MILK AND ITS PRODUCTS 



179 



The former can therefore be churned in the same length 

 of time at a lower temperature than the latter. 



The ideal richness is about 30%. A cream much richer 

 than this will stick to the sides of the churn, which re- 

 duces the amount of concussion. The addition of water 

 to the churn will overcome this stickiness and cause the 

 butter to come in a reasonable length of time. It is bet- 

 ter, however, to avoid an excessive richness when a ex- 

 haustive churning is to be expected. 



5. Amount of Cream in Churn. The best and quick- 

 est churning is secured when the churn is 

 one-third full. With more or less cream 

 than this, the amount of concussion is re- 

 duced and the length of time in churning 

 correspondingly increased. 



6. Speed of Churn. The speed of the 

 churn should be such as to produce the great- 

 est possible agitation or concussion of the 

 cream. Too high or too low a speed reduces 

 the amount of concussion. The proper speed 

 for each particular churn must be determined 

 by experiment. 



7. Abnormal Fermentations. The slimy 

 or ropy fermentation sometimes causes trouble 



. in churning by rendering the cream exces- 

 sively viscous. Cream from single herds may 

 become so viscous as to render churning im- 

 possible. 



Dairy Thermometer. One of the essen- 

 tials in making good butter is a thermometer 

 *Dairy' like that shown in Fig. 49. It is necessary to 



Thermom- ,1,1 r , 1 



eter. watch the temperature of the cream dur- 



ing ripening, and to secure uniform and exhaustive 



