RECEIVING SAMPLING, AND GRADING. 89 



thoroughly. The remedy is to use more acid, or to warm milk 

 and acid before mixing, or to shake the mixture thoroughly 

 before whirling. (3) Occasionally there is a layer of impure 

 foam at the top of the fat column. This is generally due 



FIG. 46. The oil-test churn. 



to the use of hard and impure water. The remedy is to use 

 pure distilled hot water. For more detailed information on 

 this subject see "Testing Milk and its Products/' by Farrington 

 and Woll. 



Necessity of Good Milk. All authorities agree that the best 

 grade of butter and cheese cannot be made from sour or tainted 

 milk. The two countries renowned for the excellence of their 



