250 



MANUAL OF MILK PRODUCTS 



CHURNING 



(See Fig. 49 and Plate XIV) 



Churning is the process of separating the butter-fat from the 

 other constituents in the cream. This is brought about by 

 subjecting the cream to violent agitation in such a way that the 

 butter-fat globules are brought together and cohere as a result 

 of concussion. This gathering together of the fat globules into 



butter granules 

 is influenced by 

 a number of fac- 

 tors, including 

 the richness of 

 the cream, the 

 temperature, the 

 ripeness of the 

 cream, the vis- 

 cosity of the 

 cream, the 

 amount of cream 

 in the churn, the 

 nature of the agi- 

 tation, the size 

 and quality of 

 the fat globules. 

 Richness of the cream: 



The fat globules exist in the cream in enormous numbers, 

 and the richer the cream, the more closely the fat globules come 

 into contact with each other. For this reason, rich cream churns 

 more easily than thin cream, other things being equal. It, 

 however, should not be so rich as to adhere to the sides of the 

 churn and prevent its receiving the proper amount of agitation 

 as the churn is revolved. Under ordinary conditions cream con- 



Fig. 49. — Simplex churn and butter-worker. 



