276 MARKET DAIRYING 
the amount of salt usually results in a decrease in the 
amount of water. Of course, where special methods of 
manipulating the water content are resorted to, it is 
possible to increase the overrun by increasing the amount 
of salt. 
Curd is present in butter in very small quantities, and 
its influence on the overrun is very slight. 
Richness of Milk and Cream. The test of skim-milk 
is practically independent of the richness of the milk— 
that is, other conditions the same, skim-milk from 2.5% 
milk will test the same as that from 5 per cent milk. But 
since it takes twice as much 2.5 per cent milk to obtain 
100 pounds of butter fat as is required with 5 per cent 
milk, it follows that the loss of fat in the skim-milk will 
be twice as great with the poorer milk. 
Assuming a loss of 0.05 per cent fat in the skim-milk, 
the loss of fat in the amount of milk needed to yield 100 
pounds of butter fat is one pound greater for the poorer 
milk. The extra pound of fat thus lost would have made 
approximately 1.18 pounds of butter, so that the overrun 
from a 5 per cent milk may be expected to be approxi- 
mately 1.18 per cent greater than that from milk testing 
2.5 per cent. : 
Rich cream yields a higher overrun than poor cream 
because of the smaller loss of fat in the buttermilk. That 
is, there is less buttermilk from rich cream than poor 
cream, and, since the per cent of butter fat in the butter- 
milk will be about the same in both cases, it follows that 
the loss will be greater from the poor cream, which 
yields the greater amount of buttermilk. 
Assuming a loss of 0.2 per cent of fat in the butter- 
milk, 100 pounds of butter fat in 35 per cent cream will 
