CREAM RIPENING 121 



perature. Ordinarily it is safer to ripen cream at 60°- 

 65° F. than at the higher temperatures. 



WHEN CREAM IS RIPE 



Cream is ripe when the desirable amount of acid has 

 been developed. This will depend on the requirement 

 of the market. 



90. Uniform ripening. — To obtain uniform ripening 

 and really to determine when cream is ripe, it is necessary 

 to allow the production of a certain acidity in the serum 

 of the cream. For example, .4 per cent acidity in cream 

 testing 30 per cent milk-fat is not the same as .4 per cent 

 acidity in cream with a fat-content of 40 per cent, for the 

 serum which contains the acid is not present in the same 

 proportion in both creams. 



The following method may be used to determine the 

 desired acidity : (100 per cent — per cent fat) X arbitrary 

 factor = desired acidity. This problem should be worked 

 as follows : 100 per cent — 30 per cent milk-fat = 70 

 per cent serum. 70 per cent X .006 (arbitrary factor) = 

 .42 per cent acidity that is desired ; 100 per cent — 40 

 per cent milk-fat = 60 per cent serum ; 60 per cent X 

 .006 (arbitrary factor) = .36 per cent acidity that is 

 desired. Thus it is seen that .42 per cent acidity in cream 

 testing 30 per cent milk-fat is the same degree of ripeness 

 as .36 per cent acidity in cream testing 40 per cent milk- 

 fat. The cream should be ripened until it contains very 

 nearly the proper amount of acid. In case a high acidity 

 is required, such as .6 or .65 per cent, great care should 

 be observed, for over-ripening is likely to take place. 



91. How to ascertain and satisfy the demand of the 

 trade. — It should be understood that the arbitrary fac- 

 tor is determined by learning the demand of the trade. 



