Baking Powder vs. Baking Soda

Ask Peggy

Peggy Woodward, RD

Dear Peggy: Could you explain the difference between baking powder and baking soda? —S.B., Jordan, Montana

Baking soda and baking powder both produce carbon dioxide gas, which helps leaven baked goods, but they react differently. Baking soda is made up of sodium bicarbonate, which must come in contact with an acidic ingredient—such as buttermilk, cocoa, brown sugar, sour cream, vinegar, molasses or cream of tartar—to work. Baking powder is made up of baking soda, an acid and cornstarch. Cornstarch keeps the baking powder and acid separate and moisture-free until ready to use.

Sometimes, a recipe has both baking soda and baking powder, which seems redundant, but there's a good reason. Baking powder is a reliable leavener because it already includes the perfect amount of acid. Baking soda can help neutralize acidic ingredients.

Keep in mind, baking soda is more powerful than baking powder. Usually, 1/4 teaspoon of baking soda is needed to leaven 1 cup of flour, but you'd need 1 to 1-1/4 teaspoons baking powder to leaven the same amount. Quick breads, muffins, pancakes and waffles and batters with heavy ingredients—like candied fruit, bananas or pumpkin—may require more soda or powder.