350 CHEESE stantly floating in the air and attaching them- selves to and developing in any matrix capable of yielding them nourishment ; and as milk is one of the most delicately sensitive of all fluids, the most scrupulous cleanliness should exist in every part of a cheese dairy. The vessels for containing the milk and its products must al- ways be scalded with boiling water as soon as they are emptied, and all the utensils should regularly be subjected to the same treatment. The pastures and all the food and drink of the cows ought to be free from all products of fungoid putrefaction or fermentation of what- ever kind ; therefore stagnant water or low, sour land should not be suffered in pastures de- voted to the grazing of milch cows, and mouldy food should be strictly excluded from their diet. Most of the cheese in the United States is now made at factories, which are carried on by associations of farmers who employ a man- ager. The usual practice is to send the milk to the factory every night and morning, keeping it as cool as practicable during transporta- tion. The process of making cheese with the use of rennet which will now be described is that which is followed by the best cheese makers in this country, and is very nearly the same as that by which the celebrated Cheddar cheese is made, in Somersetshire, England. The evening's milk is placed in cool- ing vats so that it will be brought to a tempera- ture of about GO by the following morning, when the morning's milk is added and the tem- perature raised to 80. This is effected in a manner the most efficient, at the same that it avoids overheating any portion of the milk. A large vat contains the milk, which is gently and equally heated by a water bath, which re- ceives its heat from the circulation of warm water furnished from a cylindrical reservoir heated by a concentric flue placed beneath the vat, or by water contained in a coil of pipe, and heated in a fire box near by. When the milk has reached 80 a sufficient quantity of rennet is stirred into it to produce coagulation in about 40 minutes. It is customary with the Cheddar cheese makers to add sour whey in quantity according to the condition of the milk, adding little or none if any acidity has been de- veloped in it. The whey is used for the pur- pose of hastening the development of lactic acid, because it is then found that there is less liability to that species of fermentation which results in gaseous and other objectionable products. It is a practice that has not been general in this country, but many of the best cheese makers are now adopting it. When the curd has become sufficiently firm, which may be known by its dividing with a smooth frac- ture when the finger is passed through it, it is cut with curd knives, one set of which have perpendicular and the other horizontal blades, into small cubes of from a quarter to a half inch in diameter. The contraction of the curd then takes place more rapidly, expressing the whey; and in about 20 minutes it becomes quite firm, when it is broken up by means of an instrument called a wire shovel breaker into smaller pieces, and the temperature is raised to 98, the contents of the vat being gently stirred to prevent packing of the curds upon the bottom. When the curd has become sufficiently firm for the operation, and the whey has attained a certain degree of acidity, con- ditions which can be learned only by expe- rience, it is drawn off by a large spout as rap- idly as possible, and the curd is heaped in one end of the vat, which is elevated to facilitate the draining. Exposure to the air hastens the development of lactic acid. In 15 or 20 min- utes the particles of curd will have become coherent and form a partially solid mass, which is then cut into pieces and turned over and left until firm enough to break into pieces without danger of expressing the buttery par- ticles, which would be the case if the process were attempted too soon. It is then taken out, placed in a cooler, broken into thin flakes, and spread out to cool still further. In about 20 minutes it is turned over and left until it at- tains a peculiar mellow and flaky condition, well known to the experienced cheese maker. By this time its temperature has been reduced to about 70, and it is put into a hoop and press- ed gently for 10 or 15 minutes, to express more of the whey, by which a too rapid fer- mentation is prevented. It is then taken out and cut and broken into pieces about the size of peas by means of a curd mill, after which it is salted. In England 1 Ib. of salt is used to 56 Ibs. of curd ; but in the United States more salt is used from 2$ to 3 Ibs. to 100 Ibs. of curd partly because American dairy men do not drain their curds or express the whey from their cheeses as much as the English. The changes that produce the aroma and flavor of cheese may be produced in less time, or at least may to a certain extent be imitated, by using a large amount of salt and keeping the curing rooms warm. The flavor, however, is always rendered inferior by such means, and irritating and unwholesome properties are engendered. After the salt has been well incorporated the curd is again put into the hoop, a cloth being placed upon the top and bottom, and sometimes around it. It is kept under pressure for 20 or 24 hours, and is then taken out, and any sharp edges that may have been made in pressing pared off. It is then turned and placed in the press again, and generally, especially if the cheese is a large one, bandaged, and kept there for one or two days longer. In many of the factories in this country, however, only 24 hours is allowed for pressing, because of the number that are made. The temperature at which it goes to press is a matter of great importance, because if too high, fermentation with evolution of gas is liable to take place and make the cheese porous. The temperature at which Cheddar cheese goes to press isbetmvn 60 and 65. Care should be taken during the operation that the buttery particles are not
