How to Use and Make a Cornstarch Slurry
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A Cornstarch Slurry is a paste-like mixture of cornstarch and water used to thicken sauces, soups and stews.

Culinary Uses

Cornstarch thickens much more effectively than wheat flour and can easily seize up your fat based sauce (cream, butter, etc.), if you are not careful. With a water or wine-based sauces, you have more flexibility.

The general rule of thumb for thickening a fat-based sauce with cornstarch slurry is the same as for using a roux. Use roughly 2 oz. (57g) of Cornstarch Slurry for each pint (.47L) of sauce, that you are thickening.

With a water-based sauce, the thickening power of a Cornstarch Slurry is roughly 25% less. With an acid-based sauce (wine, vinegar, some juices) it is about half.

To make a Cornstarch Slurry, dissolve 1 tbsp Cornstarch or Flour in 2 tbsp of COLD water. Next, whisk the slurry into 1 cup of boiling liquid. The difference in temperature is important to reduce the likelihood of lumps. The right proportions and temperatures should yield a consistency similar to heavy cream.

Simmer the sauce below 200°F (93° C) at least 5 minutes and up to 15 minutes.  Keeping the liquid at just below a boil allows the cornstarch to thicken to its full thickening potential and also allows the cloudy appearance to clear which restores the sheen of the product being thickened.

In addition to restoring the sheen, simmering the product allows for any starchy taste to dissipate. Simmer the sauce for up to 5 minutes to allow the starch to work. If the sauce is overheated or over-stirred, it will begin to breakdown and lose thickening power.

At temperatures above 200°F (93°C), the enlarged starch molecules start to shrink and as they deflate, the sauce thins. Don’t let cornstarch thickened sauces boil!

Smart Kitchen covers how to use a Cornstarch Slurry in Exercise 8: Stocks, Sauces & Soups Basics, Topic 3: SaucesExercise 10: Using Cornstarch.

Gluten Free


Low Fat


Low Calorie