MILK SUGAR AND LACTIC ACID 49 



the pink color, then the sample of cream contains .4 

 per cent lactic acid. 



55. Acidity of Cream. Cream that is suitably 

 ripened for churning should contain about .5 of a 

 per cent of lactic acid. If the cream contains more 

 than .6 per cent of acid, it is liable to cause coagula- 

 tion of the casein and formation of clots in the cream, 

 and when churned, mottled butter is produced. The 

 acid test will be found valuable in butter making 

 as a means of producing a uniform product, which 

 is accomplished by having the cream each day of the 

 same degree of ripeness, and churning under uniform 

 conditions. Any of the methods described for deter- 

 mining the acidity of cream will be found helpful 

 in producing a uniform butter product. 



