Most baking powder sold in the United States is gluten-free, but not all of it. Baking powder is a mixture of several ingredients, and one of them, a starch used to prevent clumping, could theoretically contain gluten. In practice, major U.S. brands use cornstarch rather than wheat starch, making them safe for people with celiac disease or gluten sensitivity. Still, checking the label is the only way to be sure.
What’s Actually in Baking Powder
Baking powder contains three components: baking soda (the leavening base), an acid like cream of tartar (which activates the baking soda), and a starch that acts as a buffer to absorb moisture and keep the powder from clumping or reacting prematurely in the container.
That starch is the only ingredient that could introduce gluten. In the U.S., cornstarch is the standard choice, and corn is naturally gluten-free. However, some brands, particularly those sold outside the U.S., may use wheat starch instead. If wheat starch is present, it will be listed on the ingredient label, since wheat is one of the major allergens that must be declared by law.
Baking Soda Is a Different Story
Baking soda is pure sodium bicarbonate, a single chemical compound with no additives. It is inherently gluten-free regardless of the brand. The confusion between baking soda and baking powder trips people up, but the distinction is simple: baking soda is one ingredient, baking powder is a blend. The blend is where gluten could sneak in.
How to Tell If Your Baking Powder Is Safe
Flip the container over and look at two things. First, the ingredient list: if it says “cornstarch” (or rice starch, potato starch, or tapioca starch), the product is gluten-free. If it lists wheat starch, it is not. Second, look for a “gluten-free” label. Under FDA rules, any food labeled gluten-free must contain less than 20 parts per million of gluten, whether the product is naturally free of gluten-containing grains or has been processed to remove it. That 20 ppm threshold is the internationally recognized safety cutoff for people with celiac disease.
Popular U.S. brands like Clabber Girl, Rumford, and most store brands use cornstarch and are labeled gluten-free. If you’re buying an unfamiliar brand or an imported product, the ingredient list is your safeguard.
Making Your Own Gluten-Free Baking Powder
If you want complete control over what goes into your baking, homemade baking powder takes about 30 seconds to mix. The ratio is straightforward: use twice as much cream of tartar as baking soda. A practical batch is 1 cup of cream of tartar to half a cup of baking soda. Adding a tablespoon of gluten-free starch (cornstarch, rice starch, or potato starch) helps if you plan to store the mixture rather than use it immediately.
Without the starch buffer, the baking soda and cream of tartar can slowly react with ambient moisture, losing their leavening power over time. If you mix only what you need for a single recipe, you can skip the starch entirely. Store any leftover homemade baking powder in an airtight container in a cool, dry place.
Cross-Contamination Risks
Even when baking powder itself is gluten-free, cross-contamination in your kitchen can be an issue. Dipping a measuring spoon into your baking powder after it touched wheat flour introduces trace gluten into the container. For households where both gluten-free and regular baking happen, keeping a dedicated container of baking powder for gluten-free recipes prevents this problem. Some people with celiac disease also look for baking powder that carries a third-party gluten-free certification (such as GFCO), which involves testing and facility audits beyond what the FDA label requires.