4 BULLETIN 576, U. S. DEPARTMENT OF AGRICULTURE 
CUTTING AND HEATING THE CURD 
The best time to cut the curd is shortly after it shows a firm and 
uniform coagulation, with an acidity of from 90.65 to 0.80 per cent, 
for at that stage a mild-flavored cheese is obtained and at the same 
time sufficient acid is present to give a clear separation of the whey 
from the curd. The object of cutting and heating is to get rid of 
the desired quantity of whey and to remove much of the acidity 
with the least possible loss of curd. The best method of cutting the 
curd is to use regular cheese-curd knives, described above, which 
cut the curd into fairly uniform cubes from which the whey can be 
expelled with but small loss of finely broken particles of curd pass- 
ing through the drain cloth. ‘To break the curd or coagulum with a 
Fig. 1.—Stirring the curd during heating 
stirrer produces too many fine particles of curd, which are easily 
lost in draining. 
After the curd is cut, heat is turned under the vat, and the tem- 
perature is raised gradually to 115° to 125° F. At the Grove City, 
Pa., creamery, operated by the Bureau of Dairy Industry, a tempera- 
ture of 120° to 125° has given best results. Formerly a temperature 
of 95° to 105° was used for heating the curd; but when the cheese 
is made in large quantities it seems better to use a higher heating 
temperature and then cool immediately with cold water. Variation 
in the heat requirement depends upon the quantity of milk, the 
degree of acidity, the length of the period of heating, and the 
texture of cheese desired. The curd should be stirred gently at 
intervals (fig. 1) to prevent its cooking on the sides and bottom of 
