Though the earliest form of bread was made simply by
mixing flour and meal with water, and baking it, the tough,
hard cake thus formed was neither very digestible nor wholly
palatable. Experience probably taught that a light porous
dough was more desirable, and so a leavened bread came
into use. Doughs, or batters, are made light by means of
some gas, which, by its expansion, forms a spongy, porous
mass. Sometimes air is the gas used, and is beaten into the
batter to make it light, as in the case of sponge cake ; but
BREAD 241
more often carbon dioxide (often called carbonic acid gas) is
introduced. Carbon dioxide may be formed in the dough in
two ways : first, by the action of an acid upon a carbonate, such
as baking soda; and second, by the growth of yeast, and the
consequent fermentation of sugar. The latter is the oldest
method of producing the result, and in spite of many efforts
to introduce other processes, is still the most satisfactory.
The ancient leaven was made by mixing flour and water
together, and letting it stand until it fermented, and in
some places "salt rising bread" is still made in the same
way. The fermentation is caused by the wild yeast cells
that are always floating in the air, and that fall into the
exposed liquid. It is these wild yeasts which cause the
change of apple juice into cider. The objection to this
method of obtaining yeast is that bacteria and moulds, as
well as different varieties of yeast, find access to the liquid,
and often cause acetic or other acid fermentation, and give
a sour or bitter taste to the bread.
Yeast is a tiny, one -celled plant, about one two-
thousandth of an inch in diameter, belonging to the class of
budding fungi. The scientific name is Saccharomyces cerevi-
sece. Under the microscope the yeast cell is seen to be
round or oval, consisting of a cell wall filled with proto-
plasm. In the young, fresh cell, the cell contents appear
clear and homogeneous; but as the yeast grows older, the
protoplasm becomes granular, and fat droplets and vacuoles
appear. If a growing cell be watched, a bulging of the wall
near one end of the cell will be seen, and this gradually
increases until a new cell is formed. This daughter cell
finally becomes detached from the parent cell, but often it
first forms buds in its turn, so that a chain of cells is seen,
each cell representing an individual plant. This method of
reproduction is called budding. Under certain conditions
of temperature and moisture,, there appear in the interior of
242 HANDBOOK OF DOMESTIC SCIENCE
the yeast cells two, three, or four rounded bodies called
spores. These expand, and become surrounded with a wall ;
the wall of the mother cell is ruptured, and the spores are
set free as new cells, to bud, and produce a new generation
of yeast.
Yeast, like other living things, requires food. Moisture,
oxygen, some nitrogenous matter, salts or mineral matter,
and carbohydrates, especially sugary substances, are needed
for its growth. The temperature is also an important fac-
tor, 70° to 85° F. being the most favorable for active growth.
The cells, when moist, are killed at a temperature varying
from 130° to 160° F., though, when dry, they can sometimes
withstand a temperature of 212° F. Yeast is rendered in-
active by a low temperature, though it can withstand cold
better than heat.
Page 115
Presented as published in 1900. Historical recipes may not meet modern food-safety standards. Cook from the modern interpretation, not the original instructions.
AI-modernized reading of the original text
Though the earliest form of bread was made simply by mixing flour and meal with water, and baking it, the tough, hard cake thus formed was neither very digestible nor wholly palatable. Experience probably taught that a light porous dough was more desirable, and so a leavened bread came into use. Doughs, or batters, are made light by means of some gas, which, by its expansion, forms a spongy, porous mass. Sometimes air is the gas used, and is beaten into the batter to make it light, as in the case of sponge cake ; but
more often carbon dioxide (often called carbonic acid gas) is introduced. Carbon dioxide may be formed in the dough in two ways : first, by the action of an acid upon a carbonate, such as baking soda; and second, by the growth of yeast, and the consequent fermentation of sugar. The latter is the oldest method of producing the result, and in spite of many efforts to introduce other processes, is still the most satisfactory. The ancient leaven was made by mixing flour and water together, and letting it stand until it fermented, and in some places "salt rising bread" is still made in the same way. The fermentation is caused by the wild yeast cells that are always floating in the air, and that fall into the exposed liquid. It is these wild yeasts which cause the change of apple juice into cider. The objection to this method of obtaining yeast is that bacteria and moulds, as well as different varieties of yeast, find access to the liquid, and often cause acetic or other acid fermentation, and give a sour or bitter taste to the bread.
Yeast is a tiny, one-celled plant, about one two-thousandth of an inch in diameter, belonging to the class of budding fungi. The scientific name is Saccharomyces cerevisece. Under the microscope the yeast cell is seen to be round or oval, consisting of a cell wall filled with protoplasm. In the young, fresh cell, the cell contents appear clear and homogeneous; but as the yeast grows older, the protoplasm becomes granular, and fat droplets and vacuoles appear. If a growing cell be watched, a bulging of the wall near one end of the cell will be seen, and this gradually increases until a new cell is formed. This daughter cell finally becomes detached from the parent cell, but often it first forms buds in its turn, so that a chain of cells is seen, each cell representing an individual plant. This method of reproduction is called budding. Under certain conditions of temperature and moisture, there appear in the interior of
the yeast cells two, three, or four rounded bodies called spores. These expand, and become surrounded with a wall ; the wall of the mother cell is ruptured, and the spores are set free as new cells, to bud, and produce a new generation of yeast.
Yeast, like other living things, requires food. Moisture, oxygen, some nitrogenous matter, salts or mineral matter, and carbohydrates, especially sugary substances, are needed for its growth. The temperature is also an important factor, 70° to 85° F. being the most favorable for active growth. The cells, when moist, are killed at a temperature varying from 130° to 160° F., though, when dry, they can sometimes withstand a temperature of 212° F. Yeast is rendered inactive by a low temperature, though it can withstand cold better than heat.