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How to Make Roux and Use It to Thicken Soups and Sauces

A classic thickening agent for soups and sauces, roux (pronounced "roo") gives dishes silky-smooth body and a nutty flavor. It's an essential building block of dishes that range from macaroni and cheese to gumbo. How to make a roux is something every cook should know, and easier than you might think. Let's take a look!

 

Roux Overview

Roux is made by cooking equal parts flour and fat together until the raw flavor of the flour cooks out and the roux has achieved the desired color. Butter is the most commonly used fat, but you can also make roux with oil, bacon grease, or other rendered fats.

There are four varieties of roux: white, blond, brown, and dark brown. The different colors are a result of how long the roux is cooked; white is cooked for the shortest time, while dark brown cooks the longest. White and blond roux are the most common, used to thicken sauces, soups, and chowders. Brown and dark brown roux have more flavor, but less thickening power than white or blond roux. Dark roux are primarily used in Cajun and Creole dishes, most notably gumbo and jambalaya.

If you're cooking and storing a batch of roux for future use, use clarified butter as it will harden when refrigerated, trapping the flour in suspension. This suspension helps to prevent lumps when the roux is whisked into a sauce or soup. Having a well-made roux on hand will make it easy to use this marvelous thickener in everyday cooking.

How to Make Roux

Roux takes just a few minutes to make. Whether you are making just enough for a single dish, or a batch to divide and freeze for later, the proportions of ingredients are the same: 1 part oil or fat and 1 part all-purpose flour, by weight. If you have a kitchen scale, this is easy to measure. If you do not have a kitchen scale, use measuring cups or spoons to measure 1 part oil or fat and 1-3/4 parts all-purpose flour.

We'll explain how to make a small batch.

Begin by heating 2 tablespoons oil or fat in a saucepan over medium heat until a pinch of flour sprinkled into the oil will just begin to bubble.

Making a Roux

Photo by Meredtih

Then, whisk in 3-1/2 tablespoons of flour to form a thick paste the consistency of cake frosting. Continue whisking as the roux gently bubbles and cooks to the shade desired. Do not allow the roux to bubble too vigorously, or it will burn rather than brown.

Making a Roux

Photo by Meredith

Four Stages of Roux

roux-CookingStages

From left to right: white roux, blond roux, brown roux, dark brown roux | Photo by Allrecipes

The white stage is reached once the flour loses its raw smell, after about 5 minutes of cooking and stirring. Although slightly grainy in texture, it is much smoother than it was at the beginning. The mixture is bubbling vigorously and the color is a little paler than when the clarified butter and flour were first combined.

The blond stage is reached after about 20 minutes of continuous cooking and stirring. The bubbles are beginning to slow, and the aroma has taken on nuances of popcorn or toasted bread. The roux is now tan colored, very smooth, and thinner than it was at the white stage.

The brown stage is reached after approximately 35 minutes of cooking and stirring. It be a peanut butter-brown color and its aroma is more pronounced and sharper than the nutty nuances of blond roux. The roux is now thinner, and the bubbling has slowed even more.

The dark brown stage is reached after about 45 minutes of cooking and stirring. It is the color of melted milk chocolate. Its aroma will also mellow from the strong, roasted flavor of brown roux and will actually smell a little like chocolate. The roux is no longer bubbling, and is very thin.

Adding Liquid

After cooking roux, you'll usually add a liquid ingredient to make a sauce (milk added to white roux, for example, makes white sauce).

To ensure lump-free thickening when making sauces, the liquid ingredient should be cold or room temperature, and slowly whisked into the hot roux. Do this by adding the liquid a little at a time, whisking until smooth between each addition, until the roux forms a thin paste, then whisking in the remaining liquid and bringing the mixture to a simmer. Cold or room temperature roux is simply whisked into a simmering soup or sauce until it dissolves. These methods ensure the roux is incorporated slowly and the mixture will not form lumps.

Roux begins to thicken soon after it is combined with a liquid, but it must be simmered for 10 to 20 minutes in order to reach its full flavor and thickening potential. This additional cooking time allows the flour to soften and absorb the liquid, resulting in a silky smooth soup or sauce. If the simmering time is too short, the flour in the roux will remain grainy.

The Right Color Roux for Your Recipe

White Roux

White roux is cooked for about 5 minutes, just until the flour has lost its raw smell, but before any golden color or toasted aroma develops. This roux is used to thicken chowders and milk-based sauces. Classic macaroni and cheese, tuna noodle casserole, and New England clam chowder are all based on milk thickened with a white roux.

Baked Potato Soup I

Baked Potato Soup I | Photo by Christine Boutwell Mita

Blond Roux

Blond, or golden roux, is cooked approximately 20 minutes to a light, golden-brown shade with an aroma resembling popcorn or toasted bread. This is the most commonly-used roux, desired for the richness and a slight nuttiness it provides along with its excellent thickening power. Blond roux is a good, general-purpose roux to keep on hand for thickening gravy, sauces, soups, and stews.

Garden Fresh Tomato Soup

Garden Fresh Tomato Soup | Photo by Stella Reynoso

Brown Roux

Brown roux is cooked about 35 minutes until it reaches a peanut butter-brown color. Its aroma is more pronounced and sharper than the nutty smell of blond roux. Cooked to this stage, flour begins to lose its thickening power, requiring more roux to thicken a given amount of liquid.

Dark Brown Roux

Even darker than the preceding brown roux, dark brown roux is cooked approximately 45 minutes until it is the color of melted milk chocolate. Its aroma is mellower than the strong, roasted flavor of brown roux, and will actually smell a little like chocolate. This stage has the least thickening power of all four; its main purpose is as a flavoring agent with thickening being secondary.

Charleston Shrimp 'n' Gravy

Charleston Shrimp 'n' Gravy | Photo by Caroline C

How to Store Roux

Having a stash of cooked roux in your fridge or freezer saves time when it comes to making sauces and soups. Here's how to store it so it's ready when you are:

  • Carefully pour the finished roux onto a baking sheet or into ice cube trays and place in the refrigerator to cool.
  • Refrigerate the roux for several hours or overnight until it has hardened completely. 
  • Roux will keep indefinitely when stored in the refrigerator or freezer in an airtight container. Roux made with vegetable oil can be stored at room temperature for several weeks, but roux made with butter or fat should always be refrigerated.
Macaroni and Cheese

The creamiest mac and cheese starts with roux. | Photo by Meredith

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