How To Make a Roux

One of the first tasks I was assigned as a line cook in a restaurant was to make a roux. During the summer after college, while figuring out what to do next, I spent hours working through Julia Child’s cookbooks, so the word roux had entered my vocabulary but the nuances were a bit fuzzy. Going on to work as a line cook and making countless roux-based sauces made it all second nature for me. I’ll walk you through everything about roux so you‘ll be a confident master of how to thicken sauces and stews. 

What Is a Roux?

For home cooks, the technique of making a roux—cooking flour and fat together to thicken a sauce—is essential for many of the dishes you’d like to create. Mac and cheese, gravy, pan sauces, gumbo, casseroles, and chicken pot pie are just a few of many examples of recipes that call for making a roux.

Don’t worry, there’s no real mystery to it. Fat (often butter, in the French tradition) and flour are cooked briefly together to form a paste. Then you whisk in liquid such as milk or stock to create a sauce or use the roux to thicken soups and stews.

Types of Roux

There’s not just one way to make a roux. How long you cook the roux before adding the liquid determines its color, flavor, and thickening power. The darker the roux, the less it will thicken a sauce.

• White (or Pale) Roux: The roux is cooked just until the mixture bubbles and is cooked through without coloring. It’s used for white sauce (such as béchamel) or to thicken soups or chowders.
• Blond Roux: This roux is cooked slightly longer, or until the mixture achieves a pale golden color. It adds a nutty flavor to a soup or sauce.
• Brown Roux: Even longer cooking will produce a deep brown roux that is used for brown sauces, such as Espagnole.
• Dark Brown Roux: A very dark roux is more useful for deep, earthy flavor than thickening, and it is the basis for many Cajun or Creole dishes like étouffée and gumbo.

The Fat

You can thicken a sauce by adding flour straight to liquid, without fat. This can often lead to lumps, and the fat acts as a buffer against this common dilemma. Fat in a roux also adds richness and gives the starch a vehicle to cook in so some of the raw flour taste cooks out. You get a more sophisticated sauce as a result.

• Butter: Most traditional roux for sauces (like béchamel, aka cream sauce) are butter-based. While restaurants often use clarified butter because it has no milk solids and thus a higher smoke point, a home cook can use regular, unsalted butter. 
• Vegetable Oil: If you prefer a more neutral flavor than butter, vegetable oils such as grapeseed or canola are a good choice. Roux made with vegetable oil can be cooked longer because it has a higher smoke point than butter.
• Animal Fats: Lard or rendered fat from pan-roasted meats will impart a much deeper, meatier flavor to the sauce. The most common way you might use animal fats is to make gravy for a roast, a roast chicken, or turkey.

The Fat to Flour Ratio

The traditional ratio of fat to flour by volume is one to one, e.g., one tablespoon of flour to one tablespoon of butter or other fat. More flour in the ratio means the roux becomes pasty and a little trickier to work with. More fat means a looser roux that incorporates into liquid more easily.

Is Gravy Made With Roux?

Yes! Using the fat from a roast or turkey as the basis for the roux is the easiest and most flavorful way to make gravy. Skim the fat from the pan, measure it, and then add an equal amount of flour. Cook the roux and whisk in stock.

Calculate the amount of gravy you want to make and work backward. For example, to make about 2 cups of gravy, you need 4 tablespoons of fat, 4 tablespoons of flour, and 2 cups of stock. Start with that formula, and then add additional stock to thin the gravy to the desired consistency.

Tips for Making Roux

While roux is not complicated, you still have to pay attention to a few details.

• If using butter, cut it into cubes before adding it to the saucepan and melt it over medium-low heat to keep it from burning. 
• Whisk in the flour and cook for at least 2 minutes after the mixture starts to bubble. This step keeps the sauce from having a floury taste. Watch carefully to prevent the butter solids from burning.
• Gradually add the liquid to the pan once the roux is cooked. Whisk the sauce vigorously and run the whisk around the bottom corners of the pan to keep lumps from forming. Once the liquid is smoothly incorporated, bring the sauce to a boil while stirring with a whisk or rubber spatula. Then simmer, stirring occasionally, for about 5 minutes.
• Don’t freak out if your sauce has a few lumps. The worst case scenario is that you strain it through a fine mesh strainer.
• For a thick sauce, start with less liquid or simmer the sauce until it reaches the desired consistency. Conversely, add more liquid to the sauce if you want to thin it.

Favorite Recipes Thickened With Roux

Creamy Macaroni and Cheese

Chicken Gumbo

Homemade Condensed Cream of Chicken Soup