Roux

I was recently asked a question about roux, so I thought I would answer it here.

Roux-thickened Chowder

Roux is a mixture of cooked flour and butter or oil that is classically used as a thickening agent in soups and sauces. Many contemporary recipes forgo the use of roux and instead use the Singer Method (pronounced "sawn-jay"), which is basically cooking aromatics in fat, then sprinkling with flour before adding liquid to make a soup or sauce. This method is quick and can work well if you are following a well-tested recipe with very exact measurements, but we're not always that lucky! Understanding as well as knowing how to make and use roux is an important skill for any avid cook.

Classically, roux is composed of 60% flour and 40% oil or butter BY WEIGHT. I have in a pinch, however, used equal parts flour and butter with decent results. Clarified butter (butter that has been melted very slowly so that the proteins and water separate from the fat and are then skimmed off) is preferred because of its flavor and lack of water, but oil or whole butter can also be used. Just melt your butter first then whisk your flour into it. I like to use a small sauté pan for this step.




Colors of Roux

Once your flour is whisked in, heat your sauté pan briefly over medium-low heat and stir. Your roux should be the consistency of wet sand. At this point, you have what's known as White Roux. If you continue cooking your roux, stirring often, until it achieves a light brown color and has a hint of a nutty aroma, you now have what's known as Pale or Blonde Roux. If you continue to cook your roux until it's much darker and has a strong nutty aroma (yum!) that is known as Brown/Dark Roux. You can also achieve this process in a 350°F oven. Doing it this way takes longer, but you will have more even results.

The uses of white, pale/blonde, and brown/dark roux vary. Basically, if you are making a white soup/stew or sauce, you'll use white or pale roux. If you are making a dark soup/stew or sauce, use a blonde or dark roux. The more color your roux has, the more flavor it has.

The flip side to the flavor bonus is that brown/dark roux has less thickening power than white and pale/blonde roux. (In other words, it takes more brown roux to thicken the same amount of liquid as a lighter roux.)
Here is a basic guideline of how much pale/blonde roux to use for every GALLON of liquid you are trying to thicken. If you are using white roux, you use a little less and if you're using dark/brown roux, you should use a little more:

Consistency of Soup/Sauce Desired	Total Weight of Roux	Weight of Flour (60%)	Weight of Butter (40%)	Per Amount of Liquid
Light	12 oz	7.2 oz	4.8 oz	1 Gallon
Medium	16 oz	9.6 oz	6.4 oz	1 Gallon
Heavy	18 oz	10.8	7.2 oz	1 Gallon

 
When incorporating roux into liquid, it’s best that your roux and your liquid are opposite temperatures (i.e., sauce is hot but roux is cold), because they are easier to mix that way. If they are not opposite temperatures it's vital to "temper" the roux into the liquid, meaning you put a little bit of the liquid in with the roux and whisk it. Continue adding liquid to the roux until there are no more clumps, THEN you add that mixture into your main pot with the rest of your liquid/stew/soup/sauce.  When in doubt, temper your roux into your liquid using this method to ensure you don’t get flour clumps.


Regardless, when using roux (or when using flour to thicken a liquid at any time), you MUST bring your liquid to a simmer to achieve the thickening power (at least 180°F).  Generally you will need to simmer for at least 15 minutes to remove the flour flavor.

You can use your roux right away or store it in the fridge! Let me know how it goes!