. Milk. Milk. 164 MILK If the temperature is too low the bottles should be placed in a water-bath of 140° F. for some minutes before reading is taken. Sammis states that reading between 110° and 150° F. gives prac- tically the same results, the difference owing to expansion with increasing temperature being neghgable. In cream testing the temperature must be controlled more accurately. The mixture of milk and acid need not be centrifuged immedi- ately after mixing, but will give accurate results if kept for some time. However, when not centrifuged immediately after mixing the fluid must be war
. Milk. Milk. 164 MILK If the temperature is too low the bottles should be placed in a water-bath of 140° F. for some minutes before reading is taken. Sammis states that reading between 110° and 150° F. gives prac- tically the same results, the difference owing to expansion with increasing temperature being neghgable. In cream testing the temperature must be controlled more accurately. The mixture of milk and acid need not be centrifuged immedi- ately after mixing, but will give accurate results if kept for some time. However, when not centrifuged immediately after mixing the fluid must be warmed in a water-bath at 71° C. (160° F.). The test bottles must be washed after each test is finished before the fat solidifies. The contents, while still warm, may be emptied into a waste jar (Fig. 57). A solution of potassium bichromate 60 parts, in water 300 parts and concentrated sulphuric acid 460 parts or a strong alkaU or soda solution can be used after the bottles have been rinsed in hot water. A little ether will faciUtate the solu- tion of lumps of fat adhering to the glass. A tube brush is often necessary to clean out the neck. Special bottle holders have been de- Fig. 57.—Waste vised by means of which a number of bottles jar for Babcock test can be washed at the same time, and by in- 202, Agri. Exp. Sta. verting the holder the water can be drained out of dolo, Agri. Coll.) of the bottles. A bottle holder suitable for this work is illustrated in Fig. 58. There are some devices which facilitate the work when a large number of tests are made. The acid can be run into the test bottles from a large container which has a buret attached (Fig. 59). An- other style has a side tube attached which is just large enough to hold the requisite amount of acid when filled (Fig. 60). Finally, a dipper has been constructed which holds of sulphuric acid (Fig. 61). Other devices aim to facihtate the adding of hot water. One style of centrifuge has a water container attac
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Keywords: ., bookauthorheineman, bookcentury1900, bookdecade1910, bookyear1919
