For most sauces and fillings, potato starch, tapioca starch, and arrowroot can replace cornstarch in roughly equal amounts; all-purpose flour usually takes about twice as much. The best choice depends on whether you are thickening a hot sauce, baking a pie, or coating food for frying, so this guide gives practical ratios and shows how to use them in a small batch of sauce.
Ingredients
- 1 cup (240 ml) broth or water, for the example sauce
- Choose one thickener for each 1 cup (240 ml) of liquid: 1 tablespoon (8 g) potato starch, 1 tablespoon (8 g) tapioca starch, or 1 tablespoon (8 g) arrowroot powder
- Alternatively, use 2 tablespoons (16 g) all-purpose flour or 2 tablespoons (20 g) rice flour per 1 cup (240 ml) liquid
- For a quick, rustic sauce, use 1 tablespoon (about 5 g) plain instant potato flakes per 1 cup (240 ml) liquid; add a little more only if needed
- For a custard-style preparation only, use 1 egg yolk (about 18 g) per 1 cup (240 ml) liquid; this is not a general-purpose thickener
- Optional: 1/8 teaspoon (about 0.4 g) xanthan gum per 1 cup (240 ml) liquid, for gluten-free sauces; start small because it thickens quickly
- Salt and other seasonings, to taste
Instructions
- Choose the substitute for the job. For a clear, glossy sauce, select potato starch, tapioca starch, or arrowroot. For gravy, soup, or a filling that can cook for several minutes, all-purpose flour is an accessible option. Rice flour suits some batters and fillings, while potato flakes are best when a slightly opaque, potato-flavored result is acceptable. The quantities above are starting ratios for one cup of liquid, not ingredients to combine.
- Make a smooth slurry when using a starch. In a small bowl, whisk your chosen starch with 1 tablespoon (15 ml) of cold water until no dry pockets remain. This water is separate from the cup of broth or water in the ingredient list. Do not stir dry starch straight into hot liquid: it can clump before it disperses. For flour, whisk it with 2 tablespoons (30 ml) cold water, or make a roux by cooking it with an equal amount of fat before adding liquid.
- Warm the liquid. Bring the cup of broth or water to a gentle simmer in a small saucepan over medium heat, stirring occasionally. If you are adapting another dish, follow that recipe’s directions for heating its liquid and add the substitute at the stage described below. Season the example sauce lightly; concentrated broth may already be salty.
- Whisk in the thickener. For potato starch, tapioca, or arrowroot, lower the heat and slowly pour in the slurry while whisking. Cook just until the sauce thickens, usually 30 to 90 seconds. Avoid a prolonged, vigorous boil: some starches can thin or turn stringy when overheated. For flour, whisk in the slurry and simmer gently for 3 to 5 minutes to cook away the raw-flour taste. Stir in potato flakes a little at a time and allow about 1 minute for them to absorb liquid before judging the texture.
- Use egg yolk only in an appropriate recipe. Whisk the yolk in a bowl, then gradually whisk in several spoonfuls of the hot liquid to temper it. Slowly return that mixture to the pan over low heat, stirring constantly until it thickens; do not let it boil. Egg-thickened sauces are richer and less clear than starch-thickened ones. If the dish is an egg-based preparation, cook it to 160°F (71°C); USDA FSIS identifies this as the safe minimum internal temperature for egg dishes.
- Check the finished consistency. Remove the pan from the heat once the sauce coats a spoon. It will usually thicken a little more as it stands. If it is too thin, mix a small additional amount of the same starch with cold water and whisk it in; if too thick, loosen it with broth or water, a tablespoon at a time. When replacing cornstarch in a larger recipe, multiply the ratio by the volume of liquid being thickened and adjust gradually.
Tips
- Match the starch to the finish. Arrowroot and tapioca can give sauces a shiny, slightly translucent look; potato starch also thickens quickly. Flour produces a more opaque, softer finish. If appearance matters, try a small amount before committing the entire dish.
- Keep heat in mind. Flour needs a few minutes of simmering, but several starch slurries need only brief heating. Arrowroot is especially prone to losing its thickening power if boiled hard or held hot for a long time, so add it near the end and serve promptly.
- Do not swap blindly in baking. Cornstarch may soften the texture of cakes, cookies, or pastry as part of a measured formula, rather than simply thicken liquid. Replacing it with an equal volume of flour can make baked goods heavier. Use a recipe-specific substitution when the cornstarch is part of the dough or batter itself.
- Make small adjustments. Different brands and recipes vary, and a sauce may thicken further as it cools. Start with the listed ratio, wait briefly, then add more only if necessary. A tiny amount of xanthan gum can make a sauce slick or gummy if overused, so measure carefully.
