THE CHEMISTRY OF BUTTER MAKING 63 



ness of cream, (2} temperature of the cream, and 

 (8) individuality of the cream as affected by period 

 of lactation, season of the year, nature of the fat, 

 and breed characteristics. 



Ripe cream, containing .5 of a per cent of acid, 

 usually churns more completely than unripe cream. 

 It is believed that this is due to the acid coagulating 

 the casein of the cream serum, thereby reducing the 

 surface tension of the fat globules. The ripeness of 

 the cream is one of the most important factors in 

 churning. If creams of different degrees of ripeness 

 are combined and churned, there is an unevenness in 

 the butter product due to the mixed cream not churn- 

 ing evenly, a part producing butter granules be- 

 fore the rest of the cream has comijleted the process 

 of churning. If overripe, a poor quality of butter 

 is produced, due to the presence of excessive amounts 

 of fermentation products. It was formerly believed 

 that an excessive amount of lactic acid caused a loss 

 of butter fat in churning. It has been found, how- 

 ever, that lactic acid has no solvent action upon 

 butter fat. It should be the object to secure the 

 same degree of acidity for each cliurning, so as to pro- 

 duce as even a product as possible. If cream is not 

 sufficiently ripened, butter of poor keeping quality is 

 produced, the fermentation changes which take place 

 in the butter causing it to have undesirable flavors. 

 One of the objects of the thorough ripening of cream 

 is to prevent further and undesirable fermentation 

 processes from taking place later in the butter. 



