152 CRIlAMIiRY BUTTER MAKING 



of fat in the buttermilk. High temperatures are less lia])le 

 to produce this result than relatively low. Cream of this 

 kind should be pasteurized at not lower than 185° F. 

 The coagulation of the casein interferes with the cooling 

 and straining of the cream, and it has been shown that 

 the high loss of fat in the buttermilk is at least partly 

 due to the fat globules which are enclosed in the curd 

 particles. 



In general, pasteurized cream must be churned at a 

 lower temperature than unpasteurized to get exhaustive 

 churnings. Where cream has been heated it is also neces- 

 sary to keep it at a low temperature longer before churn- 

 ing than unheated cream, because of the slowness with 

 which the fat becomes thoroughly chilled. 



The acidity of cream is somewhat diminished by the 

 pasteurizing process. This process also diminishes the 

 heavy consistency of sour cream, which it does not seem 

 to recover even when ripened with a heavy starter. This, 

 however, has no effect on the quality of butter. 



To obtain good results from pasteurizing sour cream it 

 is absolutely essential to treat the pasteurized product with 

 a heavy starter even if the latter shows an acidity of 

 0.6% or more. 



Cost of Pasteurizing Cream. According to Danish 

 experiments the cost of pasteurizing cream is approxi- 

 mately .1 cent per pound of butter. These results seem 

 to be confirmed by the best practical butter makers in 

 this country who have pasteurized for several years. 



The cost of pasteurizing must, however, always depend 

 largely upon the manner in which the pasteurizing proc- 

 ess is carried out. For example, if the water used for 

 cooling the cream is pumped into the water supply tank 



