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 malting 

 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. 



