Baking Soda vs. Baking Powder: The Differences Between These Popular Leavening Agents

When it comes to baking yeast-free treats like cookies, muffins, quick breads, and cakes, you usually can't achieve stellar results without baking soda or baking powder. Sometimes a recipe will call for both, other times it lists one, but rarely does it omit the category of leavening agents altogether. (Yeast, by the way, is also a leavening agent.)

While these fine white powders are similar, lending baked goods a light structure with optimal results, they are not the same thing—each has its own reaction in the baking process. We turned to a few expert bakers to demystify the kitchen science behind these pantry staples and discover what sets them apart.

What Is Baking Soda?

Baking soda, also called bicarbonate of soda, is sodium bicarbonate, through and through. It's pure alkaline, or a base, and resembles baking powder appearance-wise.

What Is Baking Powder?

Baking powder is a mixture of baking soda plus an acidic ingredient, typically tartaric acid (cream of tartar), and a thickener, like cornstarch. (Note that you can make homemade baking powder by stirring these ingredients together.)

Single-Acting vs. Double-Acting Baking Powder

If you're choosing between double-acting baking powder (which reacts twice in recipes—once when it gets wet and again when it is exposed to heat) and single-acting baking powder (which reacts just one time, when liquid is added), go for the former. "Be sure to purchase double-acting (so it will activate when it first gets wet, and then again when it's hit with the oven heat) and aluminum-free (to avoid a metallic taste)," says Anna Gordon, chef, and founder of The Good Batch, a Brooklyn-based bakery.

Why You Need Baking Soda and Baking Powder in Recipes 

"Baking soda and powder are major players in the bakery, and they each have their own little tricks and advantages," says Gordon.

They Promote Leavening and Browning

Both agents are integral to the chemistry of baking. "Baking soda and baking powder are both chemical leaveners that are used to enhance the expansion that is created when a liquid turns into steam during baking," explains Dan Langan, professional pastry instructor and author of the forthcoming cookbook, Bake Your Heart Out: Foolproof Recipes to Level Up Your Home Baking.

These leavening agents cause dough or batter to rise and also help baked goods hold their shape in the oven. Baking soda is something of a workhorse, too, boosting browning and delaying the setting of batters. "This is why soft pretzels are dipped in a soda solution (to promote browning) and cookies with more baking soda spread more (delayed setting of cookie dough lends more time for the dough to spread)," says Langan.

They Save Time

They're also time-savers. "Unlike yeast, which is another type of leavener and takes hours to ferment and activate, these powders are quick and super handy for leavening baked goods like cookies and cakes," says Gordon.

How Baking Soda and Baking Powder React With Other Ingredients

Each leavening agent reacts with different ingredients.

Baking Soda Reacts With Acid

"Baking soda reacts with acidic liquid ingredients like buttermilk, molasses, honey, lemon juice, and yogurt to create carbon dioxide gas that makes baked goods rise," says Yossy Arefi, baker and author of Snacking Cakes: Simple Treats for Anytime Cravings: A Baking Book and the forthcoming Snacking Bakes: Simple Recipes for Cookies, Bars, Brownies, Cakes, and More.

The chemical reaction is lightning-fast, producing air bubbles needed for an ethereal texture. "It is activated as soon as it gets wet so recipes with baking soda are best baked right after mixing," says Arefi. 

Baking Powder Reacts With Any Liquid

Baking powder's acidic component, cream of tartar, is built in and reacts with the included alkaline baking soda when it comes in contact with any liquid. "Baking powder is a one-stop-shop blend of baking soda and an acidic agent, and will work its magic on its own," says Gordon. 

In other words, baking powder creates carbon dioxide gas by itself, no matter which liquid goes into the mixing bowl. "That's why baking powder will fizz when added to a glass of water," says Langan.

Substituting Baking Soda and Baking Powder

How can you master a recipe if (horrors!) you're clean out of baking soda? "The general idea is that baking soda is four times more powder than baking powder," says Langan. When substituting with baking powder, use 1 teaspoon of baking powder in place of each 1/4 teaspoon of baking soda.

If your cabinet is bare of baking powder, use 1/4 teaspoon of baking soda in place of each teaspoon of baking powder.

When to Use Baking Soda vs. When to Use Baking Powder

Now that you know what each leavener brings to a recipe, when is it best to use baking powder vs. baking soda—and why do some recipes call for both?

Recipes Using Baking Powder

"Baking powder works well with more alkaline recipes like a cake made with Dutch process cocoa powder or cookies that don't contain any acidic ingredients," says Arefi (like this glazed chocolate cake, for example). But acidic elements aren't completely off the table. "Baking powder can also be used in recipes with acidic ingredients which can help create a more soft and tender crumb," she says.

Baking powder also proves indispensable in recipes where you don't want to downplay that acid. "We love buttermilk for its tang (thank you, acid) and adding baking soda would neutralize that tang. So using baking powder in your buttermilk biscuits gives you lift without neutralizing the buttermilk's flavor," says Langan.

Recipes Using Baking Soda

Recipes requiring baking soda also call for an acidic ingredient, like buttermilk, yogurt, chocolate, and/or brown sugar. Streusel banana bread is one example; chocolate date cake is another. And given its browning abilities, it's almost always used in chocolate chip cookie recipes.

Recipes Using Both

Oftentimes, recipes utilize both kitchen staples. Case in point: our morning glory muffins and zucchini nut bread. "I use baking soda and powder together in recipes that have a lot of acidic ingredients, like a cake batter, so the baking soda is working to mellow out the acidic flavors and the baking powder is solely dedicated to leavening," says Gordon. 

Arefi adds that for some cakes and cookies, the combination of the two creates the ideal texture, lift, and browning effect. Maybe it's time to mix up a few recipes and see for yourself.