How to Thicken Sauce Without Cornstarch

Cornstarch is a grain starch made from the endosperm of the corn kernel. It’s a go-to thickening agent for sauces and soups, but if you don’t have any on hand, consider the following methods for thickening:

1. 1. Reduce the sauce. Simmering your sauce over low heat will cause the water in the sauce to evaporate and the sauce to naturally thicken. Stir frequently to prevent the sauce from burning. Remove the sauce from the heat when it has reached its desired thickness; this may take significantly longer than a thickening agent. Remember to season your sauce after reducing it, not before; otherwise, the sauce might be too salty.
2. 2. Add egg yolks. Separate the egg whites from the yolks, and beat the yolks with a fork until smooth. To prevent the eggs from scrambling in the hot sauce, temper the mixture by adding a small amount of sauce to the egg yolks, then combining the mixture into the rest of the sauce. This method is ideal for making creamy sauces (such as pasta carbonara), salad dressings, puddings, ice cream, and custards.
3. 3. Prepare a roux. Use flour as a thickening agent by making a roux, a mixture of equal parts butter and flour. First, melt the butter over medium-low heat, then when the butter is bubbling, add in the flour. Cook the mixture until it’s light brown. Whisk the hot liquid into the roux, use two ounces of roux for every cup of liquid. This method is excellent for thick sauces, such as cheese sauces, cream sauces, pan sauces, and gravy—anything that can use the extra richness from the butter.
4. 4. Make a beurre manié. Another thickening method that uses flour and butter is a beurre manié, French for “kneaded butter.” Combine flour and softened butter into a thick paste, then divide the paste into small balls. As the sauce is simmering, add a ball of beurre manié to the sauce, adding more until the sauce reaches your desired consistency. You can make beurre manié ahead of time and store it in your refrigerator or freezer until you’re ready to use it—let it come to room temperature before using.
5. 5. Add pureed vegetables. You can puree veggies and use them to thicken a sauce or stew while also adding nutrients and flavor.
6. 6. Use another thickening agent. You can simply add a thickening agent to sauces, stews, stir-fry dishes, or gravies to thicken. In addition to cornstarch, popular thickeners include pantry staples like flour, gelatin, potato starch, and tapioca starch, among others.

If you do not have cornstarch in your pantry, the best cornstarch substitutes for thickening sauces include:

1. 1. All-purpose flour: You can thicken sauces with all-purpose wheat flour. For every tablespoon of cornstarch, use three tablespoons of flour. Combine raw flour with cold water in a small bowl to form a paste, then add it into the sauce as it's simmering. Cooking the flour in the sauce will remove the flour taste.
2. 2. Arrowroot powder: Arrowroot powder is a fine, gluten-free powder you can use in place of cornstarch as a thickening agent because it has a similar thickening power. Substitute arrowroot powder one-to-one for cornstarch. To prevent white clumps of powder in your sauce, mix the arrowroot with a bit of cold water in a small bowl to create a slurry before adding it to the sauce. It’s best to use arrowroot powder in sauces that contain acidic ingredients like citrus, vinegar, or tomato. Avoid using arrowroot powder in dairy-based sauces because it can make the sauce slimy.
3. 3. Gelatin: Gelatin is a popular thickening agent made from animal collagen. Most gelatin will need water to activate. Gelatin also tends to thicken as it cools, unlike cornstarch which thickens with heat, so gelatin is ideal for sauces that need to be consumed at a low temperature, such as pie fillings or fruit-based sauces.
4. 4. Glucomannan: Glucomannan is a fine powder made from the roots of the konjac plant. It is a soluble fiber and contains no carbs, making it a low-carb thickener that can increase the fiber content of your dish. Mix glucomannan with cold water before adding it to the sauce, and use small amounts.
5. 5. Ground flaxseeds: Like glucomannan, ground flaxseeds are also soluble fiber. The texture of ground flaxseeds is slightly gritty, so that it might give your sauce a mealy texture. To use, mix one tablespoon of ground flaxseeds with four tablespoons of water to substitute two tablespoons of cornstarch.
6. 6. Gums: You can also use vegetable gums, such as xanthan gum or guar gum, to thicken sauces. Xanthan gum and guar gum are very powerful, so use minimal amounts—too much can make the sauce slimy or unpleasantly chewy.
7. 7. Potato starch: You can use potato starch in place of cornstarch with a one-to-one ratio. Like tapioca starch, you shouldn't boil potato starch because it will lose its thickening power if overheated.
8. 8. Rice flour: Another good substitute for cornstarch is rice flour, a common gluten-free ingredient in many Asian dishes. First, you should dissolve rice flour in cold water to make a paste before adding it to sauces.
9. 9. Tapioca starch: Tapioca starch, also known as tapioca flour, is flour made from the cassava root. For every tablespoon of cornstarch, use two tablespoons of tapioca starch. Tapioca starch works well for thickening pan sauces that are already cooked. Avoid boiling tapioca starch as it can cause the sauce to become stringy.

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