Steam as Leavening. In practically all
batters and doughs, a certain amount of
liquid is volatilized and helps to leaven the
mixture. Where the proportion of liquid
is high, as in popovers and cream puffs,
steam is the only leavening agent. Mix¬
tures leavened only by steam require a hot
oven to raise the liquid to the boiling
point very quickly. Such mixtures are
characterized by large central cavities, in
the case of popovers and cream puffs made
from batters, and by a decided increase in
volume in both batters and doughs. Steam
has great leavening ability, since water
increases in volume many times in changing
from liquid to steam. Pastry is the typical
dough leavened by steam.
Carbonated water was used at one time
in England in the preparation of so-called
aerated bread. This bread was made by
mixing the dough under pressure with
charged water. When the pressure was re¬
leased, the dough expanded. Further expan¬
sion occurred when the bread was baked.
In dilute form, alcohol may be used as
an aid in leavening. It volatilizes at a low
temperature, forming a gas that may help
to leaven certain mixtures. The brandy
and other alcoholic beverages used in fruit
cake, plum pudding, and pound cake are
primarily for flavor, yet there is some
leavening effect from them.
Baking Soda. All chemical methods of
leavening depend upon the liberation of
carbon dioxide from a carbonate by the use
of an acid. The carbonate used is the so-
called "baking soda” or sodium bicarbonate.
The chemical methods of leavening are
simple and easily controlled even in the
hands of the inexperienced, but they do not
develop flavor in the dough as the fermen¬
tation methods do, and they leave a residue
which in some cases may be undesirable.
In general, the chemical action which pro¬
duces leavening may be illustrated by the
following equation:
Soda + acid = carbon dioxide + a residue
salt + water
Probably the simplest of the chemical
means of leavening are those in which
soda is used in combination with some acid
liquid ingredient. It is important in using
soda to know just the amount to add, for
not only is an excess of soda unpalatable,
but it decreases somewhat the vitamin con¬
tent of the foods.
Sour milk and buttermilk are the acid-
containing liquids most used for chemical
leavening. The acid in both is the same,
lactic acid. In the souring of milk the
lactic acid is formed from lactose. After
eight per cent of lactic acid has been formed,
the lactic-acid fermentation stops. This is
indicated by the fact that the content of
lactose remains constant. On this basis and
also by neutralizing carefully measured
volumes of sour milk, it is found that the
amount of soda necessary to neutralize each
cup of milk is 8.36 grams, or, in household
terms, a scant half teaspoon.
[290]
When fruit juice is an ingredient of a
batter or dough, soda may be used to pro¬
duce carbon dioxide. Also the acid of cut¬
up fruit in cakes and cookies will combine
with soda to form some carbon dioxide.
Page 264
Presented as published in 1935. 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
Steam as Leavening. In practically all batters and doughs, a certain amount of liquid is volatilized and helps to leaven the mixture. Where the proportion of liquid is high, as in popovers and cream puffs, steam is the only leavening agent. Mix- tures leavened only by steam require a hot oven to raise the liquid to the boiling point very quickly. Such mixtures are characterized by large central cavities, in the case of popovers and cream puffs made from batters, and by a decided increase in volume in both batters and doughs. Steam has great leavening ability, since water increases in volume many times in changing from liquid to steam. Pastry is the typical dough leavened by steam.
Carbonated water was used at one time in England in the preparation of so-called aerated bread. This bread was made by mixing the dough under pressure with charged water. When the pressure was rereleased, the dough expanded. Further expan- sion occurred when the bread was baked.
In dilute form, alcohol may be used as an aid in leavening. It volatilizes at a low
temperature, forming a gas that may help to leaven certain mixtures. The brandy and other alcoholic beverages used in fruit cake, plum pudding, and pound cake are primarily for flavor, yet there is some leavening effect from them.
Baking Soda. All chemical methods of leavening depend upon the liberation of carbon dioxide from a carbonate by the use of an acid. The carbonate used is the socalled "baking soda” or sodium bicarbonate. The chemical methods of leavening are simple and easily controlled even in the hands of the inexperienced, but they do not develop flavor in the dough as the fermen- tation methods do, and they leave a residue which in some cases may be undesirable. In general, the chemical action which pro- duces leavening may be illustrated by the following equation:
Soda + acid = carbon dioxide + a residue salt + water
Probably the simplest of the chemical means of leavening are those in which soda is used in combination with some acid liquid ingredient. It is important in using soda to know just the amount to add, for not only is an excess of soda unpalatable, but it decreases somewhat the vitamin con¬ tent of the foods.
Sour milk and buttermilk are the acidcontaining liquids most used for chemical leavening. The acid in both is the same, lactic acid. In the souring of milk the lactic acid is formed from lactose. After eight per cent of lactic acid has been formed, the lactic-acid fermentation stops. This is indicated by the fact that the content of lactose remains constant. On this basis and also by neutralizing carefully measured volumes of sour milk, it is found that the amount of soda necessary to neutralize each cup of milk is 8.36 grams, or, in household terms, a scant half teaspoon.
[290]
When fruit juice is an ingredient of a batter or dough, soda may be used to pro¬ duce carbon dioxide. Also the acid of cut¬ up fruit in cakes and cookies will combine with soda to form some carbon dioxide.