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Baking
powder is a fine white powder used to make cakes and
biscuits leaven
(rise). Cooks add baking powder to flour mixtures
before baking them.
Chemicals in baking powder react with air and
a liquid (usually water or
sweet milk) to form carbon dioxide gas.
Bubbles of carbon dioxide become
trapped in the flour mixture. The
bubbles expand when they are heated
and make the mixture rise.
All baking
powders contain starch, baking soda (sodium bicarbonate),
and
acid-forming ingredients. The starch keeps the powder dry and
prevents
it from acting until a liquid is added. Baking soda reacts with
the
acid-forming ingredient to produce carbon dioxide. Different kinds
of
baking powders contain different acid-forming ingredients. Tartrate
baking powders contain cream of tartar and tartaric acid as
acid-forming
ingredients. Phosphate powders have calcium
dihydrogen phosphate.
Sulfate powders contain sodium aluminum
sulfate, or alum. Combination,
or double-acting, powders have
phosphate and sulfate.
Baking
powders differ in speed of reaction. Sulfate powder is the
slowest
baking powder. It does not react fully until heated. Tartrate and
phosphate powders are the fastest. They react as soon as they are
mixed
with a liquid. Combination powders are the most widely used
type. They
react equally well in both the mixing and baking processes.
Baking soda
and sour milk have the same rising effect on flour
mixtures as baking
powder and sweet milk.
Kay Franzen
Jamieson, Ph.D., Food Consultant. |
