Yes, cornstarch works as a substitute for potato starch in most recipes, but the results differ slightly

Cornstarch and potato starch are both thickeners made from plant starches, so they perform the same basic job in cooking. You can swap one for the other in a 1:1 ratio by weight or volume in most recipes. The main difference is texture: cornstarch produces a glossier, more translucent finish, while potato starch creates a softer, more opaque result. Cornstarch also sets up faster as it cools.

The swap works best in gravies, sauces, soups, and pie fillings. It works less well in delicate baked goods where potato starch's neutral flavor and tender crumb are important — cornstarch can make cakes and cookies slightly tougher. For frying or breading, cornstarch gives a crispier crust than potato starch does.

Key Takeaways

  • Cornstarch and potato starch can be substituted 1:1 in sauces, gravies, and pie fillings without changing the amount.
  • Cornstarch produces a glossier, more translucent sauce; potato starch produces a softer, cloudier one.
  • Cornstarch sets faster as it cools and creates a crispier coating when used for frying.
  • In baked goods, cornstarch may make the texture slightly tougher than potato starch would.
  • Both starches thicken at the same temperature and break down if overheated or stirred too vigorously.

How the two starches behave differently when heated

Both starches thicken liquid by absorbing water and swelling, but they swell at slightly different rates and to different degrees. Potato starch swells more fully and creates a softer, more delicate gel. Cornstarch swells less but holds its structure longer, which is why cornstarch sauces feel slicker on the tongue and hold their shape better when cooled.

Temperature matters for both. Potato starch thickens around 140°F (60°C), while cornstarch thickens around 144°F (62°C) — close enough that you won't notice the difference in practice. However, both break down if the mixture boils hard for more than a few minutes. If you're making a sauce that will simmer, cornstarch is slightly more forgiving because it holds together longer under heat.

When cornstarch works well as a replacement

Cornstarch is the better choice when you want a glossy, clear sauce. Gravies, Asian stir-fry sauces, fruit pie fillings, and glazes all benefit from cornstarch's translucent finish. It also works well for coating foods before frying — the crust will be crispier and more golden than it would be with potato starch.

Cornstarch is also cheaper and more widely available than potato starch in most grocery stores. If you're out of potato starch and need a thickener right away, cornstarch is the easiest substitute to find. It stores well in a cool, dry cabinet for years without losing potency.

When potato starch is better and cornstarch falls short

Potato starch is the preferred choice in tender cakes, cookies, and pastries because it produces a softer crumb. If you substitute cornstarch in these recipes, the baked good may feel slightly drier or tougher. This matters most in delicate items like sponge cakes, chiffon cakes, or shortbread cookies where texture is the whole point.

Potato starch also has a more neutral flavor, while cornstarch can leave a faint starchy taste if not cooked long enough. In recipes where the sauce is served cold or barely heated — like a fruit coulis or a cold pudding — potato starch is less likely to taste raw.

How to substitute cornstarch for potato starch in sauces and gravies

Use the same amount of cornstarch as you would potato starch. If a recipe calls for 1 tablespoon of potato starch, use 1 tablespoon of cornstarch. Mix the cornstarch with a small amount of cold water or broth to make a slurry before adding it to the hot liquid — this prevents lumps. Stir the slurry into your sauce or gravy while it simmers gently.

Let the mixture bubble for 1 to 2 minutes after adding cornstarch so it thickens fully. The sauce will look thin at first, then suddenly thicken as it heats. Stop stirring once it reaches the thickness you want, because over-stirring can break down the starch and make the sauce thin again. If you're making a sauce that will sit for a while, cornstarch will hold the thickness better than potato starch as it cools.

Substituting cornstarch in baked goods

If you must use cornstarch instead of potato starch in a cake or cookie recipe, use slightly less — about 0.75 tablespoon of cornstarch for every 1 tablespoon of potato starch called for. This accounts for cornstarch's slightly stronger thickening power. The texture will still be a bit firmer than the original recipe intended, but the difference will be less noticeable.

This substitution works better in recipes where potato starch is one of several dry ingredients rather than the main thickener. In a flour blend for pastry or a coating for fried chicken, the difference is minor. In a recipe where potato starch is the primary thickener — like a pudding or custard — stick with potato starch if you have it.

Other starches that work as substitutes

If you don't have cornstarch or potato starch, tapioca starch works the same way as potato starch and can be substituted 1:1. Arrowroot powder is another option, though it thickens slightly faster and produces a clearer sauce. All-purpose flour can thicken sauces but requires twice as much by weight and produces a cloudier, less glossy result.

Rice flour and sweet rice flour both work as thickeners but produce different textures — rice flour makes a grainy sauce, while sweet rice flour (also called mochiko) creates a very smooth, sticky result. For baking, cake flour or pastry flour can replace potato starch in a pinch, though the texture will be different.

Frequently Asked Questions

Will cornstarch make my sauce taste different?

Cornstarch has a faint starchy taste if it is not cooked long enough. Potato starch is more neutral. If your sauce simmers for at least a minute after the cornstarch is added, the taste difference will be barely noticeable. Cold sauces made with cornstarch are more likely to taste slightly starchy.

Can I use cornstarch in a recipe that calls for potato starch if the recipe is already cooked?

Yes. If you are thickening a sauce or gravy that is already hot, cornstarch works just as well as potato starch. Mix it with cold water first to avoid lumps, then stir it in and let it bubble for a minute. The result will be glossier than it would be with potato starch, but the thickness will be the same.

Does cornstarch work for frying like potato starch does?

Yes, and cornstarch actually produces a crispier crust. Both starches create a coating that fries up golden and crunchy. Cornstarch gives a slightly more delicate, shatterier crust, while potato starch produces a tougher, chewier coating. For fried chicken or tempura, cornstarch is often preferred.

What happens if I use too much cornstarch?

Too much cornstarch makes a sauce gluey and unpleasant to eat. Start with the amount the recipe calls for, then add more if needed. If you overshoot, thin the sauce with a little water or broth and reheat it gently. Cornstarch sauces that are too thick can sometimes be thinned by whisking in more liquid and heating again.

Can I store cornstarch and potato starch the same way?

Yes. Both keep in a cool, dry cabinet for years. Store them in airtight containers away from moisture and heat. Cornstarch is slightly more prone to clumping in humid conditions, so a sealed container works better for cornstarch than for potato starch.