FERMENTED MILKS. 13 
curd than at temperatures inducing a more rapid acid production. 
As soon as a fine curd has been formed the milk should be cooled 
promptly to below 50° F. to prevent the contraction and toughening 
of the curd. 
Buttermilk made in the usual way as a by-product of buttermaking, 
and especially buttermilk obtained by churning pasteurized cream, is 
improved by mixing with it about 10 per cent of a skim-milk culture 
of the Bacillus hulgaricus. Directions for the preparation of this 
culture will be found on page 23. 
This culture not only gives the buttermilk a sharper and more 
agreeable flavor, but on account of its viscous nature it gives it a 
smoother texture and prevents the separation of the curd from the 
whey. Detailed directions for the preparation of buttermilk by this 
method may be found in a circular of the Illinois Agricultural Ex- 
periment Station (52). 
MAKING BUTTEKMILK IN THE HOME. 
A more nearly uniform product can be obtained if it is made on a 
large scale, and if good buttermilk can be purchased from a reliable 
milk dealer at a reasonable price it is not advisable to attempt to make 
it on a small scale. However, it is possible to make buttermilk in 
the home by following in a small way the directions for making 
buttermilk on a commercial scale. It is necessary first to secure a 
culture or starter, which is merely milk containing the lactic- acid or 
sour-milk bacteria free or very nearly free from other kinds. These 
bacteria are present in any normal milk, and it is only necessary to 
provide conditions favoring their growth to obtain them in a state of 
purity. 
This may be done by following the directions on page 11 for obtain- 
ing cultures for making buttermilk on a large scale. When the cul- 
ture is obtained it will not be necessary to carry a small culture to 
inoculate a larger amount. 
When the culture is obtained proceed as follows : 
(1) Heat 1 quart of milk, which may be skimmed, in a double 
boiler for at least one-half hour. 
(2) Allow the milk to cool to about 75° or 80° F. 
At this temperature the outside of the container will feel warm 
to the hand. Add one teaspoonful of the fresh culture, transfer to 
a bottle or covered fruit jar, and put away in a warm place. One of 
the vacuum- jacketed bottles will be found very convenient for this 
purpose, because the milk can be held at a nearly constant tempera- 
ture favorable to the growth of the lactic-acid bacteria. 
(3) On the following day shake the bottle thoroughly to break up 
the curd and put the product on ice to cool. 
