222 BUTTER-MAKING. 
for inoculation are the same from day to day, the starter will 
be ripe at nearly the same hour every day, and, consequently, 
more uniform ripening results can be obtained. The notice- 
able coagulation of the starter when skim-milk is used will 
usually take place when there is about .6% of acidity. A 
slight coagulation will take place when there is about .5% of 
acidity, but it is hardly noticeable. The coagulation-point may 
vary with different samples of milk. 
If a mother-starter is to be kept any length of time it 
should be inoculated into a sample of good fresh pasteurized 
milk about every other day. If a mother-starter, or starter 
of any kind, is allowed to stand too long at a low temperature, 
the desirable germs will become dormant, and some undesirable 
germs will gradually gain a foothold. It is a good plan to 
carry any mother-starter along for two or three days before it 
is used to inoculate a large sample of milk. When the mother- 
starter is first prepared it sometimes contains an undesirable 
taste and smell from the medium in which the germs were 
put up at the laboratory. This smell and taste is eliminated 
by carrying it on two or three days previous to its use. 
While the starter, or mother-starter, is in the stage of 
ripening it should occasionally be gently stirred. As soon as 
coagulation of the milk begins, then starters of any kind should 
never be stirred. If a sample of coagulated milk is stirred 
before it is ready for use, it is more likely to ‘‘ whey off.” 
Length of Time a Starter Can be Carried.—In this country, 
even if special precautions are taken, it seems almost im- 
possible to carry on a starter for more than four weeks without 
having undesirable ferments enter. The length of time a starter 
can be carried undoubtedly depends-upon conditions, and the 
care with which it has been handled. When a starter is properly 
prepared, cooled gradually before coagulation, and not overri- 
pened, it will contain a smooth soft curd, and retain its mild acid 
flavor for at least a month. The Danes, who use starters in 
butter-making more regularly than any other people, are able to 
carry a starter along for six months or more without renewing it. 
