6 BULLETIN 669, TJ. S. DEPARTMENT OF AGRICULTURE. 
termines to a great extent the softness or firmness of the curd. Under 
normal conditions it requires from 45 to 60 minutes to curdle milk; 
the exact time to set a given lot of milk will, of course, depend upon 
the temperature, acidity, rennet, and composition of the milk. 
RENNET OR PEPSIN. 
Commercial liquid rennet, One-third of an ounce, or five-sixths of 
a gram of powdered pepsin, is added to each 1,000 pounds of milk. 
The rennet should be diluted in a half pail of cold water, or if 
pepsin is used, the powder is first dissolved in a little cold water 
and then handled in the same manner as rennet. There is some ad- 
vantage, in the case of cream cheese, in using half an ounce of liquid 
rennet or 1 gram of powdered pepsin per 1,000 pounds of milk in- 
stead of the quantities specified. Sometimes powdered rennin is used 
as a curdling, agent, in which- case the quantity depends upon its 
strength. One gram of powdered rennin is usually, equivalent to 
4 or 5 grains of liquid rennet. 
The powdered pepsin or powdered rennet should be weighed, on an 
accurate balance and then dissolved in 20 times its weight of water 
warmed to 105° F. The solution is. then poured through a strainer 
cloth into* a dipper of cold water in order to remove any solid par- 
ticles. Under no circumstances should powders be dissolved until 
needed for use. Pepsin has given nearly as satisfactory results as 
rennet and is less expensive. 
All liquid curdling agents should be kept in a cold place in dark- 
brown bottles which are kept tightly corked. 
FILLINQ THE CANS. 
After being pasteurized and cooled down to 80° or 83° F. and the 
curdling agent added, the milk is drawn off from the faucets of the 
setting' vats, which should be placed close to the cellar. The work 
must be conducted rapidly so that the contents of the vat may be 
removed within half an hour, to avoid agitating the milk after it 
has. begun to set. Unless a sanitary connecting pipe is used in filling 
the shotgun cans it requires several workers to remove them as 
rapidly as they are filled. If not very carefully cleaned and 
thoroughly sterilized daily, the connecting pipe can not be kept 
in sanitary condition, and its use should be avoided. The shotgun 
cans are usually filled in the forenoon in order that the curd may be 
ready for drainage the following morning. 
DUMPING THE CURD. 
The following morning, if the termentation or ripening has 
progressed satisfactorily,, there should be about a quarter of an inch 
of whey, which is sufficient to form a scum on the surface of the 
curd. This is a fairly accurate sign of a proper fermentation, while 
