The best cornstarch substitutes depend on what you're making

Cornstarch thickens sauces, gravies, and pie fillings by absorbing liquid and turning it into a gel. If you don't have cornstarch on hand, potato starch, arrowroot powder, and tapioca starch work almost identically — they thicken at roughly the same ratio and produce similar results. For baking, flour and baking soda mixed with an acid can replace it, though the texture will shift slightly. What you choose depends on whether you're thickening a sauce, filling a pie, or baking a cake.

The most important thing to know: not every substitute works the same way in every dish. A thickener that works perfectly in gravy might make a cake dense. This guide walks you through which substitute works where, how much to use, and what to expect from the result.

Key Takeaways

  • Potato starch, arrowroot powder, and tapioca starch thicken liquids at nearly the same strength as cornstarch and work in sauces, gravies, and pie fillings.
  • Flour thickens but requires about twice as much and must be cooked longer to remove the raw flour taste.
  • Baking soda and an acid (buttermilk, yogurt, vinegar) can replace cornstarch in cakes and quick breads by providing lift instead of structure.
  • Xanthan gum thickens without heat and works in cold sauces, but use only one-quarter the amount of cornstarch.
  • The best choice depends on the dish — what works in a stir-fry sauce may not work in a custard or cake.

Potato starch, arrowroot, and tapioca for sauces and gravies

These three starches are the closest match to cornstarch. They thicken at the same ratio — use the same amount you would use of cornstarch — and they produce a clear, glossy sauce without lumps if you mix them with cold water first before adding to hot liquid.

Potato starch is the easiest to find in most grocery stores and costs less than arrowroot. It works in gravies, pan sauces, and Asian stir-fry sauces. The result is nearly identical to cornstarch.

Arrowroot powder produces a slightly clearer sauce than cornstarch and works well in fruit pie fillings because it doesn't cloud the filling. It also works in sauces for meat and poultry. Arrowroot costs more and is less common, but it's worth seeking out if you want a transparent filling.

Tapioca starch (also called tapioca flour) thickens at the same strength and works in any dish cornstarch does. It's less common in regular grocery stores but widely available online. The texture is nearly identical to cornstarch.

Flour as a thickener in sauces and gravies

Flour thickens but not as efficiently as cornstarch. You'll need about twice as much flour as cornstarch — if a recipe calls for 1 tablespoon of cornstarch, use 2 tablespoons of flour instead. Mix the flour with cold water or cold broth to make a paste (called a slurry) before stirring it into hot liquid, or it will clump.

The main drawback is that flour must cook for at least 1 to 2 minutes after you add it, or the sauce will taste like raw flour. Cornstarch and the starches above need only 30 seconds to a minute. This matters less in a long-simmering gravy but more in a quick pan sauce.

Flour also produces a slightly opaque, matte sauce rather than the glossy finish cornstarch gives. For beef stew or pot roast gravy, this is fine. For a clear fruit sauce or Asian glaze, it's noticeable.

Baking soda and acid for cakes and quick breads

Cornstarch in cake recipes does two things: it reduces gluten development (which keeps the cake tender) and it absorbs some moisture. If you're baking a cake and don't have cornstarch, you have two options.

The first is to replace the cornstarch with the same amount of flour. The cake will be slightly less tender but still edible. The second is to replace the cornstarch with baking soda mixed with an acid. For every 1 tablespoon of cornstarch, use 1/4 teaspoon of baking soda plus 1/2 teaspoon of an acid — buttermilk, plain yogurt, or white vinegar. This combination provides lift (the baking soda reacts with the acid) and keeps the cake tender. Mix the baking soda and acid together, then add them to your wet ingredients.

This method works best in recipes that already call for buttermilk or yogurt. If your recipe uses regular milk, add the acid separately and reduce the milk slightly to keep the liquid balance the same.

Xanthan gum for cold sauces and dressings

Xanthan gum is a thickener that works without heat, which makes it useful for salad dressings, cold sauces, and gravies you want to serve at room temperature. It's a powder made from fermented corn (though it's gluten-free and safe for people with corn allergies).

The catch: xanthan gum is much stronger than cornstarch. Use only 1/4 teaspoon of xanthan gum for every 1 tablespoon of cornstarch. Start with less and add more if needed, because too much creates a slimy texture. Whisk it into cold liquid first, then add to your sauce.

Xanthan gum is sold in the baking aisle or online. It costs more than cornstarch but a small container lasts a long time because you use so little.

Egg yolks for custards and cream sauces

If you're making a custard, pastry cream, or cream sauce, egg yolks thicken through heat without any starch. Whisk 1 or 2 egg yolks per cup of liquid, then slowly add hot liquid to the yolks while whisking constantly (this is called tempering). Pour the mixture back into the pot and cook over medium heat, stirring, until it thickens — usually 1 to 2 minutes.

The result is richer and silkier than a starch-thickened sauce, but it requires more attention. If the heat is too high, the eggs will scramble. This method doesn't work for savory gravies or Asian sauces, only for desserts and cream-based sauces.

Gelatin and agar for pie fillings and desserts

Gelatin sets a filling solid rather than thickening it to a pourable consistency. It works in fruit pies, cheesecakes, and mousse. Sprinkle powdered gelatin over cold water, let it sit for 5 minutes to bloom, then dissolve it in hot liquid. Pour into your filling and refrigerate until set.

Agar is a plant-based alternative to gelatin that sets at room temperature, which gelatin does not. It's useful if you're vegan or if you need a filling that won't melt. Use slightly less agar than gelatin — follow the package directions, as strength varies by brand.

Both gelatin and agar change the texture of the filling from pourable to solid, so they're not direct replacements for cornstarch in a traditional pie. They work best when you want a firm, sliceable filling.

Frequently Asked Questions

Can I use all-purpose flour instead of cornstarch in a pie filling?

Yes, but use twice as much flour and cook it longer. Mix 2 tablespoons of flour with a little cold liquid to make a paste, stir it into your filling, and simmer for 1 to 2 minutes. The filling will be slightly cloudier and less glossy than with cornstarch, but it will thicken.

What's the difference between cornstarch and potato starch?

They thicken at the same strength and produce nearly identical results. Potato starch is usually cheaper and easier to find. Cornstarch is slightly more neutral in flavor. For most home cooking, they're interchangeable.

Can I use cornstarch substitutes in gravy for Thanksgiving dinner?

Yes. Potato starch, arrowroot, and tapioca starch all work in gravy at a 1-to-1 ratio with cornstarch. Flour works but requires twice as much and must cook longer. Make a slurry with cold broth first to avoid lumps.

Does xanthan gum taste like anything?

No, xanthan gum is flavorless. It thickens without adding taste. Use it sparingly — too much creates a slimy, unpleasant texture. Start with 1/4 teaspoon per tablespoon of cornstarch and add more if needed.

What if I'm out of all these substitutes?

Flour is the most common pantry item that thickens. Use twice as much and cook it for at least 1 minute. If you have eggs, egg yolks work in cream sauces and custards. If you have gelatin or agar, they work in pie fillings and desserts, though the texture will be firmer.