ACTUAL OVERRUN 127a 



The amount of overrun is directly dependent upon the 

 following factors: 



Efficiency of skimming and churning. 

 Composition of the butter. 

 Richness of milk and cream. 

 Mechanical losses. 

 Correct reading of tests. 



Efficiency of Skimming and Churning. It is evi- 

 dent that the more fat there is lost in skimming and 

 churning the lower will be the overrun. To obtain a 

 maximum overrun, the loss of fat as shown by the Bab- 

 cock test should not exceed 0.05 per cent for skim-milk 

 and 0.15 per cent for buttermilk. 



In this connection it should be stated that during the 

 summer season it is not at all uncommon to find butter- 

 milk testing from 0.3 to 0.5 per cent, largely a result of 

 employing too high a churning temperature. 



Composition of the Butter. Besides butter fat, butter 

 contains water, curd and salt, and, other conditions the 

 same, the greater the amount of non-fatty matter in 

 butter the greater the overrun. Water, being present in 

 large quantity and subject to considerable variation, very 

 appreciably affects the percentage of overrun. There has 

 been a tendency among creameries the past few years 

 to manipulate butter so as to increase its normal water 

 content and thereby increase the overrun. 



The water in butter easily fluctuates between 10 and 

 15 per cent, and a good overrun can be obtained by keep- 

 ing it within the limits of 13 and 14 per cent. 



Salt as a rule has little influence on the per cent of 

 overrun because under normal conditions an increase in 



