104 THE BOOK OF BUTTER 



were more organisms left in the cream of the vat method, 

 as reported by Hammer,' for tlie number of bacteria in 

 cream is not an exact nor a constant measure of the flavor 

 of butter. Mortensen, Gacssler, and Cooper ^ also found 

 that more fat was lost in the buttermilk from the vat 

 method than from the continuous system of pasteurization. 



Pasteurization of cream for the manufacture of butter 

 may be conducted in a different way from handling milk 

 and cream for consumption as such, because in the latter 

 case it is desirable that there may be as little physical 

 and chemical change as possible. This can be accom- 

 plished at the lower pasteurizing temperatures for a 

 longer period, as in the vat method. However, in the 

 manufacture of butter, the higher temperatures of the 

 continuous method may be used very satisfactorily. In 

 the average creamery where the deliveries of cream are not 

 regular, the vat method is more convenient than the 

 continuous system. Inasmuch as a ripening vat must be 

 used regardless of the particular method, the initial invest- 

 ment for the vat pasteurizer is less than the cost of the 

 continuous pasteurizer plus the cream ripener. 



75. Notes. — In operating a pasteurizer many per- 

 plexing problems arise ; such as, proper speed, sour cream, 

 and thin cream. 



Speed. — Farrell ^ advises that in operating a continuous 

 pasteurizer speed is important in many machines, for it 



1 Hammer, B. W., The Pasteiirization of Cream for Butter- 

 making, Agri. Exp. Sta. Iowa State Col., Bui. 156, 2d part, p. 35, 

 1914. 



2 Mortensen, M., Gaessler, W. G., and Cooper, W. H., The 

 Pasteurization of Cream for Buttermaking, Agri. Exp. Sta. 

 Iowa State Col., Bui. 156, 1st part, p. 15, 1914. 



' Farrell, John J., Pasteurization of Cream for Butterm^aking, 

 Albert Lea State Cry., Bui. 63, pp. 6-9, 1916. 



