DAIRY LABORATORY MANUAL 

 AND NOTE BOOK 



DAIRY RULES. 



1. Rule for determining the number of pounds of butterfat in a given 

 amount of cream or milk when the percentage of fat is given. 



Multiply the percentage of butterfat by the pounds of milk and divide 

 by 100 (i.e., point off two places). 



2. Rale for determining the percentage of casein in milk when the per- 

 centage of fat is known. (Van Slyke.) 



Subtract 3 from the percentage of fat in milk, multiply the remainder 

 by .4 and add 2.1 to the result. 



Milk with 4.8 per cent fat has 2.82 per cent casein [(4.8 — 3) x.4+2.1 = 

 2.82]. 



3. Rule for determining the price per pound received for butterfat in 

 cream when the percentage of fat and the price per gallon are given. 



Multiply the pounds of cream in a gallon by the percentage of fat given 

 (point off two places). This will give the pounds of fat one gallon of cream 

 contains. Divide the number representing the price per gallon of cream by 

 the number of pounds of butterfat, the quotient will equal the price per pound 

 of butterfat. 



4. Rule for determining the price of a gallon of cream when it is being 

 paid for on the butterfat basis. 



Multiply the percentage of fat in the cream by the pounds of cream in 

 a gallon (poin,t off two places) . This will give the number of pounds of fat 

 in a gallon. Multiply this by the price per pound paid for fat. 



5. Rules for finding the percentage of solids not fat. 



Rule A . — (A rough practical rule.) The (Quevenne) lactometer reading 

 plus the percentage of fat divided by 4 equals the solids not fat. 



Rule B. — (Accurate rule, recommended for accurate work.) 



One fourth of the (Quevenne) lactometer reading plus .2 times the fat 

 equals the solids not fat. 



If the lactometer reading is 31 and the fat is 3.8 per cent the solids not 

 fat equal 8.51 per cent. (31 + 4+ .2X3.8 = 8.51.) 



