CHAPTER VIII. 



CHUBXIXG. 



The process of causing the particles of butter fat 

 to unite into masses, so that they may readily be 

 separated from the milk serum, is called churning. 

 Such union of the particles of fat is ordinarily 

 brought about by agitation of the cream in a suit- 

 able vessel, called a churn. If milk or cream be 

 agitated at a temperature somewhat below the melt- 

 ing point of butter fat, the particles of fat, as they 

 pass by one another, agglutinate themselves into 

 masses, and, the process being continued, the fii-st 

 formed masses continue uniting, until finally the 

 whole body of fat may be brought together in a prac- 

 tically solid mass. The conditions influencing the 

 separation of fat in this way are, first, the viscosity 

 of the milk ; second, the ripeness of the cream ; 

 third, the temperature; fourth, the nature of the 

 agitation; fifth, the quality of the globules of fat. 



The viscosity of the 7)iiU\ — The viscosity of the 

 milk affects the churning, in that it tends to keep 

 the particles of fat from moving freely upon one 

 another, and in that the viscous portions of the 

 milk, notably some of the albuminous matter, form a 

 more or less dense layer about the fat globules. 



(140) 



