64 QUESTIONS AND ANSWERS 



Can butter be tested for fat by the Babcock method? 

 Yes; but not with as much accuracy as many 

 other dairy products. 



How is butter tested for its fat content? 



1. By the ether method. Evaporate a known 

 weight (2 to 3 grams) to dryness in a flat-bottom 

 dish. Then wash the total contents of the dish 

 upon a weighed filter paper, using about 50 c. c. of 

 ether or naphtha. Then wash free from fat the 

 residue on the filter paper with ether or naphtha. 

 The filter is then dried at 100° C. to constant weight 

 and weighed. The percentage fat is determined by 

 the difference between the weight of butter and the 

 weight of fat. 



2. By Babcock test. Weigh 4 grams of butter 

 into a cream bottle, adding enough water to make 

 18 grams in the bottle. Add 17.5 c. c. of sulphuric 

 acid and after thoroughly mixing whirl in the cen- 

 trifuge for five minutes. Add hot water at 200° F. 

 to raise the fat in the graduated neck of the bottle. 

 Whirl again for two minutes, then multiply the 

 reading on the bottle by 4.5. 



How should the scale be read in testing butter? 



The same as in testing cream, giving credit for 

 that part of the scale between the bottom of the 

 fat column and the bottom of the meniscus. The 

 temperature of the fat should be between 130° and 

 140° F. 



What is meant by an aliquot part of a quantity? 



It is the part that results from dividing a quan- 

 tity by a whole number, which leaves no remainder. 



