All-purpose flour is a reliable cornstarch substitute for thickening soups, gravies, and sauces: use about 2 tablespoons of flour for every 1 tablespoon of cornstarch. This recipe makes a simple flour slurry for 2 cups of savory liquid, while the guide below explains when tapioca, arrowroot, potato starch, or another swap may work better.
Ingredients
- 2 cups (475 ml) broth or other savory liquid to thicken
- 2 tablespoons (16 g) all-purpose flour
- 3 tablespoons (45 ml) cold water
- ¼ teaspoon (1.5 g) fine salt, optional, depending on the broth
- ⅛ teaspoon (0.3 g) black pepper, optional
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 the slurry. Cold water helps disperse the flour before it reaches the hot liquid; adding dry flour directly to a simmering pot is much more likely to leave clumps.
- Bring the broth to a gentle simmer in a saucepan over medium heat. If you are thickening a sauce or soup already in progress, bring that liquid to a simmer instead. Reduce the heat if it is boiling vigorously.
- Whisk the slurry once more, then pour it into the simmering liquid in a thin stream while whisking continuously. Scrape around the bottom and corners of the pan so the flour does not settle and catch.
- Simmer gently for 3 to 5 minutes, stirring often, until the liquid thickens and the raw-flour smell has cooked away. It should coat a spoon lightly; it will thicken a little more as it cools. Stir in the optional salt and pepper, taste, and adjust the seasoning before serving.
Tips
- Use the right starting ratio. For most soups, gravies, and sauces, start with 2 tablespoons of all-purpose flour for each 1 tablespoon of cornstarch the recipe calls for. Flour thickens less strongly and makes a more opaque, less glossy result. If the sauce is still too thin after simmering, mix another teaspoon of flour with a tablespoon of cold water and add it gradually.
- Choose based on the dish. Flour is inexpensive and dependable for savory cooking, but it contains gluten and can make a sauce cloudy. For a clear fruit glaze or a glossy stir-fry sauce, tapioca starch, arrowroot, or potato starch is usually a closer match. Check package labels if you need to avoid gluten or another allergen.
- Keep starches from clumping. Mix powder with a cool liquid before adding it to hot food. For delicate starches such as arrowroot or potato starch, stir the slurry again immediately before pouring because it can settle quickly. Add it gradually rather than tipping the whole amount into the pan at once.
- Do not judge thickness while the pot is boiling hard. A sauce can look thinner when very hot and set more as it cools. Let it simmer gently, then pause briefly to assess it. Adding too much thickener at the start can leave gravy pasty or make a fruit filling gummy.
Serving Suggestions
This flour slurry is designed for a savory liquid, so use it to give chicken or vegetable gravy enough body to cling to mashed potatoes, roast vegetables, biscuits, or rice. It also works in a quick pan sauce: loosen browned bits from the pan with broth, then add the whisked slurry and simmer until the sauce coats the back of a spoon. Season after thickening because broth and pan drippings can already be salty.
For soup, remove a cup of broth from the pot, whisk the slurry into that cool or lukewarm portion, and stir it back into the simmering soup. This can be easier than making a separate bowl of slurry when the pot is crowded. Add it near the end of cooking, then allow several minutes of gentle simmering so the flour cooks through. It is especially suitable for creamy-style vegetable soups, bean soups, and chowder-like soups, although it will make the broth cloudy rather than transparent.
For a stir-fry or a fruit dessert, choose a different substitute from the options below instead of using this flour mixture. Flour gives a matte, opaque finish and can soften the clean, bright appearance of a clear sauce or pie filling. The best substitute is the one that fits the finished texture you want, not simply the one that is closest at hand.
Variations
Tapioca starch for pie filling and glossy sauces: Use about 2 tablespoons (16 g) tapioca starch for each 1 tablespoon (8 g) cornstarch, then adjust to the recipe and fruit’s juiciness. It creates a clear, shiny filling and tolerates freezing better than cornstarch in many fruit pies. Its texture can become slightly stretchy or sticky if you use too much, so measure carefully. Mix it with cold liquid or sugar before adding, and cook until the filling is visibly bubbling so the starch thickens fully.
Arrowroot for clear, delicate sauces: Use roughly the same amount of arrowroot powder as cornstarch, beginning with 1 tablespoon (8 g) for each 1 tablespoon (8 g) called for. Whisk it into cool water and stir it into hot liquid near the end of cooking. Arrowroot thickens quickly, but prolonged boiling can weaken its set; it may also turn stringy in some dairy-based sauces. It is a useful choice when you want a clear finish and do not need to keep the sauce at a long simmer.
