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 characteristic 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 to 2 per cent of salt, without an objectionably salty taste. This cheese is commonly sold by measure, sometimes in molds or cartons. The manufacture of all forms of cottage cheese has been largely superseded by the making of skimmed-milk Neufchâtel or Baker's cheese.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, however, 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 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 recoagulate 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 collected[34] 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.