How To Thicken Sauce With Cornstarch

Use a Cornstarch Slurry to Thicken Gravy and Other Sauces

cornstarch mixed with water

Diana Chistruga / The Spruce Eats

Prep: 1 mins
Cook: 4 mins
Total: 5 mins
Servings: 2 to 6
Yield: 2 tablespoons slurry
Nutrition Facts (per serving)
10 Calories
0g Fat
2g Carbs
0g Protein
Show Full Nutrition Label Hide Full Nutrition Label
Nutrition Facts
Servings: 2 to 6
Amount per serving
Calories 10
% Daily Value*
Total Fat 0g 0%
Saturated Fat 0g 0%
Cholesterol 0mg 0%
Sodium 0mg 0%
Total Carbohydrate 2g 1%
Dietary Fiber 0g 0%
Total Sugars 0g
Protein 0g
Vitamin C 0mg 0%
Calcium 0mg 0%
Iron 0mg 0%
Potassium 0mg 0%
*The % Daily Value (DV) tells you how much a nutrient in a food serving contributes to a daily diet. 2,000 calories a day is used for general nutrition advice.
(Nutrition information is calculated using an ingredient database and should be considered an estimate.)

Cornstarch is a common thickening agent, but if you add it directly to the liquid you want to thicken, it will clump up. To thicken a sauce or soup with cornstarch, you first need to make a slurry, which is a mixture of equal parts cornstarch and liquid (usually water, stock or wine). It's important to make the slurry with cold liquid, and then add the slurry to the simmering sauce.

How Cornstarch Works

The cornstarch molecules are like little sponges. They soak up water and expand as they do so. The same thing happens with any starch. It's the same way rice, oatmeal, or polenta thickens and expands in volume when simmered.

How to Make a Cornstarch Slurry

Cornstarch imparts a glossy sheen to the liquids it thickens, so it tends to be used more in sweet sauces and pie fillings than in savory sauces and gravies. Still, it works really well, and it's easy to use. A general rule of thumb, is 1 tablespoon of cornstarch whisked with 1 tablespoon of cold liquid for every cup of liquid you are trying to thicken. Whisk the slurry into the hot, simmering liquid that you want to thicken.

We created a simple cornstarch slurry recipe to use for 2 cups liquid, but feel free to adjust ratios as needed.

How to Use Cornstarch Thickener

Uses range from everything from sauces, soups, gravies, and more. Cornstarch can be used to make a quick gravy sauce if your meat dish needs a little extra flavor. In that case, use chicken stock for your slurry instead of water. Once the slurry is made, add in any meat drippings or small bits from the pan.

Suppose you're making a stir-fry, and it's become watery—this often happens when your wok or pan isn't hot enough. You could let it reduce, but you'll just overcook your veggies. Instead, add a cornstarch slurry and all that extra liquid will thicken into a flavorful sauce.


  • 2 tablespoons cornstarch

  • 2 tablespoons water (or other liquid), cold

Steps to Make It

  1. Gather the ingredients.

  2. Whisk together the cornstarch and liquid in a small bowl until a smooth paste forms. This is the slurry.

  3. Whisk the slurry into the hot, simmering liquid that you want to thicken.

  4. Bring to a boil and simmer, stirring, until any starchy taste has been cooked away and the mixture is thickened to your liking, about 2 minutes. Don't cook longer, though, as the starch may break down and the liquid will thin out again.

What to Use Instead of Cornstarch

Something to remember when you're using cornstarch: If your sauce is quite acidic (like maybe it's tomato-based), the acid will cause cornstarch to lose some of its effectiveness as a thickener. In that case, you can substitute arrowroot or tapioca starch.

These two alternatives are also better options if what you're making is something you're planning to freeze because cornstarch can take on a spongy texture when frozen. Conversely, don't use arrowroot to thicken a cream or milk-based sauce as arrowroot combined with milk can be a bit slimy.