Cornstarch Substitute: Best Swaps and Ratios

A good all-purpose substitute for cornstarch is plain all-purpose flour: use 2 tablespoons (16 g) flour for every 1 tablespoon (8 g) cornstarch, and simmer it longer to cook away its raw taste. For a gluten-free swap with a similar glossy finish, use potato starch or tapioca starch in a 1:1 ratio; the simple flour slurry below shows how to thicken a cup of broth.

Ingredients

1 cup (240 ml) broth or stock, preferably low-sodium
2 tablespoons (16 g) all-purpose flour
2 tablespoons (30 ml) cold water
⅛ teaspoon (about 0.7 g) fine salt, optional; adjust to the saltiness of the broth

Instructions

Whisk the flour and cold water together in a small bowl until the mixture is smooth, with no dry pockets or lumps. This is a flour slurry. Cold water helps disperse the flour before it meets hot liquid; do not sprinkle dry flour directly into the broth.
Pour the broth into a small saucepan and bring it to a gentle simmer over medium heat, about 3 minutes. If using salt, wait to add it until you have tasted the finished sauce, since broth can already be salty.
Whisk the slurry again, then pour it slowly into the simmering broth while whisking continuously. Keep the liquid at a gentle simmer rather than a hard boil so the thickener cooks evenly and does not stick to the pan.
Simmer and whisk for 5 minutes, until the broth has thickened and no raw-flour taste remains. The sauce will thicken a little more as it cools. Taste, add salt if needed, and use it warm as a light gravy or sauce.

This small-batch recipe uses the common flour-to-cornstarch conversion: twice as much flour by volume. One tablespoon of cornstarch can thicken roughly one cup of liquid to a fairly pronounced, glossy consistency; two tablespoons of flour give a softer, more opaque finish. The exact result depends on the liquid, how much fat it contains, and how thick you want the final sauce, so treat the ratio as a starting point rather than a guarantee.

For a larger pot, multiply the ingredients proportionally. For example, to thicken 4 cups (950 ml) of broth with flour, whisk 8 tablespoons (64 g) flour with 8 tablespoons (120 ml) cold water, then add it gradually and simmer until the sauce tastes cooked through. If the sauce is still thinner than you want, mix another small slurry rather than adding dry flour or dumping in a large extra portion. If it becomes too thick, whisk in broth or water a tablespoon at a time.

Flour thickens through its starch, but it also contributes flavor and makes a sauce cloudy. That is welcome in many gravies, stews, and creamy soups, but it may not suit a clear fruit glaze or a shiny stir-fry sauce. For those, a pure starch such as tapioca, potato, or arrowroot is usually a closer match. The alternatives below are all useful, but they do not behave identically in every recipe.

Tips

Choose the swap for the result you want. Flour is inexpensive and easy to find, but it makes sauces opaque. Potato starch or tapioca starch gives a clearer, glossier finish and is generally used in the same amount as cornstarch. Check that a packaged product is labeled starch, not flour, because the two can behave differently.
Make a smooth cold slurry. Whisk any powdered thickener with cool water or another cool liquid before adding it to a hot pan. Start with about equal parts powder and liquid for a pourable slurry, then stir it into the sauce gradually. The slurry liquid is in addition to the recipe’s main liquid.
Adjust the heat and timing. Flour needs a few minutes of simmering to lose its raw cereal flavor. Tapioca and potato starch are better added near the end; prolonged vigorous boiling can make their texture less pleasant or weaken the thickening. Follow a recipe’s method when it specifies a particular starch.
Check labels for dietary needs. Wheat flour contains gluten, while cornstarch, arrowroot, tapioca, and potato starch are naturally gluten-free; packaged products can still have cross-contact, so check the label if that matters. Rice flour can also thicken, but it may leave a slightly grainier texture unless it is cooked thoroughly.

Serving Suggestions

Use the finished broth sauce as a quick gravy for roasted vegetables, mashed potatoes, biscuits, or a cooked meat dish. It also works as a mild thickener for a pot pie filling or a simple soup when a clear, glossy appearance is not important. Since broth varies in saltiness, taste before seasoning, especially if the sauce will be served with an already-seasoned main dish.

For a pan sauce, first remove cooked food from the pan and loosen the browned bits with broth. Measure or estimate the liquid, bring it to a simmer, then whisk in an appropriately scaled flour slurry. If the pan contains a lot of fat, spoon off the excess before thickening; too much fat can make the sauce feel greasy and can keep the flour from dispersing evenly. Serve the sauce promptly, while warm, because it may continue to thicken as it stands.

Variations

Potato starch: Use 1 tablespoon (about 10 g) potato starch for each 1 tablespoon (8 g) cornstarch as a practical starting ratio. Mix it with cold water and stir it into a hot sauce near the end of cooking. It can make a smooth, glossy sauce, but avoid boiling it hard for a long time because the texture can turn pasty or stringy.

