses of optimum composition as indicated above, the relative humidity of the ripening rooms should be 86 to 88 per cent. Higher humidities produce too rapid development of slimy coatings; too low. humidity is indicated by drying, shrinkage and the growth of green molds on the surface. A slight and very slow evapora- tion is demanded ; by this the water-content of the cheeses is reduced 3 to 6 per cent in two weeks. During the first two weeks of ripening, the cheeses commonly show some growth of yeast and Oidium lactis first, followed by cottony white areas of Camembert mold (Penicillium Camemberti). This mold must be introduced by inocu- lation in new factories but once firmly established in the factory will propagate itself if conditions are kept favorable. Climatic conditions in most dairy sections of America have been sufficiently unfavorable to make more or less continuous use of pure cultures desirable. At the end of two weeks, Camembert cheeses should show a well-established rind, consisting of a well-matted felt work of mold hyphse through the outer 2 mm. (^ inch) of the whole surface of the cheese. More or less of the pale gray-green fruit of the characteristic Penicillium Camemberti can usually be seen. Beginning at about twelve to fourteen days,1 a softening of the curd is first 1 Bosworth, A. W., Chemical studies of Camembert cheese, N. Y. (Geneva) Exp. Sta. Tech. Bui. 5, pages 23-39, 1907. Dox, A. W., Proteolytic changes in the ripening of Camembert cheese, U. S. Dept. Agr. Bur. An. Ind. Bui. 109, pages 1-24, 1908. SOFT CHEESES RIPENED BY MOLD 127 directly detectable under the rind. This is preceded by the disappearance of the acidity of the curd, which pro- gresses inward. The softening of the curd follows closely the lowering of the acidity. Thus a litmus test taken along the cut face of a Camembert cheese at any stage of softening will always show a sharp acid reaction in the solid sour portion which changes to alkaline just before the softening due to proteolytic action becomes noticeable. These two changes appear to be due to en- zymes secreted by the mycelium of the Penicillium Cam em- berti and Oidium lactis which constitute the most active factors in the ripening. Some accessory bacterial action is indicated but of minor importance in the changes found. To avoid loss from breaking, after the softening of the curd has fairly begun, the cheeses must be removed from the coarse matting to smooth boards where they are watched and turned repeatedly, or as in the more common practice, wrapped at once in parchment paper and boxed. The ripening may be completed in either way. The conditions necessary are such as to favor the extension of slimy areas of bacteria over part or all of the rind to the exclusion of further development of gray-green fruit- ing areas of mold. Complete softening may occur in three weeks in cheeses in which evaporation has gone on too slowly. Such cheeses are found to contain 51 to 55 per cent of water when ripe and decay very quickly. If handled properly, the water-content should fall from about 57 per cent at the beginning of ripening to 48 per cent at its completion which should require a minimum period of about four weeks. It is more desirable that a cheese four weeks old show a thin core of sour curd in the center than that it be entirely liquid at that age. 128 THE BOOK OF CHEESE 150. Composition. — Properly ripe Camembert shows about the following range of composition : Water 47 to 49 per cent ; fat 25 to 28 per cent ; protein 18 to 21 per cent; salt 2.2 per cent to 2.8 per cent. Variations out- side these limits are usually associated with less desirable qualities. The approximate limits and characters out- lined for Camembert still leave a considerable latitude for variations in practice which characterize the output of particular factories in a producing group. At one FIG. 21. — Very soft Camembert cheese. extreme are brands of Camembert cheese which are very soft (Fig. 21), some of them actually liquid when ripe, and which have very strong odor and taste ; one such brand has held first place in the trade of certain American cities for years. Another popular brand when fully ripe is wrell covered with yellow-orange viscid slime 1 but is 1 Esten, W. M., and C. J. Mason, Bact. Stud, of Camembert cheese, Storrs Exp. Sta. Bui. 83 (1915), pages 103-111. SOFT CHEESES RIPENED BY MOLD 129 fairly firm in texture with high flavor; still others show dry moldy surfaces and mild flavors. The product of certain factories is always characterized by the presence and characteristic ammoniacal odor of Penicillium br&vi- caule. Each of these forms seems to appeal to some classes of consumers, so that in handling imported Camembert the trade comes to assign the product to specific groups of purchasers according to the conditions observed at its arrival from Europe. 151. Factory. — The type of factory to be used in making and ripening Camembert must be adjusted to •wiiwaii. f i II MM FIG. 22. — Camembert cheese factory at Lisieux, France. The square windows are seen in the second-floor rooms. the climate. This product originated in the Normandy section of France which is but a few feet above sea level, is swept by winds from the Gulf Stream, and has a narrow range of temperature, with highly humid conditions. In that region, every effort must be made to secure ventila- 130 THE BOOK OF CHEESE tion to carry off the necessary amount of evaporation water. In contrast, most of the dairy sections of America have land instead of sea breezes, much higher altitudes, much greater extremes of temperature and a lower range of relative humidities. The conditions of an upstairs room full of windows in Normandy (Fig. 22) are most readily reproduced in rooms partly or completely be- low ground in this country. The industry calls for the production and maintenance of a specific set of working conditions. These are furnished by nature in northern France, probably also in certain Pacific coast areas, but must be artificially obtained where the climate is un- favorable. 152. Economic factors. — Camembert cheeses show a yield of about 13 pounds to 100 pounds of milk testing 4 per cent fat. At roughly one-half pound each, the number of cheeses will be approximately twenty-six. Assuming no losses and a wholesale price of 15 cents each, the wholesale value of 100 pounds of milk would be $3.90. The labor cost of production is high, the pack- age represents (box, wrapping and label) at least 1-J cents a cheese. The time between the purchase and the consumption of the cheese will average about one month. Few cheeses actually remain this length of time in the possession of the maker. This short investment period, therefore, is a distinct advantage of Camembert. Among disadvantages, however, the extremely perishable char- acter of the fully ripe cheese makes provision of an ade- quate and constant market essential. Losses due to failures in manufacturing or ripening conditions are also frequent. Excessive heat in summer and very cold periods in winter are both unfavorable. The Camembert- maker cannot, therefore, use the cheapest milk of the SOFT CHEESES RIPENED BY MOLD 131 summer months at all and the losses entailed by failure of control in winter fall on the most costly milk of the year. Camembert requires, therefore, careful selection of the location for manufacture and ripening, effective control of conditions throughout the period and adequate marketing facilities. Camembert at its best is one of the finest of all cheeses ; when bad, it becomes quickly inedible and is a total loss. 153. French Brie.1 — Brie cheese has its center of production in Seine-et-Marne, east of Paris in northern France. The apparatus, arrangement of the factories and details of manipulation differ from those described for Camembert, but the final product is in flavor and texture closely related to Camembert. Brie cheeses are the same thickness as Camembert, 1 to \\ inches ; in diam- eter, however, there are three or more sizes varying from 8 to 16 inches, or even greater. The largest cheeses weigh 5 to 6 pounds. As in Camembert, practices of making and ripening vary to such a degree as to produce various qualities of product. These run from whole milk through all shades of skimming. Perhaps the best established practice puts the cheese -making room next to the "stalls of the cows. The milk is drawn, strained directly into the curdling cans and renneted while still warm, — 86-92° F. (30-33° C.). No lactic starter is added and no ripening period is given to the milk. The other manipulations differ only in detail from Camembert. Ripening of Brie follows the same course with the same organic agents, namely, Camembert mold (Penicillium Camemberti) and Oidium lactis with the accompaniment of a mixture of slimy organisms upon the surface of the 1 See page 134 for domestic or American use of the name Brie. 132 THE BOOK OF CHEESE cheese. The process admits of many minor modifications each capable of affecting the product in a characteristic way. The judgment and skill of the maker is given a wide opportunity to establish and work toward a par- ticular ideal of appearance and texture and flavor. Brands with characteristic qualities, therefore, command their own market. Brie as known in France must not be confused with the American " dTsigny," or with the particular sizes of that type which have been called Brie on account of diameter only. Very little Brie as known in France has been made in America and only a limited amount has been imported for very restricted trade. 154. Coulommiers. — Another member of the Camem- bert group is called, from its place of origin, Coulommiers. This form is made at the same thickness as Camembert and about 5j inches in diameter. It appears as either a ripened or unripe cheese. As a ripened cheese, Coulom- miers is not essentially different from Camembert except that some brands are made without salting. As a cheese eaten unripe, it has certain advantages over the other cheeses with the flavor of sour milk only. The cottage and (American) Neufchatel group of cheeses comprises the best known forms with the acid flavor. These cheeses are very perishable in nature. On the other hand, Coulom- miers as eaten fresh can be held and used over a much longer time without loss. Coulommiers 1 in this sense is simply a fresh Camembert. Such a cheese, when ready for the salting process, is a firm sour mass, close textured, almost impervious to air and but slowly permeable to liquids. Spoilage in such a cheese begins only on the 1 McNaughton, J., Coulommier cheese, Dept. Agr. Ottawa, Canada, Dairy and Cold Storage Ser. Bui. 25, 1910. SOFT CHEESES RIPENED BY MOLD 133 outside, and not throughout the mass as in cottage cheese or Neufchatel. Successive portions of such a cheese can be removed daily over a considerable period with no loss of substance aside from slight scraping at times and little or no change in flavor. This product has very tan- gible merit for manufacture and use on the farm in many sections of America. CHAPTER IX SOFT CHEESES RIPENED BY BACTERIA A BACTERIALLY-RIPENED series of cheeses parallels the mold-ripened group as typified by Camembert. Although the varieties overlap, these may be roughly grouped as : (1) those made from friable or soft curd; (2) those made from firm or rubbery curd. In the first group, the curd is set at 86° F., or below; in the second, the rennet is added at 90° F. or above. In the first, the lower tem- perature and long curdling time with ripened milk gives a soft friable curd which may be toughened somewhat by cutting and stirring in the whey. This section is typified by dTsigny, American Brie, Liederkranz. In the second, curdling of unripened milk at temperatures of 90° F. or above insures a smooth elastic curd which fuses more or less completely into the firm rubbery "mass typified by freshly made Limburger. 155. The Isigny group. — A series of names, dTsigny, Brie, Brie dTsigny, combined with trade names, are used for a domestic cheese, made in a small number of factories distributed over New York, Pennsylvania, Michigan, Illinois, Wisconsin, Iowa and California. The cheeses sold under the separate varietal names differ only in diameter; their thickness is fairly uniform; the process of manufacture and ripening with resultant textures and flavors furnishes no fundamental varietal 134 SOFT CHEESES RIPENED BY BACTERIA 135 characters, although the products of the several factories show noticeable differences in market quality. D'Isigny, while the name of a French town famous for butter production, is not used to designate a cheese in France. It may, therefore, be accepted as a French name arbitrarily applied to a domestic product. Brie as used in France is a markedly different cheese (p. 131), and the name should be dropped from this form as made in America. As used for a member of this series made in America, it merely means cheese 7 to 15 inches in diameter. The cheese partakes of the characters of French Livarot, and of Pont 1'Eveque without exactly reproducing either form. The milk varies from separator skim to whole milk, with resultant differences in quality. Freedom from gas is essential to the best results. The milk is curdled at 85° to 86° F. with sufficient rennet to produce a very firm curd within a period of one and one-half hours. Curd is then cut in two directions, allowed to stand a few minutes or gently agitated to produce a very slight toughness or " worked " condition, then scooped into hoops 4^ to 5 inches in height and varying in diameter from 2j to 15 inches according to the size selected for manufacture. To aid in the escape of whey, three rows of holes -T2 inch in diameter and 2 inches apart in the row are made in each hoop. The hoops are arranged upon draining tables with more or less corrugated surface, which for best drainage should be covered with matting. The cheeses are allowed to drain without pressure. They are commonly turned the second morning, although they are sometimes solid enough to turn within the first day. When fully