222 YEASTS AND MOLDS 
BrEeAD MAKING 
The flour is one of the first things to which the baker pays special 
attention. Miner (1917), in describing the manufacture of flour, divides 
it into three general types: 
I. Low grade 
II. Clear flour 
IIT. Patent flour 
The baker demands a uniform flour and to secure it he may resort to 
blending. Most of them use a baker’s ‘‘ patent ” flour which may be 
superior to the domestic “ patent.” This is carefully sifted and the 
other ingredients added such as salt, sugar, lard, malt extract, milk, 
water, yeasts, etc. In the straight dough method all of these are mixed 
and allowed to ferment for about five hours in a long trough. The 
temperature of this room is maintained at 27° C. with a relative humidity 
of 75 per cent. From the fermenting room the dough is taken to a 
divider where it is cut into any desired size. It may be worked a little, 
allowed to rise and molded for baking. In the larger bakeries this may 
be entirely a machine process. 
Yeast in Bread Making. Bread is one of the oldest foods in the 
preparation of which fermentative changes are involved. In the early 
days before commercial yeasts were available, the housewife had to 
reply on spontaneous fermentations. The organisms which induced 
these chance fermentations got into the sponge either from the air or 
along with one of the ingredients. Quite often, a portion of one batch 
was taken out and saved over to inoculate the next batch of bread. 
To-day the baker does not have to rely on liquid brewers’ yeast nor the 
housewife on the uncertain fermentations of wild yeasts. The pro- 
duction of compressed and dried yeasts caused a distinct advance to be 
made in the production of leavened foods. <A mixture of yeast and flour 
will ferment, but the addition of other substances such as potato water, 
malt water, will greatly accelerate the action of the yeasts. All of the 
constituents of the flour which are given above are concerned in bread 
making. The carbohydrates are precursors of the carbon dioxide and 
in the baked loaf they impart a rich brown color to the crust. Accord- 
ing to Wardall (1910) the flavor of the bread is not dependent on the 
strain of yeast which is used as a leaven. She used thirty-three pure 
strains of yeasts and could observe no difference in the flavor of bread 
leavened by them. She regarded the time of incubation as too short 
for the development of any special flavor. 