Serving Suggestions
Use the guide’s ratios to thicken pan gravy, a quick broth sauce, fruit pie filling, or the liquid in a stir-fry. For gravy or a cream sauce, flour is a familiar choice when a gently simmered finish is welcome. For a glossy stir-fry sauce, potato starch or tapioca is often more suitable, but stir the slurry again just before adding it because starch settles in the bowl.
For fruit fillings, stir the selected thickener with sugar or another dry ingredient before mixing it with juicy fruit if the recipe allows; this helps distribute it evenly. For deep-frying or shallow-frying, use potato starch, tapioca starch, or rice flour as a coating rather than expecting a sauce-thickening ratio to work. Coat the food lightly and fry according to the recipe; the result will differ in crispness from a cornstarch coating.
Variations
For gluten-free thickening: Choose potato starch, tapioca starch, arrowroot, rice flour, or a small measured amount of xanthan gum. Check product labels if avoiding gluten strictly, since manufacturing and packaged blends can vary. These options do not all behave alike: rice flour is more opaque, and xanthan gum is concentrated enough that excess can create a slippery texture.
For a classic roux: Cook 2 tablespoons (16 g) all-purpose flour with 2 tablespoons (28 g) butter or oil over medium-low heat, stirring, for 2 to 3 minutes. Gradually whisk in 1 cup (240 ml) broth. Simmer for another 3 to 5 minutes, until smooth and thickened. A darker roux has a toasted flavor but less thickening power, so it may not match the amount of cornstarch in a recipe.
For custards and delicate sauces: Egg yolks can provide richness and body, but they are not a direct, neutral replacement for cornstarch. Use them only when the dish’s flavor and method suit eggs, temper them with hot liquid, and avoid boiling. For a neutral fruit glaze or stir-fry sauce, choose a starch instead.
For a quick pantry option: Instant potato flakes can thicken soups and stews when their mild potato flavor fits. Stir in a small amount, let it hydrate, and assess the texture before adding more. They can make a sauce cloudy and are not the best choice for a clear glaze or a delicate dessert filling.
Storage and Reheating
For the example sauce, cool leftovers promptly and refrigerate them in a covered container within 2 hours. Use within 3 to 4 days. A thickened sauce may set more firmly in the refrigerator, and some starch-based sauces can separate or lose their original texture after chilling; that is a quality change rather than a reason to leave the sauce at room temperature.
Reheat gently in a saucepan over low to medium-low heat, stirring often. Add a splash of broth or water if it has become too thick. If the sauce contains meat, poultry, seafood, or eggs, reheat leftovers to 165°F (74°C), checking with a food thermometer. Avoid repeated cooling and reheating; warm only the amount you plan to serve. Freeze only if the specific dish tolerates it, since starch-thickened sauces can become grainy or separate after thawing.
Frequently Asked Questions
What is the closest substitute for cornstarch?
For many cooked sauces, potato starch is a useful starting point at about a 1:1 ratio by volume. Tapioca starch and arrowroot can also often replace cornstarch in equal amounts, though their texture and tolerance for heat differ. Start with the quantity in the recipe, then adjust after the sauce has briefly thickened.
Can I use flour instead of cornstarch?
Usually, yes, when thickening gravy, soup, or a cooked filling. Begin with about twice as much flour as cornstarch, disperse it in cold liquid or cook it into a roux, and simmer it for several minutes so the raw-flour taste cooks off. Flour makes the result more opaque and less glossy, and it is not a reliable one-for-one substitute in baking formulas.
Can I use baking powder or baking soda?
No. They are leavening agents, not dependable thickening substitutes, and using enough to thicken a sauce would affect its flavor and how it cooks. Choose a starch, flour, or another thickener suited to the dish instead.
Can I use arrowroot in a dairy sauce?
It can thicken some dairy-based sauces, but its texture may become less pleasant or slightly slimy, especially with prolonged heating. If you use it, add a well-mixed slurry near the end and avoid boiling. Flour or a recipe-designed roux is often a more dependable option for a sauce that will simmer or be reheated.
How do I substitute cornstarch for frying?
Use a coating ingredient, not the sauce ratios in this guide. Potato starch, tapioca starch, and rice flour can each produce a crisp coating, with results that vary by food and batter. Keep the coating light, follow the recipe’s frying temperature and timing, and do not assume that flour will give the same crisp finish.
Can I use the same substitute in every recipe?
No. A sauce, fruit filling, custard, and cake rely on different textures and cooking conditions. Flour is suitable for a simmered gravy but may weigh down a cake; arrowroot can work in a quick glaze but may weaken with extended boiling. Identify what the cornstarch is doing in the recipe, then choose an alternative that suits that job.
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