What's the Difference Between Baking Soda and Baking Powder?
I've been baking for more than half of my life, and yet certain basic things still do not come naturally to me. Whenever I see "baking soda" or "baking powder" in an ingredient list, I always pause for a second. Which one is which again? Use the wrong one and your recipe is guaranteed to be a flop.
While these two ingredients are both leaveners that help baked goods rise, they do very different things. When baking soda (sodium bicarbonate) is mixed together with acidic ingredients such as vinegar, buttermilk, or citrus juice, it produces carbon dioxide, which helps the dough rise as it bakes. The ratio of baking soda to acid is very important—you don't want to use too much baking soda because it can give baked goods an unpleasant metallic aftertaste. Too little baking soda won't react properly with the acidic ingredient, producing heavy, flat results.
Baking powder contains baking soda, plus another acid in powdered form (usually cream of tartar). You do not need to combine baking powder with an acidic ingredient for it to work; it can leaven dough all by itself. Which is why baking powder is typically called for in recipes like a vanilla cake or shortbread cookies. Self-rising flour, a key ingredient in our Best-Ever Buttermilk Biscuits, also contains baking powder.
Watch: How to Make Our Best-Ever Buttermilk Biscuits
When a recipe calls for a mixture of baking powder and soda, two things happen: the baking soda balances out any acidic ingredients in the recipe, while the baking powder gives it the extra lift it needs in the oven.
If, like me, you also find that your brain freezes up when you come to "baking soda" in an ingredient list, I've developed a little trick to remind myself. Baking soda is in the fridge, baking powder is in the cabinet. Thinking about where the ingredients are in my kitchen never fails to straighten me out when I'm scanning a recipe.