
New York AcriconTuraL Experiment Sration, 2255 
understood. The formation of lactic acid in cheese-making is 
doubtless produced by the lactic acid bacteria and not by the 
rennet-ferment. 
Process oF MANUFACTURING CHEESE. 
General outline. The process of manufacturing cheese is, im 
brief outline, as follows: The casein of the milk is coagulated by 
the action of rennet. The coagulated casein or curd, which is at 
first soft and full of moisture, is cut into small pieces and allowed 
to stand at a certain temperature until the curd becomes tough 
and less moist. The whey is then removed, and the curd, after 
draining sufficiently, is mixed with salt, then put into molds and 
subjected to a gradual pressure. After being in press several 
hours the cheese is placed in a room of even, moderate tempera- 
ture, when it undergoes certain changes, acquiring, in time, the 
flavor and other well-known properties of cheese. 
The general principle underlying: the manufacture of cheese 
depends, primarily, upon the action of rennet on milk. While 
the theory of cheese-making depends upon this easily stated prin- ° 
ciple, and while the actual process might, from the foregoing 
outline, appear extremely simple, the manufacture of cheese is, in 

ik 
reality, a complicated process in its details, and requires, for — 
highest success, rare skill and trained judgment. In order to 
present some of the difficulties encountered in cheese-making, we 
will consider the process more in detail. 
SomsE DETAILS OF CHEESE-MAKING. 
(1.) Treatment of milk before adding the rennet—In making 
cheese, the milk is gradually heated to a temperature of about 
85° F., a slightly higher or lower temperature being used accord- 
ing to the judgment of the maker, as peculiar conditions may 
demand, The heating of the milk is accompanied by careful 
stirring, in order to enable the milk to heat uniformly and also to 
keep the fat evenly distributed through the milk. The milk is 
held at about 85° F. until a very slight amount of acid has been 
developed, usually known as “ripening ;” this ripening may be 
hastened by the addition of a small quantity of sour milk. In 
the experiments described in this report, John Boyd’s “starter” 
was used. The exact degree of ripeness is difficult to deter- 
ip. 29 
