What is the difference between baking soda and baking powder?
Baking soda is pure sodium bicarbonate and needs an acid in the recipe to make bubbles. Baking powder already contains baking soda plus an acid, so it only needs moisture.
Both are leavening agents: they release carbon dioxide gas, which makes batters and doughs rise. Baking soda reacts as soon as it meets an acidic ingredient, such as buttermilk, yogurt, lemon juice, vinegar, brown sugar or cocoa. Recipes using it should be baked quickly.
Baking powder contains baking soda, a dry acid such as cream of tartar and a starch to keep it dry. Most baking powder sold today is double-acting: it releases some gas when mixed with liquid and more when heated in the oven.
Can you swap them?
Baking soda is about three to four times stronger than baking powder. You can replace 1 teaspoon of baking powder with about a quarter teaspoon of baking soda plus an acid, but swapping without adjusting the recipe often gives a metallic taste or a flat cake.
Did You Know?
Baking soda has many uses beyond cooking, including cleaning, deodorizing refrigerators and soothing some insect bites.