CHAPTER VII 

 THE CHEMISTRY OF BUTTER MAKING 



65. Churning. — When cream is agitated, the fat 

 globules coalesce, forming granules of butter. Vari- 

 ous theories have been advanced to explain the 

 changes which take place during the process of 

 churning. It is believed, however, that the change 

 is largely physical in character and that the agitation 

 of churning is necessary in order to overcome the 

 resistance offered by the serum of the milk. During 

 the process of churning, the globules lose their 

 spherical form and become irregular masses of fat. 

 These irregular masses more readily coalesce than 

 spherical bodies. Various forms of churns have 

 been devised to carry out different theories as to 

 churning. Some churns have Wen provided with 

 paddles and special devices for agitating the cream 

 and for rupturing the membrane in which the milk 

 fat globules were supposed to be inclosed. With 

 change of views in regard to theories of churning, 

 most of these devices have been discarded, and our 

 present churns are much simpler in construction and 

 do not have special devices for agitating the cream, 

 this being secured largely by the concussion during 

 the churning process. 



The conditions influencing churning are (1) ripe- 

 62 



