Knowing how to make a roux should be at the top of this list. From a smooth, creamy béchamel to the base of a gumbo – a roux is a technique to master, to love. It can be intimidating due to the ease with which it can be burned – and ruined – but it is nothing that a little practice can’t resolve.
A roux is paste that is used as a thickener. It is simply flour cooked in fat. 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 and creates a more even and smooth texture.
How to Make a Roux
First, a fat—butter, oil, rendered animal fat—is melted in a heavy-bottomed pan. When it is has been heated, an equal amount of flour is added. The mixture must be whisked constantly, as it will burn very easily, until it has been cooked to the desired color.
There are three major categories of roux that are dependent on the length of cooking. A white 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 continue to brown. The darkest roux the brown roux which, having cooked the longest, has the deepest smell, flavor, and color. One thing to note is that the longer a roux is cooked—and the darker it becomes—the less ability it has to thicken. Therefore you will need more of a darker roux to thicken to the same degree than the same quantity of a lighter roux.
A watched pot never boils but an unwatched roux will always burn.
The thing that is 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.
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 butter.
Step 2: Heat your butter in a heavy pan over low heat. When the butter has melted and the foaming subsides, add your flour. The quantities should be the same. For example, if you use two tablespoons of butter, you will want to use two tablespoons of flour.
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.