drained, the cheeses are salted by rubbing coarse salt on the surface, after which they stand an extra day. They are then arranged upon shelves in a 136 THE BOOK OF CHEESE ripening room held between 50° and 60° F. with humidity so high that evaporation is kept at a minimum. In this room, a surface slime develops quickly. This consists of bacteria of several forms, yeasts, Oidium lactis and accidental species of other molds'. During this ripening, the cheeses are turned, rubbed with the hands, washed with salt water and scraped if infected with molds which produce colored colonies. In the course of ripening, the slimy surface layer acquires a yellowish orange color with the strong odor and taste characteristic of the series. Brands of d'Isigny are made from every grade between separator skim and whole milk. They reach the market in' condition all the way from "Kosher" forms1 which are eaten entirely unripe, to brands which approximate the qualities of Limburger and others which approach Port du Salut. The biology and chemistry of the ripening of this type of cheese have not been completely followed. An initial souring process always takes place quickly. Oidium lactis is always present in some degree on the surface, but the organisms in the yellowish to orange slime on the surface of the cheese appear to produce the characteristic odor and taste. These appear to be due to the develop- ment of volatile fatty acids, such as valerianic and ca- proic, which diffuse throughout the cheese, even pene- trating the unripened sour portions. The same odor and taste in varying intensity are present in Limburger, Brick, and a long series of German varieties not handled in America. High-flavored cheeses such as these, form an acceptable part of the meal in cases in which the intensity of other 1 Kosher forms are prepared in compliance with the Mosaic law as demanded by the Jewish trade. SOFT CHEESES RIPENED BY BACTERIA 137 flavors is such as to mask entirely the milder flavors of Camembert or cream cheese. In composition, a characteristic whole-milk brand of this group showed the following analysis : 1 water, 45.5 per cent; fat, 25.28 per cent; protein, 18.22 per cent. 156. Raffine.2 — This cheese is made in the French settlement of the Isle of Orleans in the St. Lawrence River. The practice seems to have been brought from France and represents an intermediate product between Camembert and perhaps Livarot, a cheese on the border- line between Camembert and Isigny as made in America. The outline of the making process as given follows: Milk freshly drawn is curdled without cooling, at approxi- mately 90° F. The rennet is prepared on the farm. About one-half hour is required for curdling. The curd is cut into 2-inch cubes. Whey is removed as fast as it separates. About two hours are required for draining. The curd then goes into the hoops. The metal hoops, which are closed at one end, are 6 inches high, 4| inches in diameter, with holes about rg- inch at intervals of about J inch, and stand upon three legs about 1 inch in height. When filled, the cheeses are left on a draining table. Some salt is put on top while draining. When the volume is reduced to one-half, the cheese is turned. The drain- ing room is kept at about 70° F. After they are firm enough to handle, drainage is completed on racks covered with rush matting. These are arranged on special racks. The cheeses are turned twice a day, and washed in slightly 1 Unpublished analysis of the -Stores Exp. Sta. 2 Chapais, J. C., Monographic, Le Fromage Raffine de L'Isle d'Orleans. Quebec, 1911. Published by Ministry of Agricul- ture, pages 1-31. 138 THE BOOK OF CHEESE salted water every two days. After each washing, they are drained for two hours on cloth, and placed on clean matting. This treatment continues about fifteen days. After fifteen days on the matting, the cheeses are ready for ripening. They are first covered with cold brine and let stand twenty-four hours. The cheeses are packed in rolls or tiers in boxes, covered with cloth and ripened at 45° F. They must be kept moist ; if signs of drying appear, moisture must be added. If the cheeses develop yellow slime, they are washed with clear water and rinsed in water with salt added. After a ripening period of three weeks, the cheeses should begin to be soft when pressed with the finger. The growth of molds must be prevented by washing the boxes, cloths, and washing and scraping the cheeses if necessary. When the cheeses are ready for the market, they are scraped clean and white, wrapped separately in cheese-cloth or parchment paper and packed into the boxes. Ripe cheeses are about 5 inches in diameter, 1 inch thick and weigh a little over 5 ounces. The outline of the Raffine process follows : coagulation by rennet 30 minutes cutting and draining curd .... 2 hours draining in hoops . 10 hours stand on mats 15 days ripening in boxes 21 days Total period 36 days The treatment described closely resembles the handling of Livarot cheese in the department of Calvados, France. 157. Liederkranz cheese. — Among the specialties in the bacterial group is Liederkranz, made from curd with the soft friable texture of a Camembert, molded in rec- SOFT CHEESES RIPENED BY BACTERIA 139 tangular blocks of about 4 ounces in weight and ripened very completely. Although this name is the private brand of a single factory, it has become widely known with the effect of creating a type name in the American market. Analysis of this brand of cheese gives about 55 per cent water, 25 per cent fat, 17 per cent protein, which in- dicates a whole milk cheese. 158. Limburger cheese l derives its name from the town of Limburg in Belgium. The manufacture of this cheese is now widely practiced in Europe and in certain parts of the United States, especially in New York and Wisconsin. Practically no cheese of this name is at present imported, and the practices described are limited to those in American factories. 159. The milk. — Limburger cheese is probably best known on account of its pronounced odor. Because of this characteristic pungent smell, it is often thought that the cheese is made in dirty or unsanitary places. On the contrary, Limburger cheese is usually made in small factories which are clean and sanitary. Because of the constant attention required, a cheese-maker can handle only about 2000-2500 pounds of milk a day, and then some help is necessary to care for the cheeses in the curing room.2 The discussion of the milk given in Chapter II applies to that to be made into Limburger cheese; however, Limburger requires sweeter milk than do some of the other types. To be sure of obtaining very sweet milk, it is the usual practice for the milk to be delivered without cooling morning and evening 1 The authors acknowledge the assistance of Mr. Louis Get- man in preparing this description. 2 Zumkehr, P., Limburger cheesemaking, Wis. Cheese-makers Association, 15th Annual Meeting, 1907, page 62. 140 THE BOOK OF CHEESE at the cheese factory. The cheese is made twice a day. Because the milk must be delivered twice daily, it is obtained from only a few producers near the factory. A factory usually does not have more than eight to twelve patrons. Because of the small number of patrons, it is comparatively easy to obtain a supply of fresh clean milk. The factories are variously built. A common type takes advantage of sloping ground so that the floor at FIG. 23. — A common type of Limburger cheese factory. one end may be on the ground level and run backward into a hillside until the other end is a cellar with small windows at the ceiling opening at the ground level (Fig. 23). The family of the cheese-maker often lives in the same building above the factory. 160. Making the cheese. — Limburger cheese is made from the whole milk. When the milk is received at the factory, it is placed in the cheese vat. As the milk is delivered both morning and evening without cooling, it reaches the factory at a temperature of 90 to 96° F. SOFT CHEESES RIPENED BY BACTERIA 141 In some cases the night's and morning's milk is mixed and then warmed to about 94° F. This practice is not recommended but is frequently adopted, when the supply of milk becomes too small to work in two lots. As soon as all of the milk has .been delivered, the cheese-making process begins. No starter is used. The milk is not ripened because no acid development during the making process is desired. > The milk is set or curdled at the temperature at which it is received at the factory, usually from 90 to 96° F. Sufficient rennet extract is used to give a firm coagulation in twenty to thirty minutes. This usually requires 2j to 3 ounces of rennet extract for each 1000 pounds of milk: This is diluted in about forty times its own volume of cold water and added to the milk. (For method of adding rennet extract to milk, see Chapter V.) When the coagulum has become firm so that it will split clean over the finger, the curd is ready to cut. Coarse Cheddar cheese knives are used. Sometimes only the perpendicular knife is employed, and the curd is broken up while being stirred with the hands and rake. This usually causes a large fat loss. After cutting, the curd is stirred first by hand and later with an ordinary wooden hay rake. Usually the curd is not " cooked " or heated after setting, though occasionally it is brought up as high as 96° F. to 98° F. If the curd does not firm up, the temperature may be raised to 98° to 100° F. to aid in expelling the moisture. When ready to dip, the curd should still be in large soft shiny pieces. It requires from one hour to an hour and thirty minutes from the time the rennet extract is added until the curd is ready to dip. When, in the judgment of the cheese-maker, the curd has become suffi- 142 THE BOOK OF CHEESE ciently firmed in the whey, the whey is drawn down to the surface of the curd. The curd is then dipped into the Limburger molds. These molds are 5 inches square by 8 inches deep without top or bottom. Usually there are five or six of these molds built together into a section. These molds are placed on a draining table beside the vat and the curd is ladled into them with a large tin ladle. The draining table has strips on both sides and one end and slants toward the other end so that the whey will drain from the curd and yet not go on the floor except at the one end. This makes it easy to save and catch the whey for stock feed. 161. Draining and salting Limburger. — In some fac- tories, a clean piece of burlap is put on the draining table and the molds and curd placed on the burlap. This aids in the rapid draining of the whey from the curd and pre- vents the loss of curd particles. The curd should be turned frequently in the mold to obtain uniform draining. The molds are transferred to the salting room as soon as well drained, usually in about twelve hours, but sometimes they are left until the following morning. Here they are placed on another draining table, which has strips about 5 inches high on the sides and one end. The cheeses are placed along this board, each cheese being separated by a piece of board 4 inches high and 5 inches wide. When the row is filled, a long strip the length of the table is placed against the row. Another row is laid down against this strip in the same manner as the first, and so on until several rows are on the table. The last long strip is held firmly in place by sticks wedged between it and the opposite side of the table. These strips and pieces form a mold for each cheese while draining. Usually the cheeses are turned several times SOFT CHEESES RIPENED BY BACTERIA 143 in this period to obtain a uniform expulsion of whey. In about twenty-four hours the cheeses are ready to be salted. This is done by applying the salt to the outside of the cheese. The edges are rolled in a box of salt and the salt then rubbed on the two broad surfaces. Any excess salt is brushed from the cheese with the hand. The cheeses are then laid on a draining table in single layers. The second day, they are salted again in the same way and piled two deep ; they are salted again the third day and piled three or four layers deep. The salting room or cellar should have a temperature of 60° F. and be fairly damp. The amount of salt used is very important. The tendency is to use too much salt. This retards the ripening process and in extreme cases gives the cheese a salty taste. If not enough salt is used, the cheese will deteriorate very rapidly on ac- count of the development of undesirable types of fer- mentation. The cheeses when salted are then placed in the curing room, which is a cellar, usually beyond the salting room. This cellar should have a temperature of 58° to 64° F. and a relative humidity of 95 per cent of saturation. In winter it is necessary to have a fire to keep the rooms warm, otherwise the cheese would cure very slowly or not at all. In some factories the curing and salting cellars are a single room. 162. Ripening Limburger. — When first placed in the curing cellar, the cheeses are put on edge close together, and as they cure are gradually separated. While in the curing cellar, the cheese must be rubbed frequently by hand and washed, usually with salt water. The object of the rubbing is to keep the surface of the cheese moist and prevent the growth of molds. The drier the cheese and the more mold, the oftener the cheeses must be 144 THE BOOK OF CHEESE rubbed. The drying or the evaporation from the cheese can be retarded by sprinkling the floor of the cellar with water. When first placed in the curing cellar, they are usually rubbed daily; after a few days they are rubbed every other day and finally as often as the cheese-maker can find time to work at them. The more the cheeses are rubbed, the better the rind. In the curing of Limburger cheese, protein compounds are attacked by the micro-organisms. Certain highly- flavored fatty acids are commonly produced.1 This change works most rapidly near the outside and more slowly toward the center of the cheese. The stage of ripening can be determined by examining the cheese. When first made, a cheese is harsh and hard and the outside is more or less white : as the curing changes take place, the cheese becomes soft and pasty or buttery. The outside color changes from a whitish to a yellowish and finally even a reddish brown. It requires consider- able time for the ripening agents to work from the outside to the center of the cheese. As ripening progresses, Limburger cheeses tend to become soft enough to break in handling. If such cheeses are wrapped in manila paper after three to four weeks of ripening and packed in boxes, losses from handling are eliminated. One loose board is left on each box and the boxes remain in the ripening cellar until the cheese-maker decides by removal and examination of cheeses from time to time that they are ready for shipment. When fully ripe, the cheese spoils very quickly. Unless handled very carefully, the outer part may actually rot before the interior is fully ripe. The cheeses are shipped from the 1 Currie, J. N., Flavor of Roquefort cheese, Jour. Agr. Re- search 2 (1914), no. 1, pages 1-14. SOFT CHEESES RIPENED BY BACTERIA 145 factory when they are eight to ten weeks old. They are then placed in cold storage, which checks the action of the ripening agents and so lengthens the commercial life of the cheese. 