Why corn starch is gluten free
Corn starch (cornstarch in U.S. English) is the pure starch fraction of the corn endosperm. The wet-milling process steeps corn in dilute sulfurous acid, separates germ, fiber, gluten (corn zein, not wheat gluten), and starch — leaving a pure starch product with no detectable wheat, barley, or rye protein.
Best GF-certified corn starch brands
- Bob’s Red Mill — GFCO certified, dedicated facility section
- Anthony’s Organic Corn Starch — batch tested GF
- Argo Corn Starch — naturally GF, not certified but mainstream celiacs report safe
- Clabber Girl — naturally GF
- Rumford — naturally GF
How to substitute for wheat flour as a thickener
Corn starch has roughly twice the thickening power of wheat flour. Standard ratio: 1 tablespoon cornstarch = 2 tablespoons all-purpose flour. Always mix cornstarch with cold liquid first (a “slurry”) before adding to hot sauces — adding directly to hot liquid causes clumping.
Don’t confuse with…
- Corn flour — finely ground whole corn, naturally GF
- Cornmeal — coarser ground corn, naturally GF
- Corn syrup — sweetener derived from cornstarch, naturally GF
- Modified corn starch — chemically/physically modified cornstarch, naturally GF
Sources
- Gluten and Food Labeling — FDA (2024)
- Is Cornstarch Gluten Free? — Beyond Celiac (2024)