170 MANAGEMENT OF DAIRY PLANTS 



value of the butter, and g the per cent of overrun obtained, 

 then 



y = dx— ^ 



lOO+g 



z = dX-^ 



lOO 



Example: The overrun is 20 per cent on butter sold for 30 

 cents per pound; determine the value of the overrun per pound 

 of butter and per pound of butter fat. 



y = 30 X 20/120 = 5 cents, 

 z = 30 X 20/100 = 6 cents. 

 Tables Nos. VIII and IX illustrate the effect which the in- 

 crease or decrease of per cent of overrun and the market value 

 of the butter have on the value of the overrun per pound of 

 butter and per pound of butter fat. 



RELATION BETWEEN CHEMICAL COMPOSITION 

 OF BUTTER AND OVERRUN 



Composition of Butter. — The composition of normal Ameri- 

 can butter in accordance with the analysis made by the De- 

 partment of Agriculture,! Washington, D. C, of 695 samples 

 is as follows: 



Per cent 



Fat 82.41 



Moisture 13 ■ 9° 



Salt 2.51 



Curd 1. 18 



Total 100 . 00 



Butter Fat Content of Butter. — The butter fat is the 

 principal ingredient both in regard to amount and to its com- 

 mercial value. An increase in fat content of butter means a 

 corresponding decrease in butter overrun and vice versa. An 

 increase in fat content of the butter increases the cost of the 

 butter to the manufacturer. 



■ Bui. I4g, B. A. I. 



