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 common 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 Penicillium (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 perhaps 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 NeufchÂtel curdled by souring and rennet together finds its basis in NeufchÂtel curd also but modifies the final product until the familiar flavor and texture of the unripened form are no longer recognizable. 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 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.42 One of these forms, hand cheese,43 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 temperature 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 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, principally for local use. Production of this cheese on a factory basis is now being attempted. The steps in manufacture are about as follows:44 (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.141. Appetitost (Appetite cheese).—A Danish buttermilk cheese is made under this name. Sour buttermilk is heated, by some to boiling temperature but others (Monrad45) 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 NeufchÂtel, French process.—NeufchÂtel as a ripened cheese is made rather widely in France but it is produced on an especially large scale in Seine-Inferieure.46 Some factories use whole milk, or milk with added cream, others skimmed-milk.47 The whole-milk brands of NeufchÂtel 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 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 essentially the same as the American factory process of making NeufchÂtel. 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 receives 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 carefully 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 four days at first, then allowed to stand for a longer period.

When ripe, a NeufchÂtel cheese so made weighs about 125 grams. One liter of milk makes 225 grams of such cheese. The ripening of NeufchÂtel has never been fully studied, but a series of these cheeses were obtained by one of the authors; cultures were made and examined.48 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 MazÉ 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.49 These facts justify the conclusion that ripened NeufchÂtel 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.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 NeufchÂtel 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 abandonment of these undertakings, until at the outbreak of the European war in 1914 but one factory was making Camembert and that only on an experimental scale. Meanwhile 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-establishment 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.50—These cheeses are made in sizes 2½ to 4½ inches in diameter and 1¼ to 1½ inches in thickness. They are ripened by the agency of molds and bacteria which form a felt-like rind over their whole surface, ?16 to ? 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 completely 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 ripening of Camembert is finished in wooden boxes which protect the cheeses from breaking after they become soft and during the market period.

146. Conditions of making and ripening.—These processes depend on a very close adjustment between the composition 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. Work on a factory basis calls, however, for the installation 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 and windows with movable sash. The equipment installed 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 convenient 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 are usually made of 2-inch lumber, Draining mat for Camembert cheese. Fig. 19.—Draining mat for Camembert cheese. 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, 4? inches in diameter with three rows of holes about ?12 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 process51 is summarized as follows (Thom, 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 phenolphthalein 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 lb. milk (10-15 c.c. per 100 lb. milk) produces a curd of proper texture.

Curdling time.—To reach the proper condition for handling, 1¼ to 1½ hours or longer is required. This is indicated by the onset of "sweating" or the separation 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 possible 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 dipperful 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 is used. Cheeses drain by gravity. They stand unturned 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 quality 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 organism (Streptococcus lacticus) in numbers sufficient to suppress 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 temperatures of handling are such as to favor this group of organisms 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.

149. Ripening the cheese.—The cheese is now ready for the ripening rooms (Fig. 20). For this process temperatures between 52° and 58°F. are desirable; lower temperatures only delay the process; higher temperatures favor undesirable fermentations. The cheeses rest upon coarse matting (Fr. clayons) consisting of round wooden rods about the size of a pencil separated 1-1¼ inches and held in position by wire strands. Assuming 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 evaporation 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 inoculation 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 hyphÆ through the outer 2 mm. (?12 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,52 a softening of the curd is first directly detectable under the rind. This is preceded by the disappearance of the acidity of the curd, which progresses 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 enzymes secreted by the mycelium of the Penicillium Camemberti 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 fruiting 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.

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 outside these limits are usually associated with less desirable qualities. The approximate limits and characters outlined for Camembert still leave a considerable latitude for variations in practice which characterize the output of particular factories in a producing group. At one 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 well covered with yellow-orange viscid slime53 but is 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 brevicaule.

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 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 ventilation 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 below 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 unfavorable.

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 package represents (box, wrapping and label) at least 1½ 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 character of the fully ripe cheese makes provision of an adequate 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 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.54—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 1¼ inches; in diameter, 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 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 particular 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 "d'Isigny," 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 Camembert group is called, from its place of origin, Coulommiers. This form is made at the same thickness as Camembert and about 5¼ inches in diameter. It appears as either a ripened or unripe cheese. As a ripened cheese, Coulommiers 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) NeufchÂtel group of cheeses comprises the best known forms with the acid flavor. These cheeses are very perishable in nature. On the other hand, Coulommiers as eaten fresh can be held and used over a much longer time without loss. Coulommiers55 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 outside, and not throughout the mass as in cottage cheese or NeufchÂtel. 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 tangible merit for manufacture and use on the farm in many sections of America.