1872 



The Cornell Reading-Courses 



Fig. 78. — The shalloiv-pati method 



weight of matter. Skimmed milk is attracted to the earth with greater 

 force than milk-fat because it is heavier. The lighter substance, cream, 



is crowded away from the earth, or to the 

 surface of the vessel that contains whole 

 milk. In ordinary phraseolog}^, there- 

 fore, cream "rises." 



There are three methods of cream 

 separation depending on the force of 

 gravity. They are the shallow-pan 

 method, the deep-setting method, and the water-dilution method. In the 

 first method, the cream is skimmed off with a 

 shallow dipper, and in the other two methods 

 the skimmed milk is drawn oft" leaving the 

 cream. These gravity methods, however, have 

 distinct disadvantages, one of the most im- 

 portant of these disadvantages being the loss 

 of a small amount of milk -fat each time they 

 are used. Tests of the relative merits of the 

 gravity methods of separation have been made 

 in order to deteiTnine how great this loss is. 



According to experiments made by Hun- 

 ziker,^ the percentage of milk-fat in the 

 skimmed milk separated from cream by these 

 gravity methods of cream separation is as follows: water-dilution method, 



.68 of I percent of fat; shallow-pan 

 method, .44 of i per cent of fat; 

 deep-setting method, .17 of i per cent 

 of fat. 



This loss of milk-fat from the milk 

 of a single cow giving 5000 pounds of 

 milk each year, is shown in Figure 81. 

 The skimmed milk usually amounts to 

 about eighty-five per cent of the whole 

 milk, which in this case would mean 

 eighty-five per cent of 5000 pounds of 

 whole milk, or 4250 pounds of skimmed 

 milk. In the manufacture of butter 

 certain amounts of moisture, salt, and 

 casein are incorporated. Thus it is 

 possible to make more butter from a 

 certain amovmt of milk-fat than there was original fat. This in- 



FiG. 79. — The deep-setting 

 method 





I 

 ' 1 



Fig. 80. — The water -dilution method 



• The hand separator and the gravity systems of creaming. 

 Agricultural Experiment Station. Bulletin ii6. 



By O. F. Hunziker. Purdue University 



