Baking powder is a dry chemical leavening agent used in cooking, mainly baking. It is most often found in quick breads like pancakes, waffles, and muffins. When dissolved in water the baking powder's ingredients react and emit carbon dioxide gas which expands, producing bubbles to leaven the mixture. Baking powder is used instead of yeast because its action is instantaneous, while yeast takes two to three hours to produce its leavening action.

Most modern baking powders are double acting, that is, they contain two acid salts, one which reacts at room temperature, producing a rise as soon as the dough or batter is prepared, and another which reacts at a higher temperature, causing a further rise during baking. Common low-temperature acid salts include cream of tartar, calcium phosphate, and citrate. High-temperature acid salts are usually aluminium salts, such as calcium aluminium phosphate. Baking powders that contain only the low-temperature acid salts are called single acting.

History

Traditional baking powder was composed of a mixture of tartaric acid and bicarbonate of soda (baking soda), a quantity of flour or cornstarch usually being added to reduce the strength.

While various baking powders were sold in the first half of the 19th century, our modern variants were discovered by Alfred Bird. August Oetker, a German pharmacist, made baking powder very popular when he began selling his mixture to housewives. The same recipe he created in 1891 is still sold as Backin in Germany. Oetker started the mass production of baking powder in 1898 and patented his technique in 1903.

Eben Norton Horsford, a student of Justus von Liebig, who began his studies on baking powder in 1856, eventually developed a variety he named in honor of Count Rumford. By the mid-1860s "Horsford's Yeast Powder" was on the market as an already mixed leavening agent, distinct from separate packages of calcium acid phosphate and sodium bicarbonate. This was packaged in bottles, but Horsford was interested in using metal cans for packing; this meant the mixture had to be more moisture resistant. This was accomplished by the addition of corn starch, and in 1869 Rumford began the manufacture of what can truly considered baking powder.

During World War II, Byron H. Smith, an inventor in Bangor, Maine, created a substitute product for American housewives, who were unable to obtain baking powder, cream of tartar or baking soda due to war food shortages. Named "Bakewell", a mixture of sodium pyrophosphate and corn starch, the product is still part of regional culinary history. When combined with baking soda, it is essentially the same as any single-acting baking powder, the only difference being that the acid is sodium pyrophosphate.

In 2006 the development of Rumford Baking Powder was designated an ACS National Historical Chemical Landmark in recognition of its significance for making baking easier, quicker, and more reliable.

Usage

Generally (in countries where the cup is used as a standard measure in cookery) one teaspoon (5ml) of baking powder is used to raise a mixture of one cup (200-250ml) of flour, one cup of liquid, and one egg. However, if the mixture is acidic, baking powder's additional acids will remain unconsumed in the chemical reaction and often lend an unpleasant chemical taste to food. High acidity can be caused by ingredients like buttermilk, lemon, yoghurt, citrus, or honey. When excessive acidity is present, some of the baking powder is replaced with baking soda. For example, one cup of flour, one egg, and one cup of buttermilk requires only ½ teaspoon of baking powder -- the remaining leavening is caused by buttermilk acids reacting with ¼ teaspoon of baking soda.

Moisture and heat can cause baking powder to lose its effectiveness over time, and commercial varieties have a somewhat arbitrary expiration date printed on the container. Regardless of the expiration date, the effectiveness can be tested by placing a teaspoon of the powder into a small container of water. If it fizzes energetically, it's still active and usable.

Substituting in recipes

Baking powder is generally just baking soda mixed with an acid, and a number of kitchen acids may be mixed with baking soda to simulate commercial blends of baking powder. Vinegar (dilute ethanoic acid), especially white vinegar, is also a common acidifier in baking; for example, many heirloom chocolate cake recipes call for a tablespoon or two of vinegar. Where a recipe already uses buttermilk or yoghurt, baking soda can be used without cream of tartar (or with less). Alternatively, lemon juice can be substituted for some of the liquid in the recipe, to provide the required acidity to activate the baking soda.

Aluminum

Baking powders are available both with and without aluminum compounds. Some people prefer not to use baking powder with aluminum because they believe it gives food a vaguely metallic taste, and because of a possible (but controversial) link between aluminum consumption and Alzheimer’s disease (see Aluminum#Health_concerns).

See also

• Calumet Baking Powder Company
• Clabber Girl

References

External links

• Design and manufacture of baking powder