Be sure to use cold water, since warm or hot water will cause the flour to clump together. If you want a thicker sauce, add a little more flour. Use less flour for a thinner sauce.

Make sure the slurry is thoroughly mixed into the sauce to create an even thickness.

The sauce will thicken a little more after it cools, so aim for getting it just shy of how thick you want it. You may need to experiment a bit to achieve the texture you want.

Allowing the sauce to reach a full boil after adding the slurry can also help cook off the flour flavor. [6] X Research source Take care not to let your sauce burn, however!

Butter, for a rich and creamy flavor. This is a good choice for cream-based sauces, like bechamel or alfredo. Animal fat, such as bacon or pork drippings. This will impart a meaty or sausage-like flavor, so choose this option for gumbos and other Creole dishes. Vegetable oil. This is the most neutral option, flavor-wise. It’s also less likely to burn than butter-based roux and is a vegan-friendly choice.

If you’re using a hard fat, like butter, melt it in the pan first and then stir the butter in.

You can ensure even cooking by stirring in a figure-8 pattern. [10] X Research source

Cook for 3-5 minutes for a light roux, which is good for sauces like bechamel or white gravy. [12] X Research source A light roux should be cooked enough to lose the characteristic raw flour taste and smell, but not long enough that it begins to brown. For brown roux, cook for 6-7 minutes. This is an ideal roux for brown gravy. [13] X Research source If you want dark roux, let your mixture cook for 8-15 minutes. This is a good option for Cajun and Creole sauces. [14] X Research source

If you add the roux to a cooler sauce while it is still bubbling hot, it will break apart and form clumps. As a general rule, it’s best to combine roux and the rest of your sauce when they are at similar temperatures. For example, if haven’t started heating your sauce yet, add the roux while both are cold or lukewarm.

During the simmering process, fat or oil may rise to the top of the sauce. Use a spoon to skim it off.