163. Marketing and qualities of Limburger. — • As shipped from the factory, each cheese is wrapped in heavy manila paper and frequently also in tin -foil. The cheeses are packed in boxes which hold forty-eight. Each cheese weighs about two pounds. Limburger cheese should be regular in shape. The rind should not be cracked or broken nor the sides bulged, nor should it be lopsided. It should have the pronounced characteristic flavor, without other objectionable flavors due to undesirable fermentations. The body should be uniform throughout. It is common to find cheeses that have not a uniform body, due to lack of curing ; a small part of the interior at the center will be hard and not cured, while the remainder of the cheese will be soft and buttery. The color should be uniform. When not en- tirely cured, the uncured part at the center is usually of a lighter color. The cheese should contain the proper amount of salt. The most common defect is in the flavor. If the milk is not free from bad odors and flavors, these are apt to be more pronounced in the cheese than in the milk. .(For care of milk see Chapter II.) Gas-forming fer- mentations are very bad in this variety of cheese as they cannot be controlled and give the cheese a bad flavor and a " gassy body." When a cheese is gassy, the sides are most liable to be bulged and the body is full of gas holes or pockets. Another defect is a sour cheese. This is caused by the development of too much acid in the milk or during the manufacturing process. A sour 146 THE BOOK OF CHEESE cheese usually cures slowly and has a pronounced sour taste. The body is hard and bitter. If the cheese contains too much moisture, it will cure rapidly and the body will be very soft and pasty. In extreme cases it will be so soft that it will run when the rind is broken. On the other hand if the cheese does not contain sufficient moisture, it will cure very slowly and the body will be hard and dry and sometimes crumbly. There is no standard score-card for judging Limburger cheese. The Wisconsin Cheese-makers Association l uses the following score -card for Limburger : Flavor 40 Texture 40 Color 10 Salt 5 Style __5 . Total 100 164. Yield and composition of Limburger. — The yield of cheese depends on : (1) the amount of fat and other solids in the milk from which it is made ; (2) the amount of moisture incorporated into cheese; (3) the loss of solids during the manufacturing process. The yield varies from 12 to 14 pounds of cheese from 100 pounds of milk. The more fat and other solids in the milk, the more cheese can be made from 100 pounds- of the milk. The more moisture incorporated into the cheese, the larger the yield. The quality of the cheese and the amount of solids determine the amount of mois- ture that can be incorporated into the cheese. The greater the losses during the manufacturing process, the 1 Wis. Cheese-makers Assoc., 12th Annual Meeting and Report, 1906, page xxviii. SOFT CHEESES RIPENED BY BACTERIA 147 less is the yield. The composition of Limburger cheese is affected by the same factors as the yield. The average cheese probably carries from 40 to 42 per cent of moisture. Limburger cheeses will vary in composition from this analysis about as follows : water 38 to 44 per cent, protein 21 to 25 per cent, fat 25 to 30 per cent. The differences in practice in factory groups are considerable. Certain markets call for more solid brands, others for the very soft forms. 165. Munster cheese originated in Germany near the city whose name it bears. There is a limited de- mand for this variety in America; therefore it is not extensively made. It is usually manufactured from whole milk in a Limburger or Brick cheese factory. The process of manufacture is between that of these two varieties in temperatures used, firmness of curd and amount of moisture in the curd and cheese. The process is prob- ably more like that of Limburger. The curd is firmed more in the whey than for Limburger, and more acid is developed. The cheeses are pressed or drained in round forms 7 inches in diameter and 6 inches high. The hoops are lined with cloth to prevent the loss of curd particles while draining. When the cheeses are sufficiently drained, until they are firm enough to hold their shape, the cloths are removed. The cheese is salted by rubbing dry salt on the surface or soaking the cheese in brine. The prod- uct is handled in the curing room very much the same as Limburger or Brick cheese. When sufficiently ripe, each cheese is wrapped in parchment paper and placed in a separate wooden box. This cheese, when cured, has a characteristic flavor which is between that of Limburger and Brick. The body is more or less open. The essential factor in the manufacture of Munster cheese is clean 148 THE BOOK OF CHEESE milk. Bad fermentations, such as produce gas and bad flavors, seriously interfere with the manufacture and sale of the product. The cheese is usually made in the late fall and winter, when it is difficult to manufacture Limburger. CHAPTER X SEMI-HARD CHEESES BETWEEN the quickly perishable soft cheeses and the typical hard group, are two series of varieties, one ripened by green mold and best known by Roquefort, the other ripened by bacteria and typified by Brick cheese. These cheeses are fairly firm, hold their shape well, ripen over a period varying from a few weeks to several months and their marketable period is com- paratively long. In texture they are intermediate be- tween the conditions known as " soft " and " hard." In water-content, they range at their best from 37 to 45 per cent. Outside these limits, the cheeses are often marketable but they lose in quality l and trueness to type. 166. The green mold group. — There are three well- known semi-hard cheeses ripened by green or blue-green mold.2 The mold is an incidental factor in certain other forms but none of these forms has won larger than local or purely national recognition. French Roquefort, on the contrary, is probably the most widely known of all cheeses. Stilton, to a small degree at least, has followed the English to the many lands they inhabit. Gorgonzola, although 1 Currie, J. N., The relation of composition to quality in cheese, American Food Jour. 11 (1916), no. 9, page 458. See also Dox on the True Composition of Roquefort Cheese, Ztsch. Untersuch. Nahr. u. Genussmtl. 22 (1911), pages 239-242. 2 Thorn, C., and Matheson, K. J., Biology of Roquefort cheese, Storrs Exp. Sta. Bui. 79, pages 335-347, 1914. 149 150 THE BOOK OF CHEESE made in Italy alone, has a large market in other parts of Europe and in America. In the manipulations of manu- facture, these forms are not closely related but they re- semble each other in that each becomes streaked or marbled by the growth of green mold (Penicillium Roque- forti) through open spaces within the cheese. The " blue-veined " or marbled cheeses have a characteristic taste which is developed in its most typical form in Roquefort. 167. Roquefort cheese. — This is a rennet cheese made from sheep's milk (with occasional and minor admixture of goat's and cow's milk) in the section of southern France centering about Roquefort in Aveyron. The practices are standardized and controlled by a few companies, thus reaching exceptional uniformity. Roque- fort is uncolored, open, made from firm but brittle or crumbly, not tough or waxy curd. Each cheese is about 7J inches (20 cm.) in diameter and 3J inches (9 cm.) in thickness without a definite rind, and when ripe enough for market is scraped carefully, closely covered with tin-foil and kept in refrigerators. The cut cheese shows extensive open spaces which are lined with green mold. This cheese, in addition to a strong cheesy odor and taste, has a peppery or burning quality which according to Currie 1 is due to the formation of volatile fatty acids such as caproic, caprylic and capric from the butter -fat of the sheep's milk used. A series for Roquefort cheeses selected for excellent quality was found by Dox 2 to show the following composition : 1 Currie, J. N., Flavor of Roquefort cheese, Jour. Agr. Re- search, 2 (1914), 1, pages 1-14, Washington. 2 Dox, A. W., Die Zusammensetzung des echten Roquefort- Kases, in Ztschr. Untersuch. Nahr. u. Genussmtl. Bd. 22, Heft. 4, pages 239-242, 1911. SEMI-HARD CHEESES 151 TABLE IV COMPOSITION OF ROQUEFORT CHEESE WATER PER CENT FAT PER CENT PROTEIN PER CENT ASH PER CENT SALT PER CENT Average .... Minimum . . . 38.69 37.49 32.31 31.50 21.39 19.14 6.14 5.18 4.14 3.64 Maximum . . . 40.10 33.53 23.06 6.81 4.88 The composition of the sheep's milk of the Roquefort producing region is reported by Marre : 1 TABLE V COMPOSITION OF SHEEP'S MILK WATER PER CENT CASEIN PER CENT FAT PER CENT LACTOSE PER CENT ASH PER CENT Range .... Average .... 76-83 79.5 5-8 6.5 5.5-10.5 8.0 4 to 5 4.5 0.8-1.2 1.0 The cheeses when properly made in the local factories are transported to Roquefort for ripening in the famous caves which have made possible the development of a great industry. The Roquefort caves were originally natural openings leading back into the face of a cliff until they reached a deep, narrow fault or crack in the rock leading to the plains above. The cooler air from the plains came down this crack over moist and dripping rocks and issued through these clefts in a cold moisture-laden current which kept the caves about 50 to 55° F. and moist enough to ripen the cheeses without shrinkage. As the business 1 Marre, E., Le Roquefort, Rodez, 1906. This is the authorita- tive monograph on Roquefort cheese problems. 152 THE BOOK OF CHEESE outgrew the natural caves, great cellars, some of them five or six floors deep, were excavated and tunnels were dug back to the crack so that the strong ventilating current reaches every part of the cellars and keeps both temperature and relative humidity favorable to the ripening of the cheeses. 168. Cow's milk or Facons Roquefort. — The supply of Roquefort is automatically limited by the supply of sheep's milk. The sheep gives milk only about five months in the year and at best a scant average of about a pint a day to a sheep. Sheep's milk for cheese-making is not produced, therefore, outside of very limited regions. Some cow's and goat's milk unavoidably finds its way regularly into the industry itself. Attempts were nat- urally made to substitute cow's milk. Outside the con- trolled area, factories were established for this purpose. The quality of the product did not equal that of the Roquefort factories, and French courts decreed that the name Roquefort should not be used for such products. Although some local success was obtained, not much prog- ress was made against the intrenched Roquefort industry. Similar attempts to make such a product in Germany 1 were tried on an extensive scale but failed. More re- cently, under the inspiration of Conn, the United States Department of Agriculture and the Storrs Experiment Station have studied the possibilities of such an industry. Although the work is not completed, the preliminary reports 2 have indicated the fundamental principles which must underlie such development. 1 Reported on the word of Prof. Fleischmann. 2 Thorn, C., J. N. Currie and K. J. Matheson, Studies relating to the Roquefort and Camembert types of cheese, Storrs Exp. Sta. Bui. 79, pages 335-394, 1914. SEMI-HARD CHEESES ' 153 169. Outline of making Roquefort. — Some of the results of these experiments are summarized in the fol- lowing paragraphs : Milk. — Clean-flavored fresh milk testing 4-4.2 per cent fat and up to 2.8 percent casein gives the best results. The milk with a high percentage of cheese-making solids forms a firmer curd, hence works up better in the process than milk of lower quality. Acidity. — The milk is ripened by lactic starter up to an acidity of 0.23 per cent titrated as lactic acid at the time rennet is added. This gives a firm curd, which drains to the desired water-content but is low enough to prevent the toughening effect of too high acid. A very slight increase in initial acid — 1 to 2 hundredths per cent — combined with the rate at which acidity is developing introduces such physical changes in texture as to make the final texture of Roquefort impossible. Temperature. — Rennet is added at or below 84° F. Every degree of heat adds definitely to the efficiency of rennet. Below 82° F., curdling becomes slower and the coagulum softer and more difficult to drain. The sheep's milk curd is made from 76° to 84° F. but sheep's milk has about twice the cheese solids found in cow's milk. It was found necessary to raise the temperature as high as texture would permit. However, at 86° F. the physical character of the curd tends to become tough or waxy in handling. At 84° F. the curd remains brittle and crumbly. It was, therefore, necessary to keep the cur- dling temperature down to 84° F. Renneting or setting. — Rennet at a rate of 3 to 4 ounces of standard liquid rennet to 1000 pounds (10 to 12 c.c. to 100 pounds) was found to give the best curd under experimental conditions. 