How to Thicken a Sauce

There are hundreds of ways to thicken sauces, but only a handful are commonly used. All of them are uncomplicated and easy to do. In each case, though, you'll need to start with some sort of base liquid that you'd like to make a sauce out of.

Instructions

Difficulty: Moderately Easy

Things You’ll Need:

• All-purpose Flour
• Butter
• Cornstarches
• Vegetable Oils
• Wire Whisks

1. Thicken most broths for gravies with roux, a cooked mixture of flour and a cooking fat (see Related eHow on roux for more details). Roux needs to be cooked first, but gravies made with it are virtually lump-free. Many cream soups are also thickened this way.
2. Use a cornstarch slurry to thicken fruit and vegetable juices. To make a slurry, dissolve 1 tbsp. cornstarch or flour in 2 tbsp. ice water, then whisk the slurry into 1 c. of boiling liquid. Simmer the sauce at least 15 minutes to allow the starch to work. Cornstarch is commonly used to thicken stir-fries and many Asian dishes.
3. Use a cooked vegetable puree to make a rustic sauce. For example, sautéed onions that are braised with a pot roast can be strained out, pureed and whisked back in to the braising liquid to create a flavorful sauce with no added fat.

Tips & Warnings

• Most sauces benefit from some simmering before you thicken them. Simmering them slowly allows them to reduce, which means excess moisture will evaporate and what's left will be more concentrated in flavor. Sometimes this is enough to thicken a sauce on its own, particularly with cream sauces or marinara and other sauces made from pureed vegetables.
• Reducing sauces can be tricky, though, because the amount of salt and other seasonings will also concentrate, so make sure to purposefully underseason everything and correct it only at the very end.
• Butter is the best thickener to use on very powerfully flavored liquids such as wine and concentrated pan juices. Butter softens the powerful flavors and smooths out the texture. Whisk in partially softened cubes of butter over very low heat, tasting as you go, and serve these sauces in tiny amounts. Don't heat them, or they'll separate.