Gravity Processes of Creaming. 101 



increase the amount of solids not fat, we should ex- 

 pect such milk to be more easily creamed, but the 

 favorable effect of the increase of solids is more 

 than counterbalanced by the unfavorable effect of 

 the character of the solids. Of the solids not fat, 

 albumin, casein, sugar and ash increase the viscos- 

 ity of the milk in the order named, and of these 

 the casein is more subject to variation, so that the 

 increase in the proportion of solids not fat ordi- 

 narily means an increase in casein, and this means 

 a largely increased viscosity. And the increase in 

 viscosity tends to prevent the separation of the fat 

 more than the increase in specific gravity tends to 

 aid it. In general, the conditions which bring about 

 an increase in the viscosity of the milk occur at the 

 same time as the fat globules are growing smaller, so 

 that we find a wide range of variability in the ease 

 and completeness with which cream may be separated 

 by gravity process. 



Shallow pan crea7ning .—This is the oldest method 

 of separating cream from milk, and notwithstanding 

 the rapid changes that have taken place in cream- 

 ing methods since the introduction of centrifugal 

 separators, large amounts of butter are still made 

 from cream separated in this way. The conditions 

 most favorable for a complete separation of the fat 

 in the shallow pan system are, that the milk should 

 be put at rest in the pans as quickly as possible 

 after it is drawn, that it should cool with a fair de- 

 gree of rapidity to a temperature of 60° F., and that 

 it should remain as nearly as may be constantly at 



