How to make a roux perfectly — and what to do with it

There are certain things that become a part of a home cook's arsenal: a good roast chicken, some killer scrambled eggs, a perfect apple pie. Knowing how to make a roux should be at the top of this list. A roux is a simple two-ingredient mixture that can thicken sauces and stews. From a smooth, creamy béchamel for pot pies and macaroni and cheese — not to mention your Thanksgiving gravy — a roux is a technique to master and to love. It can be intimidating due to the ease with which it can be burned — and ruined — but it's nothing that a little practice can't resolve.   

So let's start with the basics steps to make a roux.

What is a roux?  

A roux is paste that is used as a thickener. It is simply flour cooked in fat, such as butter. As the proteins in the flour are heated, they expand and disperse evenly throughout the liquid that they are mixed with. Raw flour can be used as a thickening agent; however, cooking the flour first takes away the floury taste, gives the roux a nutty flavor, and creates a more even and smooth texture. 

To make a roux, first, a fat — butter, olive or vegetable oil, or rendered animal fat — is melted in a heavy-bottomed pan over medium heat. When it has been heated, an equal amount of flour is added. A 1:1 ratio generally works best for making a roux. The mixture must be whisked constantly, as it will burn very easily, until it has been cooked to the desired color. Then turn the heat down and let it continue to cook to soften the flavor of the flour. From here, you can add it as is to a stew or add whole milk to make a bechamel sauce. Take it to the next level by adding cheddar or Gruyère cheese for the ultimate silky cheese sauce. 

Types of roux

There are three major categories of roux that are dependent on the length of cooking. A white blonde roux, used commonly in light, creamy sauces like béchamel, has the shortest cooking time. The flour has been lightly browned but it is still very pale in color. Just beyond the white roux is the blonde roux. It is darker in color and can be recognized by the almost nutty smell that develops as the flours and fat continue to brown. The darkest roux is a brown roux which, having cooked the longest, has the deepest smell, flavor, and color. One thing to note is that the lighter a roux is, the more thickening power it has. That means you'll need more of a darker roux to thicken to the same degree as the same quantity of a lighter roux. A dark roux is a crucial component to many beloved Creole and Cajun dishes like gumbo, jambalaya, and etoufee.  

As a rule of thumb, a watched pot never boils but an unwatched roux will always burn.

The thing that's so tricky about making a roux is how many variables there are in the process. For a two-ingredient recipe, there are a shocking amount of outcomes. Heat, type of fat, timing, stirring utensil, even the movement of the cook's arm all contribute to the end result. That being said, there is really only one thing that matters when making a roux: patience. 

This really is one of those slow-and-steady-wins-the-race moments.

How to make a roux

Step 1:

Start with your fat. Usually, a recipe calling for a roux will tell you what sort of fat to use, as it will affect the flavor so greatly. If it doesn't, a good starting place is unsalted butter.

Step 2:

Heat the butter in a heavy pan over low heat. When the butter has melted and the foaming subsides, add the flour. The quantities should be the same. For example, if you use two tablespoons of butter, you'll want to use two tablespoons of flour, too. 

Step 3:

The moment the flour meets the butter, you'll need to start stirring, either with a whisk or a flat-edged wooden spoon. You will want a utensil that will allow you to keep the mixture moving, to prevent the roux from burning. 

At first, the mixture will be fairly liquid but keep stirring. As it continues to cook, it will thicken into a more paste-like substance. Soon, the color will begin to deepen. 

Step 4:

Keep stirring. You will be able to smell the flour cooking — a warm, pleasant, nutty scent. Keep stirring. The only thing you need to worry about is stirring. 

The amount of time it will take to cook is dependent on many things — your stove, the fat you use, the type of roux your recipe calls for. For instance, a white roux might only take a couple of minutes, whereas a dark roux will take much longer. My mother once took a cooking class down in New Orleans — the chef swore that the amount of time it takes to make a proper dark roux for a gumbo is equal to the amount of time it takes to drink an entire six-pack of beer. The important thing is to take your time. And did I mention, stir?

Step 5:

Once your roux is browned to your liking, add warm or room temperature stock or milk, continuing to whisk vigorously. It's important that the liquid and roux are similar temperatures. Otherwise, adding a very cold liquid to the very hot roux will cause it to get lumpy. And then voila, your sauce is ready!

Recipes that call for a roux 

Easy Béchamel Sauce (White Sauce) 

The only ingredients you need to make a classic white sauce, or béchamel sauce, are unsalted butter, flour, and milk. In order to achieve a super silky, homogeneous sauce, heat the milk before whisking it into the roux. Once it's fully incorporated and has thickened, you can use the bechamel as the base for macaroni and cheese, lasagna, a sauce for croque monsieur, and vegetable gratins.

Alton Brown's Shrimp Gumbo

To thicken this cajun and creole staple, add a roux! It's pure magic. This recipe calls for a dark roux, which means that it's cooked fully until the flour and butter have deepened to a dark brown hue.

Stovetop Mac and Cheese with Garlic Powder and White Pepper

This easy, peasy mac and cheese recipe uses a roux to thicken the sauce. A combination of provolone, asiago, and fontina cheeses are used because they're a little sweet, a little nutty, and super buttery.

Achiote Roux Brick

This roux spiced with coriander, cumin, allspice, cloves, annato seeds, garlic, and peppercorns was voted "Your Best Recipe Starring Butter!" You can add it to a vegetable curry, roasted vegetables, chicken or veggie tacos, or vegetable soup. Or try something else entirely . . . You may just be on to the next best thing!

Lasagna Bolognese

Both marinara sauce and bechamel sauce star in this classic Italian-American lasagna that will feed a hearty crowd. Instead of ricotta cheese, recipe developer Anna Francese Gass recommends mascarpone cheese, which is even richer and creamier for the ultimate decadent pasta dish.

Croque Madame Hot Dish 

The difference between a croque monsieur (aka a fancy ham and cheese sandwich) and a croque madame is the inclusion of a creamy bechamel sauce. This casserole recipe has a layer of the sauce on the bottom of the baking dish and another layer in the middle of the ham and cheese sandwiches.