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Baking Powder Vs. Baking Soda

a glass jar containing baking soda


Baking powder vs. baking soda. Even experienced cooks sometimes get confused … I’ve had a few bumbles. They look the same. And they’re both leavening agents, used to help baked food rise. Leaveners are a foundation of baking … without the puff, a loaf of bread is a brick and a pancake turns into a tortilla. We require gases to be incorporated into dough or batter to give things a soft texture and make them fluffy and appealing. (it’s not always air, by the way, more often it’s CO2)



So, what is the difference? It’s all in the chemistry. Baking soda is a chemically “basic” powder that has to be used in tandem with an acid … an ingredient like lemon juice, vinegar, cream of tartar, honey or buttermilk. Formally known as sodium bicarbonate, baking soda is activated when combined with acid and a liquid.


Think about that science experiment you probably did in first grade, blending baking soda and white vinegar. The resulting reaction produces a plume of carbonic acid that fizzes up and out of the glass, bowl, or playdough volcano, as the case may be. It’s this same reaction that allows baked goods to rise and become light and fluffy. Carbonic acid has a flavor … a slightly acidic lemony taste you get in  mineral water, and carbonated beverages. But it breaks down quickly during baking into water and carbon dioxide.


Unlike baking soda, baking powder is a complete leavening agent, meaning it’s a mix that contains both a base (sodium bicarbonate, the same as baking soda) and the acid needed to produce a rise. The acid in baking powder reacts with sodium bicarbonate and releases carbon dioxide once it’s combined with a liquid. Baking powder also commonly includes cornstarch, added to prevent the acid and base from activating during storage. Baking powder is typically used when the recipe doesn’t call for any acidic ingredients.


Baking powders can be fast-acting, slow-acting, or double-acting, depending on the acids they contain. Some react with liquid, while others react with heat. Double-acting powders usually contain two acids—one for liquid, the other for heat. When a recipe calls for baking powder, it’s most likely referring to the double-acting kind.


For many recipes, an extended reaction is what you need, so the leavening doesn’t happen all at once. If you think about something like … muffins, that makes sense. You want a lifting of the batter during the initial reaction as you blend the dry baking powder with a liquid. And then, a second response partly through baking, when the heat activates round two and the gluten in the flour begins to stretch, cook and hold its shape for a fluffy final product.


Some recipes call for both baking soda and baking powder. Typically this is because the recipe contains an acid that needs to be offset by the baking soda but may not have enough of it to completely leaven the product.


The question is … can you substitute them in a recipe? It isn’t widely recommended, as the chemistry can become dicey. But if you have to, you can make it work. Swapping baking powder for baking soda won’t require additional ingredients, but baking soda is much stronger than baking powder. So you’d likely need around three times as much powder as you would soda to create the same rise.


If your recipe calls for baking powder and all you have at hand is baking soda, it’s even more tricky. Because baking soda lacks an acid, you have to make sure to add an acidic ingredient, such as cream of tartar, to activate the baking soda. As a rule of thumb, about 1 teaspoon of baking powder is equivalent to 1/4 teaspoon of baking soda.


So unless you get the proportion of base to acid just right, as it probably is in your written recipe, you might get a funky taste … either the bitterness of too much base, or the sourness of too much acid. Although my creative side resists it, in this case I suggest faithfully sticking to the recipe whenever you can because baking is less middle school science experiment and more tried-and-true precision chemistry.


This is Lael Gilbert for Bread and Butter.