Baked goods such as cakes, muffins, and bread have a light, fluffy texture because of baking powder, a dry chemical leavening agent. It releases carbon dioxide into the batter or dough, differentiating it from natural leavener such as yeast, and that gas causes small bubbles in the mixture that expand and helps the baked good to rise as it cooks. Without leavener, baked goods are dense, flat, and hard.
By its nature, baking powder is gluten-free because it doesn't have wheat, rye, barley, or triticale, the four types of grains that contain the protein. However, some brands might add starch to commercial products to protect against early chemical reactions occurring in storage, and that starch isn't necessarily free from gluten.
Gluten in Baking Powder
Humid storage conditions can be a problem for commercial baking powder products, as the moisture may cause a chemical reaction to begin prematurely. When that occurs, the baking powder isn't usable when later bought by a customer.
To prevent this, some manufacturers add a form of starch. These days, it's normally cornstarch or potato starch, which means that the product is still gluten-free. However, in the past, manufacturers often added wheat starch, which is not gluten-free. In countries outside the United States, such as in the United Kingdom, some brands of baking powder might still have wheat starch. Therefore, it's important to read labels and double-check the ingredient list prior to purchase.
Using Baking Powder in Gluten-Free Recipes
When it comes to leavening, gluten-free recipes often need a little extra help—common gluten replacers simply aren't as elastic as regular gluten. Baking powder comes in two varieties: single-acting and double-acting. When engaging in gluten-free baking, reach for the double-acting baking powder. Here's the difference:
- Single-acting baking powder: When mixed with the wet ingredients that contain an acid, the baking powder begins its chemical reaction right away. The batter must go into the oven to bake immediately.
- Double-acting baking powder: The baking powder begins a chemical reaction when mixed with the wet ingredients. However, the product contains a second "high heat" acid that is activated by heat, so it begins a second chemical reaction while it bakes. This results in a higher, lighter texture.
There's one caveat: Double-acting baking powder often contains sodium aluminum sulfate (SAS), which can impart a metallic taste, particularly when extra baking powder is used, such as in gluten-free baking. Look specifically for brands that are marked "aluminum-free" to avoid this taste.
Make Your Own Baking Powder
If you can't find baking powder that you're sure doesn't contain gluten or if you're worried about cross-contamination issues, you can make your own baking powder with just three ingredients: 1 teaspoon baking soda, 2 teaspoons cream of tartar, and 1 teaspoon cornstarch. This will make 1 tablespoon of gluten-free baking powder.
Because the cornstarch helps stabilize the mixture, you can increase this recipe and keep it in an airtight container in the pantry for future use. Combine 2 tablespoons baking soda, 1/4 cup cream of tartar, and 2 tablespoons cornstarch.