Baking Soda vs. Baking Powder: What’s The Difference?

Have you ever wondered about the differences between baking soda and baking powder, and whether they can be used interchangeably? Why some recipes call for just one, and others call for both? Knowledge is power, and a deeper understanding of these two ingredients is important if you enjoy baking. Time for a quick science lesson!

A closeup look at baking soda vs. baking powder.

Baking Soda vs. Baking Powder

Both baking soda and baking powder are known as chemical leavening agents. In baked goods, leavening refers to the air that causes baked goods to rise in the oven. Yeast also causes baked goods to rise, but it’s a biological leavening agent as opposed to a chemical one.

So if baking soda and baking powder are both chemical leavening agents, how are they different?

A photo of baking soda and measuring spoons

What is baking soda?

Baking soda, also known as sodium bicarbonate, is a base mineral. When it’s added to an acid, a reaction occurs that produces carbon dioxide. The gas forms bubbles, and when trapped inside batter, tiny air pockets.

This is what causes cakes to rise as well as the light and fluffy textures necessary for a variety of baked goods. Some examples of acids you might find in baking include honey, cream of tartar, lemon juice, brown sugar, yogurt, and buttermilk.

What is baking powder?

Baking powder is a synthetic version of baking soda. It’s sodium bicarbonate mixed with an acidifying agent (usually cream of tartar) plus a drying agent. 

The acid is included to activate the sodium bicarbonate, and the drying agent is included because baking powder reacts to moisture alone. Since an acid is already present, adding any type of moisture (heavy cream, for example) will cause a reaction to occur. 

A photo of baking powder and spoons.

Double Acting Baking Powder vs. Single Acting Baking Powder

Baking powder is available in two forms: single acting and double acting. Single acting baking powder has a temporary reaction once it’s combined with a liquid ingredient, so it should be placed in the oven ASAP after activating it.

Double acting baking powder reacts when you first add moisture, then an additional reaction takes place during the baking process. So if you’re baking something that won’t go directly into the oven, it’s best to use double acting baking powder. 

I recommend using double acting baking powder in general as opposed to keeping two versions on hand. Are you with me so far? Good, let’s keep going.

Why do some recipes use both baking soda and baking powder?

Sometimes you’ll have enough baking soda in a recipe to neutralize the acid, but not enough to actually lift the batter. Adding too much baking soda can result in a unpleasant aftertaste, and it can also cause the batter to rise too quickly and then collapse. So in this instance, adding a small amount of baking powder will bring the required lift without ruining the flavor.

Why not just use all baking powder in this scenario? Baking soda also neutralizes the flavor of the acid, which is why buttermilk biscuits don’t taste sour. Without the baking soda, your baked goods might taste too acidic.

Baking soda also helps with the browning process, which is why you might find it in a pancake recipe, for example. The baking soda helps create that beautiful brown surface on the pancakes. This is also why it’s included in pretzel recipes.

How to substitute baking soda for baking powder

You can substitute baking soda for baking powder as long as there’s enough acid in the recipe to cause a reaction. For 1/2 teaspoon of baking soda, you need 1 cup of buttermilk, 1 teaspoon of vinegar, or 1 teaspoon of lemon juice. Keep in mind that baking soda is four times as strong as baking powder, so you need to use 1/4 the amount of baking soda. 

How to substitute baking powder for baking soda

You can technically substitute baking powder for baking soda by using quadruple the amount of baking powder. So if a recipe calls for 1/4 teaspoon baking soda, you can use 1 teaspoon baking powder. However, if you’ve been paying attention, you know that this could potentially impact the flavor of the recipe.

How to make homemade baking powder

To make your own baking powder, sift 2 tablespoons cream of tartar and 1 tablespoon baking soda through a fine mesh strainer into a small bowl. Repeat the sifting process an additional 2 times. Store in an airtight container at room temperature. 

The expiration date on a box of baking soda

How to test for expired products

Sometimes baking powder and soda will stop working before the expiration date on the box. This is more likely to be an issue with your baking powder. However, I recommend periodically checking to make sure they’re both still active before you risk wasting ingredients on a cake that never rises.

Testing baking soda to make sure it's still active by adding vinegar

How to test for expired baking soda:

  1. Add 2 tablespoons distilled white vinegar to a small bowl.
  2. Add 1/4 teaspoon baking soda to the vinegar. If the baking soda is still active, it will react with the acid and bubble up.

Testing for expired baking powder

How to test for expired baking powder:

  1. Measure 1/2 cup hot water into a small bowl.
  2. Add 1/2 teaspoon baking powder. The reaction won’t be quite as dramatic as the baking powder, but there will be fizzing and bubbles.

Ready to start baking?

Head over to my cakes and cupcakes recipe index!

About Jennifer Farley

Jennifer graduated from the Culinary Arts program at L’Academie de Cuisine in Maryland, and has worked professionally as a line cook, pastry chef, and cooking instructor. Her cookbook, The Gourmet Kitchen, was published in 2016 by Simon & Schuster.

Affiliate Disclaimer: Posts may contain affiliate links. I am a participant in the rewardStyle and Amazon affiliate programs, which help support Savory Simple by providing me with a small commission fee when you shop through my links, at no additional cost to you.

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