CREAMERY BUTTER MAKING 211 



tance at present than the pasteurization of hand separator 

 or gathered cream. Heretofore the apparent difficulty in 

 the way of pasteurizing this cream has been the high 

 degree of acidity which it often reaches before delivery 

 to the creamery. 



To arrive at some definite conclusions, a series of ex- 

 periments was carried out at the Michigan Dairy School 

 under the direction of the author, in which cream with 

 an acidity varying from .3 to .6 per cent was pasteurized 

 in a continuous pasteurizer at a temperature of 185 F. 

 After pasteurization, one-half was left without starter, the 

 other half was treated with 25 per cent starter after it 

 had reached a temperature of 65 F. Both lots were 

 then cooled to 48 F., where they were held for ten 

 hours and then churned. Control experiments were car- 

 ried of unpasteurized cream ripened without starter. 

 Samples of the butter made were sent to W. H. Healy of 

 New York for scoring. 



The results obtained in these experiments are sum- 

 marized as follows : 



1. Cream with a fat content of from 20 to 40 per 

 cent can be pasteurized without difficulty even when the 

 acidity reaches .6 per cent. 



2. When no starter was added to the pasteurized sour 

 cream no improvement in the flavor of the butter was 

 noticeable. 



3. When the pasteurized sour cream was treated with 

 25 per cent starter the flavor of the butter was improved 

 from 2 to 4 points in every experiment. 



4. Pasteurizing sour cream destroys its heavy con- 

 sistency, which cannot be recovered even when ripened 

 with 25 per cent starter. The body of the butter from 

 this cream was perfect, however. 



