CREAMING MILK AT THE FARM. 67 



In addition to the forces which cause creaming of 

 milk, other factors influence the completeness of the 

 separation. Chief of these are, the viscosity of the 

 milk, currents in gravity methods, the length of time 

 during which the milk is subject to creaming force, 

 the size of the fat globules in the milk, the temperature 

 of the milk during the separation, the volume of the 

 milk subjected to the action of the creaming forces 

 and the special construction of the pan, can, or 

 machine in which the creaming takes place. 



Briefly, these factors influence creaming as follows : 

 The more viscous or sticky the milk, the more difficult 

 it is to cream. Currents in gravity creaming should 

 be of short duration. This is accomplished by cool- 

 ing all the milk in a pan or can to a uniformly low 

 temperature, as rapidly as possible. 



The longer the time during which milk is subjected 

 to creaming forces, the more completely is the cream 

 separated, although there is a limit to the time which 

 may be used economically. 



The larger the size of the fat globules in the milk, 

 the more easily and completely may the cream be 

 extracted. 



The warmer the milk, up to at least 1 60 degrees for 

 the centrifuge, unless it be fresh from the cow, the more 

 favorable are the conditions for creaming ; but, in the 

 case of gravity creaming, where separation takes place 

 somewhat slowly, it is necessary in practice to cool 

 the milk in order to prevent souring. So far as the 

 creaming of milk is concerned, a higher temperature 

 is more favorable, chiefly because the milk is less 

 viscous. 