154 ' THE BOOK OF CHEESE Curdling time. — One and one-half to two hours gave most satisfactory results in forming curd. This should be very firm and stand until it begins to " sweat/' until beads of whey have begun to collect upon its surface. Cutting. — The cow's milk curd gave best results when cut in two directions with the half-inch curd knife. The resulting columns, a half inch square in cross-section, may be handled without excessive losses. Draining. — The cut curd is dipped to a draining rack covered with cloth with as little breaking as possible. During the draining process, a certain amount of turning is necessary to facilitate the separation and escape of the whey. If handled too much, losses of fat are in- creased and the curd becomes tough or waxy instead of remaining brittle or crumbly. When properly handled, not over 0.35 per cent of fat is lost. Under favorable conditions, four-ninths to two-thirds of the original weight of curd will separate and run off as whey in twenty to thirty minutes. The curd meanwhile is exposed to the air of the room and cools toward room temperature. If cooling goes too far, further drainage is interfered with. Hence the curd is put into the hoop and the drainage completed while the cheese is reaching its final form. Hoop. — Hoops for cow's milk Roquefort must be 7 J inches in diameter and about 5f inches high to hold curd enough to produce a cheese the size of the standard Roquefort when completely drained. Sheep's milk with its higher percentage of solids does not require such high hoops. The curd as it goes into the hoop should be a soft, pulpy mass with no suggestion of toughness. Inoculation with mold. — The mold for Roquefort cheese (Penicillium Roqueforti 1) is readily grown in pure 1 Thorn, C., U. S. Dept. Agr. Bur. An. Ind. Bui. 82, 1905. SEMI- HARD CHEESES 155 culture in ordinary loaves of bread. For this purpose loaves hot from the oven are quickly drenched with or immersed in hot paraffine to form an impervious crust to retain moisture as well as to keep out contaminations. It is then allowed to cool. The interior of each loaf is inoculated by drawing a suspension of P. Roqueforti spores in water into a sterile pipette (10 c.c.) which is then thrust through the paraffined crust to the center of the loaf of bread and allowed to empty there. The hole is sealed up with paraffine. These loaves are incubated for about a month at room temperature. When cut, every open space should be found lined with the green spores of the mold. When dry enough, the mass may be powdered, and put into an ordinary pepper box. When the curd is ready to go into the hoop, this mold powder is sprinkled upon it from the pepper box. Handling. — Freshly made cheeses are turned within the first hour to insure the proper smoothness of both sides. Further draining is best accomplished in a room at about 64° F. with a relative humidity of 85 to 90 per cent. If the surface of the cheese becomes too dry, a rind is formed. No real rind is permitted on Roquefort. If the temperature is too high, slime forms quickly and unfavorable fermentation may occur. Slime (bacteria and Oidium lactis usually) must be scraped when it becomes too heavy. Salting. 1 — Experimental cheeses were found to give the best results when at the end of about three days' drainage they contained about 50 per cent water. Such cheeses were salted by sprinkling the entire surface lightly, replaced upon the drain boards for one day, 1 Thorn, C., The salt factor in the mold ripened cheeses, Storrs Exp. Sta. Bui. 79, pages 387-394, 1914. 156 THE BOOK' OF CHEESE salted again and piled in two's. After another day they received the third salting and were piled in three's for two days longer. A total of about 10 per cent by weight of salt was used to secure an absorption of 4 per cent. At the same time the water-content dropped to 40 to 43 per cent. After salting is completed, the cheeses are brushed and punched with holes to permit oxygen to enter.1 They are then ready for ripening. 170. Ripening of Roquefort. — The ripening of ex- perimental Roquefort has required four to six months at a relative humidity of 85 to 90 per cent. This relative humidity is just below the equilibrium relative humidity of the cheese, hence permits a shrinkage of 2 to 4 per cent in the water-content of the cheese. This makes it possible to control the amount of surface slime developed. If the relative humidity goes too high, the surface slime of bacteria and yeasts becomes very heavy, soft and almost liquid, and follows the openings into the cheese with resultant damage to appearance and flavor. Even under the conditions at Roquefort, this slime must be removed by rubbing or scraping several times to avoid injury to the cheeses, together with the production of bad odor and taste. If the humidity becomes too low, the surface becomes dry, hard and cracks open, the friable crumbly texture is injured, and there is consider- able loss in weight. Salt forms about 4 per cent of the cheese. This is in solution in the water present, which is about 40 per cent, and makes a brine of about 10 per cent strength. This strength of brine does not prevent the growth of the Roquefort mold (Penicillium Roqueforti) but does hinder the development of Oidium lactis in the 1 Thorn, C., and Currie, J. N., The dominance of Roquefort mold in cheese, Jour. Biol. Chem. 15 (1913), no. 2, pages 247-258. SEMI-HARD CHEESES 157 open spaces within the cheese. Accurate adjustment of temperature and relative humidity in the ripening rooms to salt and water-content in the cheese is essential to proper ripening. These conditions are furnished by the unique natural conditions of the caves of Roquefort. The production of such cheeses elsewhere depends either on the discovery of another locality with closely similar conditions or on the artificial production and control of the necessary temperature and relative humidity. This has been done on an experimental basis by the use of cold storage apparatus combined with proper humidifiers. The differences between working with sheep's and with cow's milk lie in the making process rather than in the ripening. Sheep's milk freshly drawn shows a higher acidity than cow's milk, probably on account of the acid reaction of its greater casein content. With nearly double the total solids of cow's milk, the yield to one hundred pounds is much greater, consequently the drain- age of the curd is much more easily handled. Once made and salted, the cheeses require very nearly the same conditions of ripening. The resultant products are alike in appearance and texture. In flavor, cow's milk Roquefort differs in character from sheep's milk cheese to such a degree as to be recognized by taste. The difference was found by Currie l to be due to an actual difference in the combination of fatty acids present. Although these differences in character are recognizable by the expert in testing the cheese, as well as by chemical analysis, cow's milk Roquefort would satisfy that large proportion of consumers who use such cheese only in connection with other fairly high flavored foods. The 1 Currie, J. N., The composition of Roquefort cheese fat, Jour. Agr. Research, 2 (1914), 6, pages 429-434. 158 THE BOOK OF CHEESE demands for technical skill and factory equipment are not naturally greater than for many other lines of cheese- making. The gradual development of a cow's milk Roquefort may be anticipated. 171. Gorgonzola * is a rennet cheese made from fresh whole cow's milk, in northern Italy. It takes its name from the village of Gorgonzola, a few miles from Milan, but the manufacture of the cheese has spread FIG. 24. — Gorgonzola ripening establishment in valley near Lecco. over a wide area. The cheeses are made on farms and in factories from which they are transported for ripening to cool valleys of the Alps, principally near Lecco (Fig. 24). Boeggild introduced the making of a cheese after the Gorgonzola process into Denmark about 1885. This industry has been successful on a small scale since that time. Gorgonzola cheeses are about 30 cm. (12 inches) in diameter and 18 cm. (7 inches) thick and weigh 15 to 20 pounds. As exported they are usually heavily 1 Thorn, C., Soft cheese studies in Europe, U. S. Dept. Agr. Bur. An. Ind. Kept. 22, pages 79-109, 1905. SEMI-HARD CHEESES 159 coated l with a mixture usually barite, tallow and lard colored with annatto or other cheese color. This coating prevents shrinkage or mold on the surface of the cheese in transit. When cut these cheeses vary greatly. All show marbling with mold (Roquefort mold). During their ripening they become very slimy at the surface. To open up air spaces for mold growth, this slime is scraped off and holes are punched into the cheeses. These holes are readily seen in the final product. Some show crumbly texture, well distributed mold, as in Roquefort, with flavor approaching that cheese; in others .the texture is waxy rather than crumbly, a condition correlated regularly with different character in the flavor. Fre- quently in whole areas or in small pockets, slime consist- ing of bacteria and Oidium has followed the openings into the cheese and affects its odor and taste. Experimental Gorgonzola cheeses comparable with the Italian product were made with cow's milk ripened as for Roquefort or higher, to 0.25-0.30 per cent (titrated as lactic acid), curdled at 86° F. (30° C.), cut into cubes and slightly stirred, then dipped to a draining board for about one-half hour, and put into the hoop. The cheeses drained quickly to about 50 per cent water and developed a surface rind as in the harder cheeses. Cut surfaces showed a fairly open cheese in which mold grew readily. These cheeses were salted to taste, not to a specified percentage. They ripened with the same irregular results and the characteristic range of flavors found in Gorgonzola. To avoid the rotting of the cheese by sur- 1 Frestadius, A., Nord. Mejeri Tid. 17 (1912), 14, page 159, Abs. N. Y. Produce Rev. 34 (1912), 2, page 54, and Cutting, W. B., The use of baritine in cheese rinds, Mo. Commerce and Trade Repts. 1908, 337, page 144, also in Practical Dairyman, 2 (1908), 7, page 76. 160 THE BOOK OF CHEESE face growths, they were exposed to low humidities for a time and cracks opened at the surfaces, as seen in the ripening rooms at Lecco (Fig. 24). The texture was more or less waxy or tough, which was correlated with the slightly higher heat at renneting together with the stirring or " working " of the curd. Comparative an- alyses of a series of imported cheeses confirm the inter- pretation that the salt-content of Roquefort, 4 per cent FIG. 25. — Gorgonzola cheese curing-room. approximately, prevents the invasion of the interior of the cheese by Oidium. No complete study of the ripen- ing of Gorgonzola -has been made. As far as followed, it consists in an initial souring process followed by ripen- ing by molds and slime organisms. At its best, Gorgon- zola is nearly equal to Roquefort but the percentage of SEMI-HARD CHEESES 161 such quality is low. In spite of its irregular quality, England has used larger amounts of Gorgonzola than of Roquefort. Considerable quantities have been imported for the Italian trade in the United States. 172. Stilton cheese bears the name of an English village 1 in which it was first sold. It is made from cow's milk and is typically a whole milk cheese, although part skim cheeses are regularly made and sold as lower grades. In the Stilton-making counties, the milk from Shorthorn cattle testing about 3.5 to 4.0 per cent fat is preferred to richer or poorer grades. Such milk is curdled with rennet at about 86° F. in about one hour; the curd is cut, dipped to a draining table covered with cloth and drained slowly over a period of several hours, commonly overnight. During this period considerable acidity is developed. The curd is then milled or broken by hand, salted, packed into hoops 15 to 16 inches high and 7 inches in diameter. These hoops are made from heavy tin (Fig. 26) with four rows of holes about T$ inch in diameter. The freshly filled hoops are allowed to stand and drain without pressure in a room at about 70° F. (Fig. 26). Such cheeses are turned every day for several days. When solid enough to stand the hoops are removed, the cheeses are scraped or rubbed with a knife until the surface is smooth, and commonly wrapped with a cloth bandage to maintain the shape, if the cheese is still too soft to stand firmly. In the factories, several rooms are used with varying temperature and relative humidities, which makes it possible to place each 1 Stilton Cheese — J. P. Sheldon — from abs. by New York Produce Rev. 28 (June 16, 1909), no. 8, pages 362-363. Stilton is said to have originated with Mrs. Paulet, Wymondham, Co. of Leicester, and to have been sold by her brother — Host of the "Bill" at Stilton from which village it derived its name. 162 THE BOOK OF CHEESE cheese under the condition best suited to its texture and condition of ripeness. In general, the dairy sections of England are much more humid than those of America and there are less violent changes in temperature. Stilton FIG. 26. — Stilton cheeses in hoops, draining. cheese-making has grown up to take advantage of this climatic factor in handling the product. Transplanta- tion of such an industry necessitates a mastery not only of the manipulations but a grasp of the fundamental principles underlying the process and a readjustment of practices to preserve those principles. SEMI-HARD CHEESES 163 Stilton is, then, a soured curd cheese in whose ripening a very prominent part is played by the green mold (usu- ally some strain of P. Roqueforti) which grows throughout the cavities of its mass.1 At its best, it has attractive texture and flavor. Much of it fails to reach high quality on account of the invasion of bacteria, Oidium lactis,eind very frequently myriads of cheese mites. The following analysis was furnished as typical for ripe cheese by Miles Benson,2 late professor of dairying at Reading, England : Water 31 per cent, fat 36 per cent, casein 29 per cent, mineral constituents including salt about 4 per cent. Approximately the same figures are given by Primrose McConnell (Agricultural Note Book). The low percentage of salt is another factor of uncertainty in the control of this Stilton product, as in Gorgon- zola, since these cheeses are commonly high in water- content at first and are thus subject to invasion by Oidium. Stilton has been made on a small scale in Canada 3 and occasionally attempted in the United States. No serious effort to develop an industry of commercial im- portance has been made in America. Comparative study of the cheeses ripened by green mold tends to the con- viction that the adaptation of the Roquefort practice to the use of cow's milk offers a more satisfactory basis for experiment than efforts to establish a Stilton or a Gorgon- zola industry. 