How to Make a Cornstarch Slurry

Here’s how to make a cornstarch slurry! Use this mixture to thicken sauces, soups, stews and more to a glossy consistency.

Want to thicken a sauce or stew? Cornstarch is the answer. That fine white powder is the ultimate culinary shape shifter. It gives watery sauces a luxuriously glossy sheen, and it gives tofu and chicken and ultra-crisp exterior. But before start: remember that you can’t simply sprinkle a bit of the white powder into your dish on its own. You’ll need this special step: a cornstarch slurry.

What’s a cornstarch slurry?

A cornstarch slurry is a mix of cornstarch and water (or another room temperature liquid). If dry cornstarch is added directly to a dish, it clumps up. The ratio of cornstarch to water is typically equal parts cornstarch and liquid.

Cornstarch must be heated to around 203°F for the thickening to occur. This is the temperature where “starch gelatinization” happens: the process where the the particles of cornstarch absorb water. So in order to be activated, the cornstarch slurry should be heated once it’s added to the dish.

When to make a cornstarch slurry? Use it to thicken stir fry sauces, soups, stews, gravies, fruit sauces, compotes, and other sauces where you want a thick, glossy body.

Cornstarch slurry

How to make a cornstarch slurry: basic steps

Ready to thicken your sauce? Here are the basic steps to a cornstarch slurry (or jump to the recipe below):

  • Mix 1 tablespoon cornstarch with 1 ½ tablespoons water. This amount of cornstarch should create a moderate amount of thickening, but this depends upon the quantity of liquid and exactly what you’re making. Start with 1 tablespoon, then add more as necessary depending on your recipe.
  • Pour the slurry into the heated dish (sauce, soup, stew, etc). You can also start with it cold and heat it along with the full recipe.
  • Stir constantly as it thickens. Cornstarch can still clump up if you don’t stir. Continue to stir as the sauce thickens. If it’s not thick enough, add another ½ or 1 tablespoon mixed cornstarch slurry and continue to stir.
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Alternative to cornstarch: arrowroot

Don’t want to use cornstarch? A great substitute is arrowroot starch, aka arrowroot powder. It’s the starch extracted from the arrowroot plant, and often used in gluten-free baking to bring a light texture to baked goods. It’s a great substitute for cornstarch that works for people with corn allergies, and it provides that nice glossy shine just like cornstarch. Replace arrowroot starch 1 for 1 with cornstarch.

You can also make a flour slurry in the same way as a cornstarch slurry. However, flour doesn’t thicken in the same way: it’s not as powerful of a thickener and the sauce doesn’t get as glossy. So we recommend arrowroot starch as the best substitute.

Recipes with cornstarch

Want a few real life examples? Here are a few recipes that use the concept of a cornstarch slurry:

This cornstarch slurry is…

Vegetarian, vegan, plant-based, dairy-free and gluten-free.


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Here’s how to make a cornstarch slurry! Use this mixture to thicken sauces, soups, stews and more to a glossy consistency.

  • 1 tablespoon cornstarch
  • 1 ½ tablespoons water (or stock)

  • Category: Sauce
  • Method: Stirred
  • Cuisine: N/A
  • Diet: Vegan

Keywords: Cornstarch slurry