Running out of cornstarch mid-recipe is a common kitchen snag, but you don’t need to abandon your dish. This guide covers seven reliable alternatives—from common pantry staples like all-purpose flour and potato starch to clever swaps like arrowroot and rice flour—so you can thicken soups, sauces, gravies, and even baked goods without a trip to the store. Each substitute comes with the exact ratio and method to match cornstarch’s glossy, clear finish as closely as possible.
Ingredients
- For a slurry (to replace 1 tablespoon cornstarch): 2 tablespoons all-purpose flour (18 g) OR 1 tablespoon potato starch (10 g) OR 1 tablespoon arrowroot starch (10 g) OR 1.5 tablespoons rice flour (12 g) OR 1 tablespoon tapioca starch (10 g) OR 1 tablespoon kudzu starch (10 g) OR 2 tablespoons masa harina (18 g)
- Cold water or broth: 2–3 tablespoons (30–45 ml) to make the slurry
- For the recipe you are thickening: your usual liquid (soup, sauce, gravy) – about 2 cups (480 ml) for testing ratios
Instructions
- Choose your substitute based on what you have and what you’re making. For clear, glossy sauces and fruit pies, use arrowroot, potato starch, tapioca, or kudzu. For opaque, creamy soups and gravies, use all-purpose flour or masa harina. For Asian stir-fries, use potato starch or rice flour.
- Make a slurry: In a small bowl, whisk your chosen starch with the cold water or broth until completely smooth. Never add starch directly to hot liquid—it will form lumps.
- Add to hot liquid: Slowly pour the slurry into your simmering soup, sauce, or gravy while whisking constantly. Make sure the liquid is at a gentle simmer, not a rolling boil.
- Cook to activate: Let the mixture simmer for 1–2 minutes (for arrowroot, potato, tapioca, kudzu, or rice flour) or 3–5 minutes (for all-purpose flour or masa harina) until it thickens and any raw flour taste is gone. Stir frequently to prevent sticking.
- Adjust consistency: If the sauce is still too thin, mix another teaspoon of starch with a tablespoon of cold water and add it in, then simmer again. If it’s too thick, whisk in a splash of warm liquid.
- Season and serve: Taste and adjust salt and other seasonings, as some starches (especially flour) can dull flavors slightly. Serve immediately.
Tips
- Ratio matters: Cornstarch is a powerful thickener. When substituting, use roughly half the amount of arrowroot, potato starch, or tapioca starch as you would cornstarch. For flour, use double the amount. For rice flour and masa harina, use 1.5–2 times the amount.
- Acidic ingredients: Cornstarch breaks down in acidic liquids (like lemon juice or vinegar), so arrowroot or potato starch are better choices for those recipes—they remain stable.
- Don’t over-stir: Once a starch-thickened sauce is done, avoid vigorous stirring or boiling for too long, as this can break down the starch and thin the sauce again.
- Freezer-friendly?: Sauces thickened with cornstarch can become spongy when frozen. Arrowroot and tapioca freeze better, while flour-thickened gravies also hold up decently. If you plan to freeze, choose one of those.
Serving Suggestions
Use these substitutes in any recipe that calls for cornstarch: stir-fry sauces (like orange chicken or beef and broccoli), fruit pie fillings, puddings, custards, soups, stews, and gravies. For a classic example, try thickening a simple pan gravy with all-purpose flour after roasting chicken, or use arrowroot to make a glossy lemon sauce for fish.
Variations
- Gluten-free option: Use arrowroot, potato starch, tapioca, or rice flour instead of all-purpose flour. These are all naturally gluten-free.
- Low-carb option: Use xanthan gum (but only a tiny pinch, about 1/4 teaspoon per cup of liquid) or glucomannan powder, but note these require different techniques—whisk in with a blender to avoid clumping.
- For baking: In cakes or cookies that call for cornstarch to soften gluten, substitute an equal amount of rice flour or potato starch for a similar tender crumb.
- For crispy coatings: To dredge chicken or tofu before frying, potato starch or rice flour give an even crispier crust than cornstarch.
Storage and Reheating
Store all starches (cornstarch, arrowroot, potato starch, etc.) in a cool, dry place in an airtight container. They have a long shelf life—up to 2 years—but check for off odors or clumping. Once a sauce or soup is thickened, refrigerate leftovers in a covered container within 2 hours. Most thickened dishes keep for 3–4 days in the fridge. Reheat gently on the stovetop over low heat, stirring often; add a splash of broth or water if it has thickened too much. Avoid microwaving at high power, as it can cause the starch to break down and separate. Sauces thickened with cornstarch or flour do not freeze well (they can become watery), so it’s best to make only what you’ll eat within a few days.
Frequently Asked Questions
Can I use baking powder or baking soda as a thickener? No. Baking powder and baking soda are leavening agents, not thickeners. They will not thicken liquids and will alter the taste and texture of your dish.
What is the best substitute for cornstarch in a fruit pie? Arrowroot or tapioca starch are excellent choices because they thicken at a lower temperature and produce a clear, glossy gel that doesn’t dull the fruit’s color. Use about half the amount of cornstarch called for.
Why does my sauce become thin again after I add a cornstarch substitute? This usually happens if you boil the sauce too vigorously or for too long after adding the starch. Starch molecules break down with excessive heat and agitation. Also, if you added the slurry before the liquid was hot enough, the starch may not have activated properly.
Can I use almond flour or coconut flour instead of cornstarch? No, these nut flours do not have the same thickening power and will add a grainy texture and distinct flavor. Stick to starches or all-purpose flour.
Is potato starch the same as potato flour? No. Potato starch is a fine, powdery starch with neutral flavor and strong thickening power. Potato flour is made from whole peeled potatoes and has a stronger potato flavor and heavier texture. Use potato starch for thickening, not potato flour.
How do I substitute cornstarch in a recipe that uses it for coating before frying? For a crispy coating, use potato starch, rice flour, or tapioca starch in equal amounts. They create a light, crunchy crust similar to cornstarch. All-purpose flour will work but will be heavier and less crispy.
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Safety notes: safe minimum internal temperatures from USDA FSIS; raw and undercooked fish guidance from the U.S. FDA. Food safety notes
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