- Baking soda reacts with an acid to cause batters and doughs to rise and spread while baking.
- Baking powder reacts with liquid and heat to create a light, fluffy texture in baked goods.
- While they sound similar, baking soda and baking powder cannot be used interchangeably.
- Visit Insider's Home & Kitchen Reference library for more stories.
It's common to find baking soda, baking powder, or a mixture of the two on the ingredients list for a baking recipe. But what exactly are they? Baking soda and baking powder are chemical leavening agents. While they both play a role in making batters or doughs rise — as well as changing the texture of food — they are not one and the same.
"While both leaveners create a rise, they work differently to get there," says Lindsey Johnson, baker and owner of Lady in the Wild West.
Baking soda and baking powder are distinct ingredients, and each serves a specific purpose. Because of the way they differ in make-up, they cannot be used interchangeably.
What is baking soda?
Baking soda is pure sodium bicarbonate. According to Johnson, it's used in baked goods such as cookies, muffins, and quick breads. When baking soda is paired with an acidic ingredient such as brown sugar, cocoa, sour cream, or buttermilk, it reacts with the acid. That reaction creates tiny bubbles of gas, or carbon dioxide, which makes a batter or dough rise and spread. "Think of the perfect chocolate chip cookie," says Johnson, referring to the chewy texture. "That's baking soda."
If you're out of baking soda, baking powder can be substituted by multiplying the amount called for by three. However, Johnson advises only doing this in a pinch because it can cause the taste and texture of the end product to be too dense or salty.
Baking soda can be stored unopened for up to three years, but once the box is open, that shelf-life begins to dwindle. Because baking soda has the ability to absorb odors and moisture, an opened box stored in a cool, dry pantry should be replaced after six months.
When to use baking soda
- Fudgy brownies. Baking soda helps to produce a dense, fudgy brownie.
- Chocolate chip cookies. Baking soda will help the cookie dough spread and create a delicious, chewy texture.
- Irish soda bread. Because of the buttermilk traditionally added to this quick bread, all you need is baking soda to create a rise instead of yeast.
- Banana bread. Baking soda will react with the acid in brown sugar to produce great texture and beautiful golden color.
What is baking powder?
Baking powder is made up of both sodium bicarbonate and a dry acid such as sodium aluminum sulfate or cream of tartar. It's used in baked goods such as cakes, biscuits, and pastries. According to Johnson, baking powder relies on the liquid in a mixture, such as water or milk. It reacts to the liquid first and then reacts again to heat. Both reactions produce tiny bubbles of gas, or carbon dioxide, causing the batter to rise and puff to create a light, airy texture.
Baking powder can be stored unopened for two years, but once the package is opened, that shelf-life is also reduced. Because baking powder reacts with liquid, any exposure to moisture over time can change how effective it is. Store opened baking powder in a cool, dry place for no more than one year.
When to use baking powder
- Biscuits. Baking powder reacts with the cold milk in this recipe first and then creates a rise in the oven to produce fluffy biscuits.
- Cakes. You can't achieve light, fluffy texture in a cake or cupcake recipe without baking powder working to create tiny air bubbles during the baking process.
- Fluffy sugar cookies. The addition of baking powder will help to create airy, delicate grocery store bakery-style sugar cookies.
Insider's takeaway
Baking soda and baking powder are not the same and cannot be used interchangeably. Baking soda reacts to the acid in a recipe, while baking powder reacts to liquid and heat. Baking soda changes the texture of baked goods by causing a batter or dough to spread, while baking powder produces light, fluffy texture.
Some recipes may call for baking soda or baking powder on their own, while others may require both ingredients to create the ideal balance for great texture.