1 Percival, J., and G. Heather Mason, The microflora of Stil- ton cheese, Jour. Agr. Sci. 5 (1913), part 2, pages 222-229. See also Thorn, C., Soft cheese studies in Europe, U. S. Dept. Agr. Bur. An. Ind. Kept. 22 (1905), pages 79-109. 2 Benson, Miles, in personal letter from analyses of cheeses selected for the purpose. 3 Dean, H. H., The Creamery Journal, Nov. 1904. 164 THE BOOK OF CHEESE 173. Gex. — A cheese under this name made in southern France resembles, in its general character as a ripened cheese, the English Stilton and Italian Gorgonzola. Al- though it has no commercial importance, reference is made to this cheese to show that mold-ripened cheeses have been developed entirely independently in different countries to bring about the same general character of product. 174. Bacterially ripened series. — The semi-hard cheeses ripened by bacteria stand half-way between true Lim- burger and the hard forms. In fact, brands of Lim- burger are readily found which approach the texture and ripening of Brick cheese. In the same way, Brick cheeses are often found which have the appearance, texture and much of the flavor of the Cheddars with only a trace of the taste of Limburger. Port du Salut, Oka, Munster, in France Livarot, in the Balkan regions Kascoval, belong in this series. 175. Brick cheese. — The name of this cheese is probably due to the finished product being about the size and shape of a brick. It is similar to the German cheese Backstein and may have been developed from it. It is typically a sweet-curd cheese, made from milk freshly drawn, without permitting the development of appre- ciable quantities of acidity until after the curd has been put into the hoop. In the making process-, it is inter- mediate between Limburger and the cheeses of the Cheddar group. Some cheese-makers use an ordinary cheese vat, others a copper kettle in manufacturing. It is the usual practice to deliver the milk to the cheese factory both morning and evening, without cooling. Cheese is made twice a day. In some cases the milk is delivered only once a day, and extra precautions must then be taken to care for the milk properly. SEMI-HARD CHEESES 165 The discussion of the care of milk in Chapter II applies to that for Brick cheese. For the best quality of cheese, the milk in the vat should show about 0.15 of 1 per cent acidity and never above 0.18 of 1 per cent.1 176. Making of Brick cheese.2 — The milk is received at the cheese factory at a temperature of about 92° to 96° F. For the best results, the acidity should be deter- mined (by the acid test) to decide on the amount of starter to use. Few Brick cheese-makers use an acid test or a starter but these precautions would improve the product of many factories. For method of using the acid test, see Chapter V. Chapter IV discusses the prepa- ration and use of starter. Usually 0.25 to 0.50 of 1 per cent of starter is the amount required. A small amount of starter is used to aid the development of lactic acid and for the beneficial effect 'it has on the flavor. A very small development of acid is desired after adding the starter; therefore the change in acidity should be very carefully watched with the acid test. The vat is usually set when the acid test shows 0.16 of 1 per cent acidity. The more acid in the milk, the less starter should be employed. Sufficient rennet extract should be used to give a coagulation suitable for cutting in thirty to thirty-five minutes. For method of adding the rennet extract, see Chapter V. When the coagulum is firm 1 N. Y. Produce Rev. etc., Vol. 32, no. 14, page 536. 2 N. Y. Produce Rev. etc., Vol. 30, no. 5, page 188; Vol. 30, no. 14, page 534 ; Vol. 31, no. 5, page 182. Marty, G., Brick cheesemaking, Wis. Cheese-makers Assoc., 15th Annual Meeting, 1907, page 66. Wuethrich, F., The manufacture of Brick cheese, Wis. Cheese- makers Assoc., 14th Annual Meeting, 1906, page 50. Schenk, C., Brick cheesemaking, Wis. Cheese-makers Assoc., 13th Annual Meeting, 1905, page 38. 166 THE BOOK OF CHEESE enough for the curd to break clean over the finger, it is ready to cut. The curd is cut with coarse knives into I- or i-inch cubes. After cutting, the curd is let stand three to five minutes, then stirred with the hands for a few minutes until the whey begins to separate and then stirred with the rake. Some makers do not stir by hand but use the rake directly after cutting. When this is done, great care must be exercised to stir the curd with- out breaking up the pieces, because this causes a loss of fat. After cutting the curd is stirred for twenty to thirty minutes before the steam is turned on. The curd is heated very slowly at first and more rapidly during the last stages of cooking. The curd is cooked to a tempera- ture of 110° to 115° F. The lower the temperature that can be used to produce firm curd, the better the texture of the cheese. After cutting and during the cooking, the curd must be constantly stirred so that lumps will not form. When the curd forms lumps, the moisture is not evenly expelled. This results in uneven texture and curing. Sometimes some salt is added to the curd in the vat to restrain souring. The curd is stirred after cooking until it is sufficiently firm. It remains usually in the whey for a total period of one and one-fourth to one and one-half hours from the time of cutting. It is then dipped into forms 10 inches long by 5 inches wide by 8 inches deep. The forms are without top or bottom and are placed on a draining table. This table is so constructed that the whey can be saved for stock feed. When ready to " dip," the whey is drawn down to the surface of the curd in the vat, then the curd is dipped into the forms or hoops. Care must be taken to get the same amount of curd into each form to produce the cheeses of uniform size. Each cheese is turned several times SEMI-HARD CHEESES 167 to insure even draining and even reduction of the temper- ature. While draining, a follower is placed in each hoop and a weight placed on each cheese. Usually a brick is used for this weight. A cheese is allowed to drain or press for ten to fifteen hours. It is then placed on the salting table and rubbed with coarse salt. While on the salting table, a cheese is placed on its broad side. Some cheese-makers prefer to salt their cheeses by soaking them in a salt brine. This brine should be strong enough to float an egg. Salting requires three days. The cheeses are then brushed free from excess salt and taken to the cellar to cure or ripen. 177. Ripening Brick cheese. — For this process, the cellars are kept at about 90 per cent relative humidity and a temperature of 60° to 65° F. Some prefer a tempera- ture for curing as high as 68° F. During the curing, the surfaces of the cheese are kept moist and mold growths- kept down by rubbing or brushing the cheese with pure water or salt and water. In the curing cellars the cheeses are placed on shelves ; at first they are set close together and as they cure, they are separated. During curing, the color changes from a whitish to a reddish brown. The cheese cures from the outside toward the center. When first made, the product is harsh and hard in texture but during the ripening process it becomes mellow and smooth. The cheeses remain on the curing shelves for four to six weeks, after which they are wrapped in heavy waxed paper and boxed. A cheese ready for market usually weighs about five pounds. A Brick cheese box is 5 inches deep by 20 inches wide by 3 feet long, and holds 110 to 115 pounds of cheese. 178. Qualities of Brick cheese. — The cheeses should be neat and attractive and the rind not cracked or broken. 168 THE BOOK OF CHEESE The sides should be square and not bulged. The cheese should have a clean, characteristic Brick cheese flavor. The body and texture should be mellow and smooth and when rubbed between the thumb and forefinger, should break down like cold butter. The color should be uni- form. The cheese should contain the proper amount of salt and moisture. One of the worst faults with Brick cheese is bad flavor. This is many times due to the cheese-maker not using clean flavored starter. It may also be due to bad flavored milk. A Brick cheese-maker has no means of controlling gassy fermentations. These show themselves in the bad flavor of the cheese and in the porous body. They also cause the cheese to bulge. If detected, gassy milk should be rejected. If too much acid is developed, a sour cheese is the result. This will not cure normally and usually has a sour flavor. The body will be brittle and mealy. If too much salt is used, the cheese njay have a salty taste and it will cure very slowly. If not enough salt is used, the cheese may cure too rapidly and undesirable flavors and fermentations develop. The cheese must have the proper moisture- content; if too much moisture is present, the cheese cures too fast and is soft and pasty in body ; if not enough moisture, then the reverse is true. Tabulation of cheeses of special quality, as submitted in scoring contests, show an average water-content of 37 to 38 per cent, with occasional cheeses verging toward Limburger in texture and flavor with 40 to 42 per cent water, and others in- distinguishable from Cheddar, with water-content as low as 34 per cent. The Wisconsin Cheese-makers Association uses the following score-card for the judging of Brick cheese on a scale of 100 : SEMI-HARD CHEESES 169 Flavor , . . 40 Texture 40 Color 10 Salt . i 5 Style _5^ 100 179. Composition and yield. — The composition of Brick cheese varies within wide limits. The average cheese probably contains from 37 to 39 per cent of water, although many cheeses are above and below this average ; Doane and Lawson x give the fat as 28.86 per cent, pro- teins 23.8 per cent and total ash 4.20 per cent. The composition and yield are both affected by : (1) the moisture-content of the cheese; (2) composition of the milk from which made; and (3) losses during the manu- facturing process. The average yield of Brick cheese is 11 to 13 pounds to 100 pounds of milk. 180. Port du Salut cheese. — The Trappist monks originated this type of cheese in their monasteries in France. Under the name of their community Oka, it has been made and sold widely by the Trappist Fathers of Quebec. In recent years, factories independent of the order have made such cheese both in America and in Europe. The following outline of the making process indicates the close relationship between Port du Salut and Brick cheeses. Whole milk or milk not over one-fifth skimmed is ripened to medium acidity, then heated to 90° to 95° F. according to season and acidity. Rennet enough is 1 Doane, C. F., and H. W. Lawson, Varieties of cheese, de- scriptions and analysis, U. S. Dept. Agr. Bur. of An. Ind. Bui. 146, 1911. 170 THE BOOK OF CHEESE added (see Chapter V) to curdle in thirty to forty min- utes, although some makers shorten the time to twenty minutes. When formed, the curd is cut into small cubes and excess of whey is dipped away. The constantly stirred mass is then heated or cooked to 100° to 105° F. within a period of ten to twelve minutes or according to some makers twenty to thirty minutes. It is allowed to stand a few minutes to settle. Most of the whey is then drawn and the mass is stirred vigorously to prevent fusion of the curd granules. The curd is ready for the hoop when the particles are about the size of grains of wheat and do not stick together when squeezed with the hand. The individual grains of curd should crumble easily between the fingers. The hot curd is transferred directly to the hoops without cooling. For this purpose, a hoop is set upon the table covered with a cloth and the curd dipped into the cloth. The edges of the cloth are then folded over. In this condition the cheese is trans- ferred to the press where gradually increasing pressure begins with 3 to 4 pounds and reaches about 70 pounds. To insure proper shape, cheeses are turned and put into fresh cloths at the end of the first hour and turned subse- quently several times during the pressing period of about twelve hours.1 Port du Salut cheeses are salted by rubbing fine salt on the surface by hand at the rate of 1.2 to 2 per cent of the weight of the cheese. After about two days in the salting process, they are put into the ripening cellars. The cellars are wet, since they reach 90 to 95 per cent relative humidity at a temperature of about 55° F. After two days in the cellar, the cheeses are plunged 1 Ligeon, X., Herstellung des Port Salut Eases, Milchztg. 