What is Roux?
Roux (pronounced “roo”) is a classic French mixture of cooked fat and flour used by chefs as a sauce/soup/stew thickener.
Traditionally equal parts fat and flour (by weight) are used, though if you’re making a roux from pan drippings/rendered fat you’ll likely have to eyeball it and just add flour, stirring, until a very thin paste/wet sand consistency has been reached. Bread flour is the most common choice, although you can use other varieties.
The Four Stages of Roux:
The longer a roux cooks, the more the starch granules are toasted and the darker it becomes. Toasting starch increases its nutty flavor, but decreases its thickening ability.
White Roux: Cooked over medium heat. Neutral flavor and strong thickening power.
Blond Roux: Cooked to blond/light brown over medium heat. Slightly stronger, nutty flavor with slightly weaker thickening power.
Brown Roux: Cooked over low heat to a darker brown color…think brown gravy. 1/3rd the thickening power of white roux, but with a rich, toasty flavor. For very dark brown roux, you should first toast the dry flour in the oven until dark brown, then make the roux.
Black Roux: Black roux is also known as burnt roux or ruined roux. Time to throw it out. It won’t thicken your dish, and will instead impart a nasty bitter flavor and oil-slick like consistency.
Here’s the traditional from-scratch roux method, using butter:
1. Melt butter in saucepan on low.
2. Once the butter is melted, add the flour.
3. Stir over medium-low heat. The consistency should be like wet sand. If drier, then you need more butter. If moister, then you need more flour.
4. Cook for a few minutes (just until the mixture doesn’t taste like flour…it should smell a little like baking pie crust) for white roux.
5a. For blond roux, keep cooking, stirring occasionally, until the mixture becomes a blond/light brown color.
5b. For brown roux, reduce the heat to low and slowly cook until the mixture is a darker brown.
6. Either add your roux to the liquid being thickened or add that liquid to your roux.
a. If using a hot liquid, stir constantly while adding one to the other, to make sure the roux evenly distributes rather than clumping.
b. If it’s a cold liquid, stir in some of the liquid, whisking until the roux is completely integrated, then add the rest, or (if adding to a liquid in another pot) remove some of the liquid, stir in the roux, and return it to the pot.
7. Bring the mixture just to a boil, then reduce to a simmer. Simmer for 10 to 20 minutes (until thickened).
How Much Roux to Use:
Use about 1 parts (by weight) white/blond roux to thicken 10 parts sauce in order to reach a consistency that will coat the back of a spoon. You’ll need to use more brown roux (perhaps as much as 1 part roux to 3 parts sauce) to achieve the same consistency.