FIG. 163.—BUTTERINE TRUCK.
Acidity.
—The “sourness” or acidity of the milk can be determined by taste or smell, but not accurately. A test is necessary to determine the exact condition of the milk when purchased.
When milk contains six-tenths of one per cent acid, the most desirable point has been reached, as then it imparts the best flavor to the goods. If more than six-tenths of one per cent acid is used the flavor is not as good. This is also the case if a lower percentage of acidity is used. Hence the milk or cream should be brought to this exact degree of sourness before using.
To determine this accurately, it is necessary to do it by a test, as milk may be three-tenths of one per cent acid before it is perceptible to the taste or smell. Milk that would pass as sweet by taste or smell will show two-tenths of one per cent acid.
The test to determine this is simple. Any chemist is able to furnish all alkali solution and the necessary neutralizer of proper strength. The usual way, however, is to use what is known as Farrington’s tablets, prepared by Prof. Farrington of the Wisconsin Dairy School. These tablets are dissolved in water, a convenient strength being five tablets to fifty cubic centimeters of water. The solution is mixed with the milk to be tested and shaken; the acid in the milk acting upon the alkali of the solution immediately turns the milk to a pink color and the amount of the solution required to produce the pink color determines the acidity of the milk.
Milk in Butterine.
—Cleanliness is the all-important factor, since milk is easily contaminated by foreign flavors and germ life. Milk readily absorbs the odors given off by articles placed in the same room. Only pure and absolutely sweet milk and cream should be used, but as absolutely pure milk, though sweet, is difficult to secure, it becomes necessary to adopt some method whereby the condition of such milk can be righted.
Careless milkers care little whether hair, dirt, dust, etc., drop into the pails while milking, thinking that in straining the milk, all particles and impurities are removed. It does remove most particles, but the germs which were clinging to these particles are not strained out. They remain in the milk and under favorable temperatures thrive and multiply unless arrested.