38 (1909), no. 39, pages 459-460. SEMI-HARD CHEESES 171 into a tank of saturated brine to which a trace of cheese color has been added. As they come out of these tanks, they are yellowish and greasy or slimy. They are re- turned to the shelves where they are rubbed every day with a cloth or by hands wet in brine. After about one week they are again plunged in the brine. Treatment with brine tends to insure a firm rind. The cheeses are rubbed more or less regularly with brine through the whole ripening period. After six weeks, such cheese may be eaten. The cut surface of Port du Salut is creamy in color, may or may not show small holes. In texture it is soft enough to spread readily under pressure without losing its shape in handling. In flavor the cheese is a mild form belong- ing to the Limburger group. Port du Salut cheeses as imported from France usually are firm round cakes about 1^ inches thick, weighing about 3 pounds. CHAPTER XI THE HARD CHEESES THE hard cheeses form a great series of groups, whose most prominent physical character is their firm or hard texture. This is correlated with comparatively low water-content, which is usually between 30 and 40 per cent. Although certain varieties occasionally test above 40 per cent water, this deviation is accompanied by quick ripening and rapid spoilage. These varieties of cheese are staple products with long marketable periods ; therefore they may be handled in large lots, shipped, carted and stored freely without the losses such treat- ment would entail in soft cheese. The retailer frequently buys hard cheese by the ton, not by the cheese or by the box. In making, these varieties are characterized as cooked and pressed cheeses. Although both the heating of a curd and the pressing of a newly made cheese occur among semi-hard forms, these practices appear in their most typical forms in the hard cheeses. The hard cheeses show two types of texture. A cut cheese may appear smooth, free from holes or with a few angular cracks or seams, or it may show round holes or "eyes." In the smooth textured forms every effort is made to prevent gassy fermentations, usually by control- ling the fermentation of the curd in the making process. 172 THE HARD CHEESES 173 When " eyes " are present, the end sought has been a development of a particular form of gassy fermentation which gives this appearance and brings about the char- acteristic ripening texture and flavor. The hard cheeses have been developed in groups of national varieties. The best known of these groups are those which may be represented by English Cheddar, American Factory Cheddar, Danish, the Edam of Hol- land, Swiss and Parmesan with many related varieties in Italy and neighboring countries of southern Europe. 181. The Danish group. — The Danish cheeses are related in appearance and flavor to the English group represented by Cheddar. The demand for butter in Europe has been so great that the Danish cheese-makers have developed skim and part skim varieties largely to the exclusion of the whole milk form. Skillful handling of their process has resulted in a product which has had a very large and appreciative market in England and Germany. 182. The Dutch group. — Edam and Gouda are the two forms of cheese made in Holland and most widely known among other peoples. Both reach America in con- siderable quantities; both are shipped in large amounts to tropical countries. Although attempts have been made to manufacture them in America, no commercial production of these cheeses has been successful. Al- though whole milk grades of these cheeses are known, they are to a large measure part skim in manufacture. The presence of one or both of these forms in every large market in America makes the general facts of their produc- tion of general interest. Parts of a report on experimental work in the making of Edam and Gouda are, therefore, given here. 174 THE BOOK OF CHEESE 183. Edam cheese 1 is a sweet-curd type, made from partially skimmed-milk. It comes to the market in the form of round red balls, each weighing from 3^ to 4 pounds when cured. It is largely manufactured in northern Holland and derives its name from a town famous as a market for this kind of cheese.2 Milk from which one-fourth to one-third of the fat has been re- moved is used. Too great pains cannot be taken in regard to the condition of the milk. It should be fresh, free from every trace of taint ; in brief, it should be in as perfect condition as possible. 184. Method of manufacture. — The following para- graphs give the steps in the manufacture of Edam cheese : Treatment of milk before adding rennet. — The tempera- ture of the milk should be brought up to a point not below 85° F. nor much above 88° F. When the desired temperature has become constant, the coloring matter should be added. Cheese color is used at the rate of 1 J to 2 ounces for 1000 pounds of milk. The coloring matter should, of course, be added to the milk and thoroughly incorporated by stirring before the rennet is added. Addition of rennet to milk. — The rennet should not be added until the milk has reached the desired temperature (85° to 88° F.) and this temperature has become constant. 1 These paragraphs were taken from N. Y. Exp. Sta. Bui. 56, Experiments in the manufacture of cheese ; Part I. The manu- facture of Edam cheese, 1893. See also, Haecker, T. L., Experi- ments in the manufacture of cheese, Minn. Exp. Sta. Bui. 35, 1894. 2 Boekhout, F. W. J., and J. J. O. de Vries, Cracking of Edam, Verslag. Landbouwk.- Onderzoek. Rykslandboupoef stat. (Nether- lands), 20 (1917), pages 71-78, fig. 1. Boekhout, F. W. F., and J. J. O. de Vries, Sur le de"faut "Knijpers" dans le fromage d'Edam, Rev. Gen. Lait, 9 (1913), no. 18, pages 420-427. THE HARD CHEESES 175 When the temperature reaches the desired point and re- mains there stationary, the rennet extract is added. Rennet extract may be used, 4^ to 5 J ounces being taken for 1000 pounds of milk, or enough to coagulate the milk in the desired time, at the actual temperature used. The milk should be completely coagulated, ready for cutting, in about twelve to eighteen minutes from the time the rennet is added. The same precaution observed in making Cheddar cheese should be followed in making Edam cheese with reference to care in adding the rennet, such as careful, accurate measurement, dilution with pure water before addition to milk. Cutting the curd for Edam. — When the curd breaks clean across the finger, it should be cut ; it is cut a very little softer than in the Cheddar process as ordinarily prac- ticed. As stated, this stage of hardness in the curd which fits it for cutting should come in twelve to eighteen min- utes after the rennet is added. First, a vertical knife is used and the curd is cut lengthwise, after which it is allowed to stand until the slices of curd begin to show the separation of whey. Then the vertical knife is used in cutting crosswise, after which the horizontal knife is at once used. Any curd adhering to the bottom and sides of the vat is carefully removed by the hand, after which the curd-knife is again passed through the mass of curd lengthwise and crosswise, continuing the cutting until the curd has been cut as uniformly as possible into very small pieces. Treatment of Edam curd after cutting. — When the cutting is completed, one commences at once to heat the curd up to the temperature of 93° to 96° F. The heating is done as quickly as possible. While the heating is in progress, the curd is kept constantly agitated to prevent settling 176 THE BOOK OF CHEESE and consequent overheating. As soon as the curd shows signs of hardening, which the experience of the worker will enable him to determine, the whey is drawn off until the upper surface of the curd appears, when one should commence to fill the press molds. Filling molds, pressing and dressing Edam. — The molds, which are described later in detail, are well soaked in warm water previous to use, in order to prevent too sudden chilling of curd and consequent checking of sepa- ration of whey. As soon as whey is drawn off, as indi- cated above, one begins to fill the pressing molds (Fig. 27) . The filling should be done as rapidly as possible to prevent too great cooling of curd. When the curd has been put into the molds, its temperature should not be below 88° F. Unless care is taken to keep the curd covered, the portion that is last put into the molds may be- come too much cooled. In making Edam FIG. 27. — Edam cheese on a small scale, it is a good plan cheese mold. , i • , ^1.111 to squeeze the moisture out with the hands as much as possible and then break it up again before put- ting in the molds, when the curd should be pressed into the mold firmly by the hands. The molds should be filled as nearly alike as possible. The cheese should weigh from 5 to 5J pounds each when ready for the press. When the filling of molds is completed, they are put under continual pressure of 20 to 25 pounds for about twenty-five or thirty minutes. While the cheese is being pressed, some sweet whey is heated to a temperature of 125° or 130° F., and this whey should not be allowed to go below 120° F. at any time while it is being used. When the cheeses are taken from their molds, each is put into the warm whey for two minutes, then removed and dressed. For dress- THE HARD CHEESES 177 ing Edam cheese, the ordinary cheese bandage cloth is used. This is cut into strips, which should be long enough to reach entirely around the cheese and overlap an inch or so, and which should be wide enough to cover all but a small portion of the ends of the cheese when put in place. Before putting on the bandage, all rough pro- jections should be carefully pared from the cheese. In putting on, the cheese is held in one hand and the bandage is wrapped carefully around the cheese, so that the whole is covered, except a small portion on the upper and lower surface of the cheese. These bare spots are covered by small pieces of bandage cloth of a size sufficient to fill the bare surface. The bandage is kept wet with the warm sweet whey, thus facilitating the process of dressing. After each cheese is dressed, it should be replaced in the dressing mold, care being taken that the bandage remains in place and leaves no portion of the surface of the cheese uncovered and in direct contact with the mold. The cheese is then put under continual pressure of 60 to 120 pounds and kept for six to twelve hours. 185. Salting and curing Edam. — There are two methods which may be employed in salting, — dry and wet. In dry-salting, when the cheese is finally taken from the press, it is removed from the press mold, its bandage is removed completely, and the cheese placed in another mold, quite similar, known as the salting mold. Each cheese is placed in a salting mold with a coating of fine salt completely surrounding it. The cheese is salted in this way once each day for five or six days. Each day the cheese should be turned when it is replaced in the mold, so that it will not be rounded on one end more than the other. In the method of wet-salting, the cheese is placed in a 178 THE BOOK OF CHEESE tank of salt brine, made by dissolving common salt in water in the proportion of about 1 pound of salt to 2| quarts of water. Each cheese is turned once a day and should be left in the brine seven or eight days. When the cheese is taken from the salting mold or salt bath, it is placed in warm water and given a vigorous, thorough brushing in order to remove all slimy or greasy substances that may have accumulated on the outer surface. When the surface is well cleansed, the cheese is carefully wiped dry with a linen towel and placed upon a shelf in the cur- ing-room. In being put on the shelves, the cheeses should be placed in contact so as to support one another, until they have flattened out at both ends so much that they can stand upright alone. Then they are moved far enough apart to allow a little air space between them. Another method of securing the flattened ends is to sup- port each cheese on opposite sides by wedge-shaped pieces of wood. After being placed on the shelves in the curing- room, they are turned once a day and rubbed with the bare hand during the first month, twice a week during the second month and once a week after that. When any slimy substance appears on the surface of the cheese, it should be washed off at once with warm water or sweet whey. The special conditions of the curing-room will be noticed in detail below. When the cheeses are about two months old, they can be prepared for market in the following manner: They are first made smooth on the surface by being turned in a lathe or in some other manner, after which the surface is colored. For coloring, some carmine is dissolved in alcohol or ammonia to secure the proper shade, and in this color-bath the cheeses are placed for about one minute, when they are removed and allowed to drain, and as soon as they are dry the outside of each THE HARD CHEESES 179 cheese is rubbed with boiled linseed oil, in order to pre- vent checking. They are then wrapped in tin-foil, which is done very much like the bandaging. Care must be taken to put on the tin-foil so that it presents a smooth, neat appearance. The cheeses are finally packed in boxes, containing twelve cheeses in each box, arranged in two layers of six each with a separate partition for each cheese. 186. Equipment for making Edam cheese. — Careful attention must be given to the moisture and temperature of the curing-room. This room should be well venti- lated, quite moist and its temperature kept between 50° and 65° F. These are conditions not easy to secure in any ordinary room. Some form of cellar is best adapted for these conditions. The amount of moisture can be determined by an instrument known as a hygrometer. In a curing-room suited for Edam cheese, the moisture should be between 85 and 95 per cent, or a little short of saturation. When the temperature is between 50° and 65° F., the moisture is between 85 and 95 per cent if the wet-bulb thermometer is from 1 to 2° F. (or J to 1° C.) below the dry-bulb thermometer. Cheese will check or crack and be spoiled for market, if the degree of moisture is not kept high enough. Aside from the molds, press and salting vat, the same apparatus that is used in making Cheddar can be used for Edam cheese. The pressing mold is turned preferably from white wood or, in any case, from wood that will not taint. Each mold consists of two parts; the lower constitutes the main part of the mold, the upper portion is simply a cover. The lower portion or body of the mold has several holes in the bottom, from which the whey flows when the cheese is pressed. Care must be taken 180 THE BOOK OF CHEESE to prevent these holes being stopped up by curd. This part of the mold is about six inches deep and six inches in diameter across the top. The salting mold has no cover and the bottom is provided with only one hole for the out-flow of whey; in other respects it is much like the pressing mold. 187. Qualities and yield of Edam cheese. — The flavor of a perfect Edam cheese is difficult to describe. It is mild, clean, and pleasantly saline. In imperfect Edams, the flavor is more or less sour and offensive. In body, a perfect Edam cheese is solid, rather dry and mealy or crumbly. In texture, it should be close and free from pores. In the experiments here reported the amount of fat in 100 pounds of the partially skimmed-milk varied from 2.45 to 3.20 pounds and averaged 2.77 pounds. Of this amount, from 0.30 to 0.51 pound of fat was lost in the whey, with an average of 0.39 pound. The yield of cheese from 100 pounds of milk varied from 9.60 to 11.82 pounds and averaged 10.56 pounds. 