rounded tablespoon baking powder

Baking powder is a chemical leavening agent composed primarily of baking soda (sodium bicarbonate), one or more acid salts, and a moisture-absorbing ingredient such as cornstarch or aluminum silicate. Most commercial baking powders are "double-acting," meaning they release carbon dioxide gas in two stages: when moistened and when heated, allowing bakers greater control over rise timing during preparation and baking.

The ingredient was developed in the 19th century as a more convenient alternative to yeast and saleratus (potassium bicarbonate). Modern formulations typically contain about 30% sodium bicarbonate, 5-12% acidic components (such as cream of tartar, sodium aluminum sulfate, or monocalcium phosphate), and the remainder as cornstarch or other inert fillers. Single-acting baking powders, still used in some industrial applications, release gas only when heated.

Baking powder is essential in quick breads, cakes, cookies, pancakes, waffles, and biscuits, where it provides rise and a tender crumb structure without requiring fermentation time. It is particularly valued in American and European baking traditions where speed and consistency are priorities. The ingredient works by creating small gas bubbles throughout a batter or dough, resulting in a light, airy texture. Proper measuring is critical—too little produces dense results, while excess can cause a bitter, metallic taste and surface cracking. It should be stored in a cool, dry place and replaced annually to maintain potency.