Potato starch for quick thickening: Substitute about 1 tablespoon (12 g) potato starch for 1 tablespoon (8 g) cornstarch, starting with a little less if the dish is already thick. Stir it into cold water first and add it near the end, then heat just until the liquid thickens. Avoid a long, vigorous boil, which can make the texture pasty or cause it to thin again. Potato starch is not the same as potato flour; the two products behave differently, so check the label.
Rice flour for soups and stews: Use about 2 tablespoons (20 g) rice flour for each tablespoon of cornstarch, then simmer the dish for several minutes to cook out its powdery taste. Fine rice flour works better than a coarse grind, which can feel grainy. This option thickens with a more rustic, opaque texture, so it is better in stew or soup than in a clear glaze. Rice flour is naturally gluten-free, but avoid assuming a product is suitable for a strict dietary need unless its label confirms it.
For baking and coatings: A thickener swap in a saucepan is not automatically a one-for-one swap in a cake, cookie, or crisp coating. Cornstarch can make cookies more tender and can help create a light, crisp coating; all-purpose flour adds gluten-forming protein and may make the result firmer. For frying, potato starch or rice flour can provide a crisp coating, but the amount and browning will vary with the recipe. In cakes and cookies, it is usually safest to use a recipe written for the replacement rather than changing the starch without adjusting the other ingredients.
Storage and Reheating
Use the thickened sauce right away for the most even texture. If you have leftovers, transfer them to a covered, shallow container and refrigerate within 2 hours. Most cooked sauces and soups keep for 3 to 4 days in the refrigerator. Flour-thickened sauce may become thicker or develop a skin as it chills; stir it before reheating and add a splash of broth or water if needed.
Reheat leftovers on the stove over low to medium heat, stirring frequently, until steaming hot throughout. If using a microwave, cover loosely, heat in short intervals, and stir between intervals so the sauce warms evenly. Reheated leftovers should reach 165°F (74°C). Avoid repeatedly cooling and reheating the same pot; warm only the portion you plan to serve. Freezing is possible for many soups and gravies, but flour-thickened sauces can separate or turn grainy after thawing, so whisk while reheating and add liquid gradually to restore the consistency.
Frequently Asked Questions
What is the closest substitute for cornstarch?
There is no single best swap for every use. Tapioca, arrowroot, and potato starch can give a clear, glossy finish in sauces, while flour is widely available and works well in gravy and soup. For a basic savory sauce, use twice as much flour as cornstarch and simmer it for a few minutes. For a pie filling or clear glaze, tapioca or arrowroot is often a better fit.
Can I use flour instead of cornstarch in gravy?
Yes. Use about 2 tablespoons (16 g) all-purpose flour for every 1 tablespoon (8 g) cornstarch, whisk the flour with cold water, and add the slurry to simmering gravy. Cook it gently for 3 to 5 minutes to remove the raw-flour taste. The gravy will be more opaque and less shiny than a cornstarch-thickened gravy, but it will still coat meat, potatoes, and vegetables.
Can I substitute baking powder or baking soda?
No. Baking powder and baking soda are leavening agents, not reliable sauce thickeners. They can change flavor, acidity, browning, and how baked goods rise, and they will not provide the smooth thickening you expect from cornstarch. Choose a flour or starch that suits the dish instead.
What can I use if I need a gluten-free substitute?
For thickening, consider tapioca starch, arrowroot, or potato starch, and check the package for gluten-free labeling if cross-contact matters. Rice flour can also work, though it may produce a more opaque or slightly grainy result. Do not use ordinary all-purpose wheat flour as a gluten-free replacement.
Can I use the same substitute for a sauce and a pie?
Not always. Flour is practical in a gravy that will simmer, but it gives fruit filling a cloudy, sometimes heavy texture. Tapioca starch is often a better choice for a shiny pie filling, while arrowroot can suit a clear sauce that will not boil for long. Follow the recipe’s specific ratio where possible, since fruit moisture and cooking time affect how much thickener is needed.
Why did my sauce turn lumpy or thin?
Lumps usually form when dry flour or starch hits hot liquid before it is dispersed. Whisk it with cold water first, stir continuously as you add it, and avoid pouring it all in one spot. A sauce may stay thin if it has not simmered long enough, or if a delicate starch was boiled hard for too long. Give flour several minutes to cook; with arrowroot or potato starch, use gentle heat and stop once the liquid thickens.
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