294 CHURNING 



sents the type of churns now almost exclusively in use in this 

 country. Some of these churns have a swinging motion, but 

 the majority are revolving or rotating barrels or boxes. From 

 the point of view of efficiency of agitation the hollow barrel 

 or box churn is the most desirable. The rotating motion of 

 the churn causes the fat globules to strike the sides of the churn 

 and the concussion thus produced hastens the formation of the 

 butter granules. The churns of small capacity such as are used 

 on the farm are usually, though not necessarily, entirely hollow, 



rig 1 . 47. Giant Dibrow churn 

 Courtesy Davis-Watkins Dairymen's Mfg. Co. 



turning end over end, while the great majority of the factory 

 churns are equipped in their interior with rollers and workers, 

 and with shelves attached to the sides of the churn, raising the 

 butter and dropping it on the rollers at least once with every 

 revolution of the churn. 



Speed of Churn. Aside from the style or construction of 

 churn, the amount of agitation and concussion materially de- 

 pends on the speed of the churn. The speed which produces 

 the maximum agitation and at which the churning is completed 

 in 'the shortest time is that which will subject the particles 

 of cream to the most rapid fnotion upon one another. Up to a 

 certain point an increase in the speed of the churn increases 

 the concussion of the particles of the cream. But when the 

 speed is carried to the point where the centrifugal force causes 

 the cream to partake of the motion of the churn, the motion of 

 the particles of cream upon one-another is diminished, the con- 



