Baking Powder

A chemical leavener made of baking soda, a dry acid, and a little starch to keep it dry. When it gets wet the soda and acid react and release carbon dioxide, and most supermarket baking powder is double-acting, so it gives a second burst of gas in the oven's heat. It's what lifts quick breads, biscuits, muffins, and many sourdough discard recipes.

By Henry Hunter · Updated October 1, 2026

Henry's notes from the bench

• Not sure if your can is still good? Drop a spoonful into hot water. If it fizzes hard, it's alive. If it barely bubbles, replace it.
• Baking powder and baking soda aren't interchangeable one for one. Use what the recipe calls for.