Tapioca starch: Start with an equal amount by volume to the cornstarch being replaced. It is a useful choice for fruit fillings and sauces where a clear, shiny appearance is wanted. Whisk it into cold liquid first, add it near the end, and heat until the mixture thickens; excessive cooking can make it gummy. Tapioca flour and tapioca starch are commonly used as names for the same product in many stores.

Arrowroot: Substitute it in a 1:1 volume ratio and make a cold slurry. It can give a glossy finish and is often useful in acidic fruit sauces. Stir it in near the end and avoid a prolonged boil. In milk-based sauces, it may become slippery or stringy, so flour or another recipe-recommended thickener is often a better choice.

Rice flour or a roux: Rice flour is not as direct a swap; begin with about 2 tablespoons (20 g) rice flour for each tablespoon of cornstarch, whisk well, and allow enough simmering time for the texture to smooth out. For a richer, classic gravy, cook 2 tablespoons (28 g) butter with 2 tablespoons (16 g) all-purpose flour before gradually whisking in 1 cup (240 ml) broth. This roux method gives a deeper flavor than a cold slurry, but it is not gluten-free and takes a little more attention.

For soups and stews: If appearance is not important, a spoonful of instant potato flakes can thicken a pot gradually, though it changes the flavor and is not a precise cornstarch replacement. Stir in a small amount, wait a minute for it to absorb liquid, and add more only if needed. This is a flexible fix for a loose soup, not the best choice for a delicate dessert glaze or a smooth, clear sauce.

Storage and Reheating

Use the sauce right away for the smoothest texture. If you have leftovers, transfer them to a covered container and refrigerate within 2 hours of cooking. The sauce keeps for 3 to 4 days in the refrigerator. Flour-thickened sauce may set firmly when cold or develop a thin layer on top; that is usually a texture change rather than a reason to add more flour.

Reheat gently in a saucepan, stirring often and adding a splash of broth or water if it has become too thick. For food-safety guidance, USDA FSIS recommends reheating leftovers to 165°F (74°C); check with a food thermometer. A microwave also works: cover loosely, heat in short intervals, and stir between them so the sauce warms evenly. Do not leave the sauce at room temperature for more than 2 hours, and do not use home canning or room-temperature storage for it. Freezing is possible, but flour-thickened sauces can separate after thawing; whisk while reheating to improve the texture.

Frequently Asked Questions

What is the closest substitute for cornstarch?
For many cooked sauces, potato starch or tapioca starch is the closest match in thickening strength and glossy appearance; begin with the same amount as the cornstarch in the recipe. All-purpose flour is the easiest pantry substitute, but use about twice as much and simmer it for several minutes. The best choice depends on whether you need a clear finish, a gluten-free option, or simply a dependable gravy thickener.

How much flour replaces 1 tablespoon of cornstarch?
Use about 2 tablespoons (16 g) all-purpose flour for 1 tablespoon (8 g) cornstarch. Mix the flour with cool water before adding it to hot liquid, then simmer for several minutes to cook out the raw flavor. Because flour thickens less strongly and makes the liquid opaque, the finished result will not be exactly the same as a cornstarch-thickened sauce.

Can I add a substitute directly to a hot sauce?
It is safer to mix powdered flour or starch with cool liquid first. Adding dry powder straight to a hot pan can create lumps that are difficult to whisk out. Make a smooth slurry, stir it into simmering liquid in a thin stream, and give the sauce time to thicken before deciding whether it needs more.

What is the best gluten-free replacement for cornstarch?
Potato starch, tapioca starch, and arrowroot are common gluten-free alternatives, often used in a 1:1 ratio by volume. Their behavior differs: potato and tapioca can work well in glossy sauces, while arrowroot is less suited to long boiling or some dairy sauces. Read the package label if avoiding gluten, since manufacturing and cross-contact practices vary.

Can I use baking powder or baking soda instead?
No. Baking powder and baking soda are leaveners, not dependable sauce thickeners, and they can add an unwanted flavor or change how a recipe rises. Choose flour, potato starch, tapioca starch, arrowroot, or another recipe-appropriate thickener instead. For a soup or stew, you can also simmer it uncovered to evaporate some liquid, though that concentrates its flavor and salt as well.

Why is my sauce still thin after adding flour?
It may need more simmering time, or the initial flour amount may be too small for the volume of liquid. Keep it at a gentle simmer and stir for several minutes before adjusting. If it remains thin, whisk a little more flour into cold water in a separate bowl and add that slurry gradually. Avoid adding dry flour directly, and remember that a warm sauce may thicken further as it cools.

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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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