Bacteria and Butter Making. 139 



The intensity of flavor of butter is, in a general way, 

 directly related to the amount of acid that is formed in 

 the cream. A low acidity at time of churning is usually 

 associated with a mild flavor, while a higher degree of 

 acidity, up to a certain point, imparts a more pro- 

 nounced flavor to the product. If cream is over-ripened, 

 the quality of the flavor is seriously impaired. 



In determining the acidity of cream, a definite volume 

 is taken, and the acidity determined by titration, express- 

 ing the results as such a per cent of lactic acid. Mani- 

 festly, the amount of fat in the cream influences the ap- 

 parent per cent of acidity. The acidity will not usually 

 exceed 0.5 to 0.7 per cent, but in reality the serum will 

 contain more than this, as the acid is formed in the 

 serum, the butter fat having no role whatever. In a 

 very rich cream, 40 to 50 per cent fat, it is impossible to 

 develop more than 0.4 to 0.5 per cent of acidity, and the 

 flavor of the butter will be low, because of the relation 

 between the amount of acid and fat, while in a thin 

 cream having the same acidity, the ratio between the 

 amounts of fat and acid will be very different. For ex- 

 ample, in one hundred pounds of 50 per cent cream of 

 0.5 per cent acidity there will be one-half pound of acid 

 and fifty pounds of fat; in the same quantity of cream 

 containing 20 per cent of fat and having an acidity of 

 0.5 per cent there will be one-half pound of acid to 

 twenty pounds of fat. The flavor of the butter from the 

 rich cream will be quite different in intensity from that 

 made from the thinner cream. 



The* acidity of cream cannot be determined with any 

 degree of accuracy by the taste or odor. Every butter 

 maker should have some method of determining the de- 

 gree of acidity in his cream, so that he 'may better con- 