188. Gouda cheese. 1 — This Dutch variety is a sweet- curd cheese made from whole milk. In shape, the Gouda cheese is somewhat like a Cheddar with the sharp edges rounded off and sloping toward the outer circumference at the middle from the end faces. They usually weigh 10 or 12 pounds, though they vary in weight from 8 to 16 pounds. They are largely manufactured in southern 1 Paragraphs taken from N. Y. Exp. Sta. Bui. 56, Experi- ments in the manufacture of cheese ; Part II. The manufacture of Gouda cheese, 1893. See also, Hay ward, H., Method of making Gouda cheese, Pa. Exp. Sta. Kept. 1890, pages 79-81, and Haecker, T. L., Experiments in the manufacture of cheese, Minn. Exp. Sta. Bui. 35, 1894, and Monrad, J. H., in N. Y. Produce Rev. 25 (1907), no. 8, page 336, where a home process of making this cheese is given. THE HARD CHEESES 181 Holland, and derive their name from the town in which they were first made. Fresh sweet milk that has been produced and cared for in the best possible manner should be used. 189. Method of manufacture. — The processes of manufacturing Gouda cheese are as follows : Treatment of milk before adding rennet. — The tempera- ture of the milk should be brought up to a point not below 88° F. nor much above 90° F. When the desired tempera- ture has been reached and has become constant, the color- ing matter is added. One ounce of cheese color for about 1200 pounds of milk may be used. The coloring matter should be thoroughly incorporated by stirring before the rennet is added. Addition of rennet to milk. — The rennet should not be added until the milk has reached the desired tempera- ture (88 to 90° F.) and this temperature has become con- stant. The milk should be completely coagulated, ready for cutting, in fifteen or twenty minutes. The same precautions should be used in adding rennet as those previously mentioned in connection with the manufac- ture of Edam cheese. Cutting the curd. — The curd should be cut when it is of about the hardness generally observed for cutting in the Cheddar process. The cutting is done as in the Ched- dar process except that the curd is cut a little finer in the Gouda cheese. Curd should be about the size of peas or wheat kernels when ready for press and as uniform in size as possible. Treatment of curd after cutting. — After the cutting is completed, heating and stirring is begun at once. The heating and constant stirring is continued until the curd reaches a temperature of 104° F., which should require 182 THE BOOK OF CHEESE from thirty to forty minutes. When the curd becomes rubber-like in feeling, the whey should be run off. The whey should be entirely sweet when it is removed. Pressing and dressing Gouda. — After the whey is off, the curd is put in molds at once without salting (Fig. 28). Pains should be taken in this process to keep the temperature of the curd as near 100° F. as possible. Each cheese is placed under continuous pressure amount- ing to ten or twenty times its own weight and kept for about half an hour. The first bandage is put on in very much the same manner as in Edam cheese making. The cheese is then put in press again for about one hour. The first bandage is then taken off and a second one like the first put on with great care, taking pains to make the bandage smooth, capping the ends as before. The cheese is then put in press again and left twelve hours or more. Salting and curing. — When Gouda FIG. 28. — Gouda cheese is taken from the press, the band- cheese mold. . . . . . , , „ age is removed and it is placed tor twenty-four hours in a curing-room like that used for Edam cheese, as previously described. Each cheese is then rubbed all over with dry salt until the salt begins to dissolve, and this same treatment is continued twice a day for ten days. At the end of that time, each cheese is carefully and thoroughly washed in warm water and dried with a clean linen towel. The cheeses are then placed on the shelves of the curing-room, turned once a day and rubbed. The temperature and moisture are con- trolled as described in the curing process of Edam cheese. If the outer surfaces of the cheese become slimy at any time, they are carefully washed in warm water THE HARD CHEESES 183 and dried with clean towels. Under these conditions, cheese ripens in two or three months. 190. Equipment for Gouda cheese. — The molds, press and curing-room are the only equipment needed in the making of Gouda cheese that differ from that employed in making Cheddar cheese. The mold used for Gouda cheese consists of two portions, which .are shown sepa- rately in Fig. 28. These molds are made of heavy pressed tin. The inside diameter at the middle is about 10 inches, that of the ends about 6 J inches. The height of the mold is about 5^ inches, and this represents the thickness of the cheese, but by pushing the upper down into the lower portion, the thickness can be decreased as desired. 191. Composition and yield of Gouda. — In work with milk averaging 4.2 per cent of fat there were lost in the whey from 0.29 to 0.43 per cent with an average of 0.35 per cent of fat. The loss of fat appears to be not much greater than the average loss met with in cheese factories in making Cheddar cheese. From 100 pounds of milk, there were made from 11.60 to 13.35 pounds of green cheese, with an average of 12.50 pounds. The per- centage of water in the experimental cheese varied from 41.25 to 45.43 per cent and averaged 43.50 per cent. CHAPTER XII CHEDDAR CHEESE-MAKING CHEDDAR is the best known cheese throughout the United States and the one most commonly made in factories. The Cheddar process was brought to America by English immigrants. Similar to Cheddar cheese are Pineapple, English Dairy, Sage cheese, skimmed -milk and California Jack cheese made in this country, and Derbyshire, Leicestershire, Wensleydale and Cheshire made in England. The Cheddar cheese process as employed in the factories to-day has been modified and improved since it was first introduced into this country by the early immigrants. The following description1 includes only the practices as found in the factories to-day if whole milk is used. Skimined-milk Cheddar cheese is discussed later. 192. The lot-card. — The Cheddar process involves several hours of manipulation and includes many details which should be closely and accurately observed and recorded. The necessity of carrying observations of Several different factors at the same time makes a scheme of recording data essential to convenient work. For this purpose, a lot-card for Cheddar cheese is introduced here and the pages given to particular factors are in- dicated in the space intended for the recording of observa- 1 The authors acknowledge here the helpful suggestions and criticisms of G. C. Button, New York State Cheese Instructor. 184 CHEDDAR CHEESE-MAKING 185 & 186 THE BOOK OF CHEESE tions. The manufacture of Cheddar cheese is a compli- cated process, because several factors must be given attention at the same time. A careful record of the observations of each step in the successive handling of each lot of milk puts the operator in possession of a per- manent record of his experience. This record has several uses. It may help to convince patrons of the importance of eliminating faults in the milk ; it furnishes the cheese- maker a cumulative record of his experiences in handling milk with special qualities, such as high or low fat-content, over-acidity or taints. Since Cheddar ripening covers a period of weeks and months, no operator can remember particular lots of milk sufficiently well to be able to use his experience on the interpretation of the qualities found in the ripened product. 193. The milk. — It is the usual practice to deliver the milk to the cheese factory each morning (Fig. 29). The night's milk is cooled and kept clean and cold until de- livered at the factory. It is advisable not to mix the cold night's milk and the warm morning's milk, but to deliver them in separate cans to the cheese factory at the same time. The milk is weighed, sample for fat test taken and then run into the vat (Fig. 30). The receiving or taking in of the milk is one of the most important parts of the cheese factory work. It is practically as important as the actual manufacturing of the cheese. Any milk high in acid or with a bad flavor should be avoided. It is often bad policy to reject the milk, for a neighboring factory will accept it and the factory not only loses the milk but also the patron. Factories should have an agreement to prevent this. The acidity can be determined by the acid test, but the detection of flavors must be made by the cheese-maker himself with the aid CHEDDAR CHEESE-MAKING 187 21 CHEESE. This card must remain with lot from the milk room until the finished product is ready to leave the building, then it should be handed to instructor. MAKING Day and Date . Vat Milk Used Milk Appearance of Milk Taste Weather conditions. Total pounds % fat Ibs. fat .% solids not fat Ibs. s. n. f. .% casein Ibs. casein. Starter Kind used Flavor Acidity Amount used % used- Minutes Time of adding starter.... \ adding rennet .... coagulation cutting ._ turn'g on steam., turn'g off steam dipping packing ._ milling salting hooping pressing. dressing Total time from 1 setting to pressing J " % Acid In Milk when received before adding starter. after adding starter.... when rennet added In Whey after curd is cut at dipping._ at packing at milling at salting Temperature of milk when received when starter added.... when rennet added .... when whey removed.... at pressing Rennet Test when milk received.... after adding starter.... when rennet added Hot Iron Test at dipping at packing at milling at salting Condition of Curd when cut when packed when milled when salted when pressed Amount per 1000 Ibs. milk Total Amount Color Rennet Salt % fat in Ibs. fat esti- whey mated so lost. % of total milk fat lost in whey Assisted by If comments are added on reverse side, put cross here Work and Observations by YIELD Day and Date Time Serial Weight of cheese when removed from press to curing room,.— Ibs. No. Ibs. milk for Kind of cheese made Ibs. cheese per one Ib. cheese. 100 Ibs. milk Ibs. cheese for one No. of cheese made. Ibs. cheese for one Ib. fat in milk. Ib. total solid If comments are added on reverse side put cross here Work and observations by - Arranged by W. W. Hall. 188 THE BOOK OF CHEESE | CHEDDAR CHEESE-MAKING 189 of smell and taste. Many of the bad flavors in the cheese can be traced to the poor quality of the milk. One of the worst qualities in milk and cheese is the presence of gas-producing organisms.1 Any milk which shows gassy fermentation should be rejected, for it is difficult to make cheese from this and at best there will be a large loss during the manufacturing process. The cheese may have a bad flavor and develop " pin-holes " and in extreme cases may puff up like a ball. The person receiving the milk should talk to the farmers or dairy-men about the proper care of the utensils and milk. He must see that the cans are kept clean. One very bad practice is to deliver milk and take home whey in the same cans. The cans, as they are brought back from the cheese factory full of whey, are often left in the barn or near a hog-pen until the whey is fed. Unless such cans are emptied immediately on returning to the farm and then rinsed out with cold water, thoroughly washed and scalded, bad flavors may develop in the cheese. It is thought that this causes " fruity " or sweet flavor, which resembles that of fruits such as raspberries, strawberries or pineapples. 194. Ripening the milk. — A slight development of acidity is required : (a) to obtain the formation of a firm curd; and (b) to establish immediate dominance of a desirable type of lactic organism which will produce the large amount of acid required later in the cheddaring process. The development of this acidification before the addition of rennet is known as the ripening of the milk. The extent of ripening advised by different 1 Russell, H. L., Cheese as affected by gas-producing bacteria, Wis. Exp. Sta. Kept. 1895, pages 139-146. Marshall, C. E., Gassy curd and cheese, Mich. Exp. Sta. Bui. 183, 1900. 