Ko. 4.] MILK AND CREAM. 359 



Methods of Separating Cream. 



The three methods of separating cream from the milk may 

 be defined as (lie shallow pan, deep setting, and separator 

 systems. 



The quantity of cream for consumption is not seriously 

 affected by cither of these methods of separation, so that 

 relative economy depends upon the completeness and cost of 

 separation. 



In the separation of cream by force of gravity, there is a 

 meat loss of fat, and a longer time required, than when the 

 centrifugal process is employed. According to Wing, the 

 conditions of the milk that affect the creaming by the gravity 

 process are first, the size of the fat globules ; second, the 

 amount of solids not fat in the milk ; third, the character of 

 the solids not fat ; and fourth, the temperature of the milk. 



The larger the fat globules, the more rapidly they separate 

 from the milk. The size of the globules is dependent upon 

 the breed and individuality of the cow, and upon the period 

 of lactation. The amount of solids not fat affects the rising 

 of the cream, because of the difference in specific gravity 

 between the fat and the other ingredients. Solids not fat 

 are heavier than water, and hence, the larger the amount of 

 solids not fat, the more rapid one would expect the separa- 

 tion. The favorable effects of the solids not fat are, as a 

 rule, however, more than offset by the character of the solids. 

 The solids not fat are the casein, albumin, sugar and ash, 

 and these in the order enumerated increase the viscosity of 

 the milk. This increase in viscosity retards the separation 

 of the fat to a greater degree than the increase in specific 

 gravity tends to aid it. This increase in solids and viscosity 

 takes place as the size of the fat globules are growing smaller, 

 hence cows in an advanced stage of lactation produce milk 

 which separates very slowly. Finally, a sudden chilling 

 of the milk immediately after milking and keeping it at a 

 temperature of 40° F. aids in a thorough separation of the 

 cream . 



Shallow Setting. — This old method has long been dis- 

 carded by those who understand modern dairy principles. 

 Its chief objectiou is its inconvenience, and the difficulty of 



