Using a cornstarch slurry to thicken a sauce is pretty simple but the thickened sauce is much less stable than if you were to use a roux.  Don’t cook your sauce too long after thickening it with a cornstarch slurry and don’t reheat the sauce as both of those will cause the cornstarch to break down and the sauce will lose its consistency.

Using Your Cornstarch Slurry

By now you may be asking yourself what a slurry is, well, in order to use cornstarch as a thickening agent you must first add it to a bit of cold water and stir it up, this mixture is referred to as a cornstarch slurry.

To thicken your sauce simply make your constarch slurry then pour it in, if the sauce is hot you need to make sure you stir continually until the slurry is completely integrated.

If the sauce is hot the cornstarch slurry will begin thickening it almost immediately but you should continue to cook it on relatively low heat for about 5 minutes to remove any starchy flavor.

Note: You can use Arrowroot in place of cornstarch, the finished product will provide a slightly different look but it’s also much more expensive.