190 THE BOOK OF CHEESE schools of makers has varied from an acidity of 0.20 of 1 per cent or even slightly higher percentage titrated as lactic acid, to about 0.17 of 1 per cent as now preferred by some of the most successful groups of workers. The ripeness of the milk can also be determined by the use of the rennet test. The milk may be ripened by allowing the lactic organisms already present in the milk to develop naturally. This requires considerable time and while the lactic acid-forming bacteria are developing, other and undesirable fermenta- tions may be taking place, so that the good results which should follow the uninterrupted development of the lactic acid-forming organisms are lost. Starter is commonly used to produce the desired ripening of the milk. (For the preparation of starter see Chapter IV.) Some makers put the starter into the empty vat (Fig. 31) and add the milk as it is received; others add it to FIG. 31. — Steel cheese vat. the total volume of cold milk and then begin to heat it. Whenever the starter is used, it should be strained to remove lumps. These lumps might cause a mottled color in the cheese. The best practice calls for an acidity or a rennet test of the mixed milk after it has been brought to the setting temperature in the vat. With milk tested at this stage and the volume of milk in the CHEDDAR CHEESE-MAKING 191 vat known, the cheese-maker is able to calculate closely the amount of starter needed. When the quantity of starter to use is in doubt, the amount added should be under rather than over the estimate, since the need of more can be determined by making frequent ren- net and acid tests in a very few minutes without damage to the cheese. If too much starter has been used, acid or sour cheese is usually obtained, with loss in market quality. An over-development of acidity at any stage of the man- ufacturing process affects the flavor, body and texture, color and finish of the cheese. The product is known as a sour cheese, and can usually be identified by its sour taste and smell. A sour cheese while curing will seldom develop a normal Cheddar flavor and the texture will be hard and harsh and very brittle. The body will not be smooth but harsh and grainy. The over-development of acid will show by fading or bleaching the color. A sour cheese usually leaks whey for a few days after being placed on the curing-room shelves. Ripening the milk is one of the most important parts of cheese-making. Proper ripening places the acid fer- mentations under the control of the cheese-maker so that he may know what results will follow his labors. The operator can control the acidity while ripening the milk, but after the rennet is added all control of the acidity is lost. From that time, the moisture must be regulated in proportion to the acidity. Before setting, the milk should be ripened to such a point as to leave at least two and one-half hours from the time that the rennet extract is added until the acid de- velopment has reached the stage at which it is necessary to remove the whey. By the acid test the milk may vary 192 THE BOOK OF CHEESE from 0.16 to 0.18 of 1 per cent, but no definite statement can be given for the rennet test. This can be determined only by comparison from day to day. For opera- tion of rennet test see Chapter V. During this period of two and one-half hours, the curd is formed, then cut, and the temperature is raised from 84° or 86° F. (the temperature at which the rennet extract is added) to about 98° to 100° F. The curd must be kept agitated so that the particles will not mat together; this is necessary to obtain sufficient contraction of the particles of curd with the proper reduction of water-content. If the milk becomes too ripe (too sour) before the rennet is added, there will not be sufficient time for these steps to take place naturally. In such cases special means are re- quired to firm the curd. These result in a loss of both quality and quantity of cheese. On the other hand, if the milk is not ripened, but the rennet extract added, regardless of the acid development, one of the important natural forces for expelling the moisture is lost. The time required for the particles of curd to contract is much prolonged, the expulsion of whey is usually inadequate and the curd remains in a soft or wet condition. Using too much starter is almost equally bad, for although it hastens the making process, it produces a sour or acid cheese. 195. Setting or coagulating. — The milk for Cheddar cheese-making is heated to 86° to 88° F. or occasionally a slightly lower temperature. This temperature is found by experiment to give the texture of curd most favorable for the desired results. Although some cheese-makers work as low as 84° F., the texture of such curd is too soft and coagulates too slowly. The very slight change of 2°F. produces curd which coagulates more quickly and is tougher and firmer. CHEDDAR CHEESE-MAKING 193 If the cheeses are to be colored, the color should be added after all the starter. It should be thoroughly and evenly mixed with the milk to insure an even color in the cheese. If the color is added before the starter, there are likely to be white specks in the cheese, on account of the coagulated casein in the starter. The amount of color to use depends on the tint desired in the cheese. It varies from J to \ ounce to 1000 pounds of milk for a light straw color to \\ to 2 ounces for 1000 pounds of milk for a deep red color. Enough rennet should be used to produce a curd firm enough to cut in twenty-five to thirty-five minutes. The necessary amount will vary with the strength of the rennet extract itself, with the acidity, the temperature, the nature of the lot of milk, and with the individual aims of the maker in which he adjusts the other factors to his preferences as to rapidity of rennet action. With the usual commercial extract, the needed amount ranges from 2.5 to 4 ounces for 1000 pounds of milk. As for all varieties of cheese, the rennet extract should be diluted in cold water at about one part rennet to forty parts water and thoroughly stirred into the milk. (See Chapter V.) 196. Cutting. — The object of cutting is to obtain an even expulsion of the moisture from the curd. The curd is cut as soon as it becomes firm enough. To determine this, various tests may be used. Some opera- tors test it by pressing it away from the side of the vat, considering it ready to cut when it separates cleanly from the metal. The test most commonly used is to insert the index finger obliquely into the curd, then to start to split the curd with the thumb and finally to raise the finger gently ; if ready to cut, the curd will split cleanly 194 THE BOOK OF CHEESE over the finger and clear whey will separate to fill the opened crack. Another arbitrary but more or less satis- factory rule is that the time from adding the rennet until cutting should be two and one-half times that from the addition of rennet until the first sign of coagulation is observed. The condition of the curd itself is the best guide to show when it is ready to cut. The condition of the curd is constantly changing, so that in a large vat, if the cutting is not begun until the curd is in the best condition, by the time the last of the curd is cut it will be too hard or firm. It is better to begin while the curd is a trifle too soft so that the cutting will be taking place while the curd is at the proper stage. At best the last of the curd may become too hard. If too hard, it will break ahead of the knife instead of cut. Breaking causes more fat loss than cutting because there is more surface exposed and hence more fat globules. The softer the curd when cut, the quicker and easier the moisture can be expelled. If the curd is cut when soft, care must be exercised not to stir it too hard immediately after cutting. Soft curd breaks very easily. When the curd is cut soft and then stirred vigorously, there is a larger loss of fat than when the curd becomes hard before it is cut. Two knives are used to cut the curd. (See Fig. 11.) These knives may have either wire or blades for cutting. The space between the wires or blades varies from A to f inch. Knives used should have blades or wires close enough together to cut the pieces as small as desired, without a second cutting. When the curd has to be cut a second time it usually results in pieces of uneven sizes, be- cause the pieces already cut cannot be evenly split in two. CHEDDAR CHEESE-MAKING 195 One set of knives has horizontal and the other per- pendicular blades or wires. The curd is cut the long way of the vat with the horizontal knife and lengthwise and crosswise with the perpendicular knife so that the result is small cubes or oblongs of curd. Some cheese-makers prefer to use one knife first and some the other, but the result should be a curd cut into pieces of uniform size. The smaller the particles of curd or cubes are cut, the quicker the curd will firm up or cook. If not cut uniformly, the changes taking place later in the curd particles will not be uniform, — the small pieces will be hard and dry while the large ones will be soft and mushy. Care should be taken to let the knife cut its way into the curd (Fig. 32). If the knife is pushed into the curd, FIG. 32. — ^The proper way to put the knife into the curd. it will break it and cause a large loss of fat. The same is true when taking the knives out of the curd. The loss of fat due to cutting is very similar to the loss of sawdust when sawing a board. It may be considered a necessary evil. The loss due to cutting is about 0.3 of 1 per cent of fat in the whey and the loss of casein about 0.1 of 1 per cent in the whey. 197. Heating or "cooking" the curd. — After the curd is cut, the pieces (cubes) rapidly settle to the bottom 196 THE BOOK OF CHEESE FIG. 33. — Acme curd rak( of the vat and tend to mat together. To prevent this, the curd must be kept stirred. When stirring first begins, the curd is soft and very readily broken. Some cheese- makers prefer to stir by hand for the first few minutes after cutting, while the curd is soft. The importance of careful handling can hardly be over- emphasized. No matter how well the curd has been cut, if the stirring is performed in a careless manner in the early stages, it will be broken into uneven sized pieces and a considerable loss of fat will result. A wooden hayrake or a McPherson curd agitator (Figs. 33, 34) may be used to stir the curd. Me- chanical curd agitators are used in some cheese factories. There are several makes. (See Fig. 35.) These agitators save much hand labor, although some stirring by hand must be done in connec- tion with them. The mechanical agitators do not stir the curd in the corners of the vat ; this must be done with the hand rake. It is the usual practice to stir the curd immediately after cutting for five to ten minutes before the mechanical agitators are used. This is necessary to give the curd a slight chance to firm as the mechanical agitators tend to FIG. 34. — McPherson curd agitator. CHEDDAR CHEESE-MAKING 197 198 THE BOOK OF CHEESE break it up. After cutting, a thin film forms on each piece of curd. This film holds the curd particles, especially the fat. Breaking the films on the cubes causes loss of fat. If lumps form at the early stage, by matting of the curd particles, violent stirring is required to separate them. When such lumps are broken up, new cleavage lines are formed with loss of fat, because the original films surrounding the soft curd fuse so firmly that the curd cubes do not separate but actually break. New surfaces are thus formed with consequent fat loss. Rapid shrinkage with expulsion of whey takes place during the first few minutes of gentle agitation. Before any heat is applied to the vat, sufficient whey should have separated or formed to float each piece of curd separately. This will require ten to fifteen minutes from the time of cutting. Thus far the first of three distinct factors which expel the moisture from the curd has been considered : (1) the action of the rennet; (2) the development of the lactic acid; and (3) the application of heat. These forces must have time to act naturally. If heat is applied too soon after the curd is cut or if the temperature is raised too rapidly, it causes a thick film to form on the pieces of curd which interferes with the escape of the whey. The outside of the curd becomes firm but the inside re- mains very soft. A curd which is cooked on the outside only feels firm when stirred by hand in the whey, but when a handful is squeezed the soft centers are noticed. To firm such curd masses requires violent stirring, which will break the thick tough film. This allows the mois- ture to escape and also increases the fat loss. The rapidity of heating should depend on the condition of the curd and the amount of acid developed. The heat should keep pace with these. When ready to raise the CHEDDAR CHEESE-MAKING 199 temperature, the least amount of steam possible should be allowed to pass through the valve. This should raise the temperature very gradually. If heat is applied too quickly at first, it will cause the curd to lump. A safe rule is to raise the temperature one degree in the first five minutes after the steam has been turned on. The heating should progress slowly until the whole mass of curd in the vat has reached a temperature of 90° to 92° F. The usual temperature to which the curd is heated or cooked is 98° F. to 100° F. The lower the temperature that can be used and properly firm the curd, the better will be the body of the cheese. If the curd is heated too high, it will become hard, which causes a dry hard "corky" cheese. After this temperature has been reached, there is not such a tendency for the curd particles to stick together nor are they so easily broken in stirring. It should require, under normal conditions, not less than thirty to forty-five minutes, from the time rH d Ci O I-H co 3 °3 » « !>• !>• »O CO TjH CO of ^T co" tO CO 00 i— i to CO CO i-l i-l i-l i— i "^ CO (N (N 1-1 00 00 CO CO !>• tO CD t> CO CO lO CO CO oT oT co~ l> »O O 00 00 CO 00 CO*" r-T CO" C eogcsT^N t^* CO O5 O^ 3d Tt^ 00 I-H 00 o 3 O ^ ^ I-H la 'I "I °. ^ .S 1-3 d 55 o cs Sl^.1 320 THE BOOK OF CHEESE of being manufactured into cheese. There is about the same number of milch cows in New York and Wisconsin. However, Wisconsin is credited with more cheese in 1909 than New York ever produced and this output probably will increase, as there are considerable areas of undeveloped agricultural land in Wisconsin. It is also interesting to note that Ohio is falling off in cheese production. This may be due to the increased demand for market milk. On the other hand, production has increased in Pennsylvania. 304. Exportation and importation of cheese by the United States. — The accompanying table shows the ex- Millions Pounds 300 200 150 100 50