Cooking Tips · Ingredients · Techniques

Making a roux – a necessary skill

Something that is often used in our kitchens is something called a “roux”. Whether or not you knew the name, I am sure you have made it. What a roux is, how to make it and how to use it is the subject of this Cooking Tip.

Roux is a French term that literally translates to Red. In simple terms, it is a mixture of starch and fat that, after being cooked over heat, is used to thicken liquids but it also adds flavor. The starch that is most commonly used is flour and the classic fat is butter. The Professional Chef by The Culinary Institute of America defines a basic roux as 6 parts flour to 4 parts fat, by weight. However, most sources recommend a 1:1 ratio of flour to fat.

One can use either the stovetop or oven method although the stovetop is the most common. The procedure is to melt the fat in a saucepan without browning it. The flour is whisked into the melted fat to form a paste. This is then cooked to eliminate the raw flour taste and aroma. How long you cook it will depend on what type of roux you want. The length of cooking does affect the thickening ability of the roux. The longer you cook it, some of the starch in the flour breaks down resulting in less thickening power. To compensate for this, add about 25% more flour for a longer cooking roux.

Liquid is then added in a thin, steady stream (or a couple of tablespoons at a time), whisking all the time to achieve a homogenous consistency. Adding it slowly or in small increments will produce a much smoother sauce. If you do get clumps, whisk vigorously or use an immersion blender to smooth it out. As the sauce is then brought to a simmer, it will start to thicken. The heat should be reduced as you continue to stir until the sauce coats the back of a spoon (nappé stage). At this point, season with salt and pepper and any other desired seasoning.

The advantage of the stovetop method is that it cooks relatively quickly. The downside is you must keep your eye on it so it doesn’t darken too much or burn.

A roux may also be cooked in an oven but for a blond roux, it can take up to 1½ hours at 350 degrees. It must cook even longer for a darker roux. It can cook without a lot of your attention but what you save in that aspect, you lose in time.

Substitutions for butter

  • Lard – better for more rustic dishes such as gumbo than for delicate white sauces.
  • Oil – it is fine to use an oil but realize that stronger flavored oils will give that same flavor to your roux and eventual sauce. Therefore, you will probably want to use a neutral oil. Also, if you are going to do a darker roux, you will want an oil with a high smoke point. Oil will not, though, give you the richness that butter imparts.

Substitutions for flour

  • Rice flour – this is a nice gluten-free alternative and can be substituted 1:1 for the flour.
  • Cornstarch– this has a higher starch content than flour and therefore, will need more liquid. It is usually made into a “slurry” by mixing it with liquid and added near the end of the cooking process to achieve the thickness you want. Start be mixing 1 tablespoon of cornstarch with 1 tablespoon of cold liquid.
  • Arrowroot – similar to cornstarch but use only 2½ teaspoons to 1 cup of liquid. Arrowroot does not require cooking. In fact, heat and abundant stirring can inhibit the thickening power.
  • There are some other differences between these starches.
    • A grain-based starch (flour, cornstarch, rice) gives you great thickening but does look slightly opaque when it is cool. It can actually set up into a gel that can be sliced or molded. It can be re-heated without thinning out but should not be frozen as it can get watery when thawed.
    • A root or tuber starch (arrowroot, potato starch, tapioca starch) is great when you want the product to be clear and glossy when set. Although it thickens well, it does thin some when it cools. It will thin if reheated but does freeze and thaw well.

Types of roux

  • White roux – it is barely colored, chalky or very light beige. It normally takes less than 5 minutes to make. It is used to make a white sauce such as a bechamel, which can be served on its own or used to make a macaroni and cheese. It is also used to thicken soups.
  • Blond roux – this is golden in color with a slight nutty aroma. It may take up to 15 minutes to get to a blond color. This is commonly used to make gravy but can be used in other sauces and to thicken soups.
  • Brown roux – this roux is deep brown with a pronounced nutty aroma and may take up to 30 minutes or so. It is typically used to make a brown sauce such as espagnole.
  • Dark roux – taking up to 45 minutes, it is commonly used for Cajun and Creole dishes. Because of the prolonged cooking time, it will add flavor but will have lost much of its thickening ability. Most cooks will opt for oil over butter due to the long cooking time as it would be very easy to burn butter.

One ounce of roux will thicken one cup of liquid to the nappé stage. You may adjust the amount of roux based on how thick you want the finished product.


Let cool to room temperature; transfer to air-tight container or bag. Refrigerate and it should last up to a month. For longer storage, freeze either in small bags or ice cube trays. It can last up to a year.

As I said earlier, I am sure you have made a roux but for most of us, it would probably have been a white roux or maybe a blond one. I hope this Tip will not only help you understand a roux but will help you see how you can manipulate it for different results.