THE CONSTITUTION OF MILK. 9 
Cheese for the home market contains 36 to 37 per cent and 
export cheese 33 to 36 per cent of water. 
15. Whey. 
In the manufacture of cheese, the milk is curdled by ren- 
net, and the curd cut into small pieces from which the hquid 
portion, or whey, is expelled. It consists of the major part of 
the water of the milk, which carries with it nearly all the 
soluble components, viz., the albumen, milk sugar, ash, and 
also a small portion of fat, as the globules break away from 
the surface of the curd when it is cut. 
16. Composition of Whey. 
The average composition of whey for an entire season in 
an American cheese factory is as follows: Water 93.12 per 
cent, total solids 6.88 per cent, fat .27 per cent, nitrogenous sub- 
stances .81 per cent, sugar, ash, etc., 5.80 per cent. 
17. Losses of Fat in Whey. 
At the Minnesota Experiment Station in 1892 cheese was 
made from normal milk of different fat contents. The follow- 
ing table shows the losses of fat from these different milks: 
LOSSES OF FAT IN MILK OF DIFFERENT FAT CONTENTS. 
Per cent fat in milk____-_--_--_- 3.5 to 4 | 4104.4 | 45to5 | 5to5.5 
Per cent fat in whey_-------_--_ .38 .36 39 32 
Number of trials___--___--------- 28 | 31 14 4 
In another series of experiments where cream was added 
to milk to make it test 6 per cent, the loss of fat in the whey 
was no greater than in the whey from normal milk similar to 
that to which the cream was added. 
In all cases the richer milk made more cheese, which 
would of course leave less whey from each 100 pounds of milk. 
It is easily seen from this that the fat in rich milk can be worked 
into cheese more economically than the fat in poor milk. 
What effect could this have in applying the second rule given 
in paragraph 11? 
