Baking powder

Baking powder is a dry chemical leavening agent, a mixture of a carbonate or bicarbonate and a weak acid, combined with a desiccant like cornstarch to prevent the base and acid from reacting prematurely. When moistened and heated, it releases carbon dioxide gas through an acid–base reaction, which expands bubbles in a batter or dough, increasing the volume and lightening the texture of baked goods. The first commercially sold baking powder was Borwick's Baking Powder, launched in England in 1842 by George Borwick, who spent eleven years perfecting a formula passed to him by his father-in-law, a chemist, as a yeast substitute for home baking. The following year, Alfred Bird developed his own single-acting baking powder, which releases all its carbon dioxide as soon as it is dampened. In 1856, Eben Norton Horsford, the Rumford Professor at Harvard University, received an American patent for monocalcium phosphate for baking powder, and in the 1860s he developed the first double-acting baking powder, which releases some carbon dioxide when dampened and more when heated. Baking powder is used instead of yeast where fermentation flavors are undesirable, where the batter lacks the elastic structure to hold gas bubbles for more than a few minutes, or to speed production. Because carbon dioxide is released faster through the acid–base reaction than through fermentation, breads made with chemical leavening are called quick breads. The introduction of baking powder revolutionized baking by minimizing time and labor, leading to new types of cakes, cookies, biscuits, and other baked goods. Most commercial baking powders contain sodium bicarbonate and one or more acid salts, such as monocalcium phosphate, sodium aluminium sulfate, sodium acid pyrophosphate, or cream of tartar. Double-acting powders use both fast-acting acids, which react at room temperature, and slow-acting acids, which react when heated, increasing reliability by making the time between mixing and baking less critical. Starch components like cornstarch, flour, or potato starch serve as desiccants to absorb moisture, prolong shelf life, and improve flow and measurement accuracy.