THEORETICAL OVhRRUN 129 



2. To calculate the amount of buttermilk per 100 

 pounds of milk. 



Rule: This is approximately found by increasing the 

 pounds of butter fat in the cream by one-sixth and sub- 

 tracting the result -from the total pounds of cream. 



Example : How much buttermilk from 100 pounds of 

 4% milk yielding 10 pounds of cream testing 40% ? 



10 X .40 = 4.0 Ibs. of butter fat. 

 4X11/6 = 4.66, 10 4.66 = 5.34= No. Ibs. 

 buttermilk. 



OVERRUN. The method of calculating the actual over- 

 run at creameries has already been discussed in Chapter 

 XL With the following known conditions the theoretical 

 overrun can be calculated with a fair degree of accuracy : 



(1) Average per cent of fat in butter. 



(2) Loss of fat in skim-milk. 



(3) Loss of fat in buttermilk. 



Problem : 100 pounds of milk testing 4% yields cream 

 testing 40%. Test of skim-milk is .05%, that of butter- 

 milk .15%. Per cent of fat in butter is 84. Calculate 

 butter and overrun. 



By applying the rules for calculating skim-milk and 

 buttermilk we find that there will be 90 pounds of skim- 

 milk and 5.34 pounds buttermilk. 



. 90 X .05 = .045 = lb . fat in skim-milk. 

 .0534 X .15 = . 008= lb. fat in buttermilk. 



Total loss = .053 



4 .053= 3,947 = fat made into butter. 

 3.947 .-r- .84= 4.70 =lbs. butter made. 



4.70 4= .70 = overrun in Ibs. 

 7-5-4X 100=17.5 = overrun in per cent. 

 9 



