First You Make a Roux

 

Roux (pronounced "roo") is a classic French thickening agent for soups and sauces, 
with roots dating back more than 300 years in French cuisine. It's the staple of 
every New Orleans kitchen.  It's so much a part of the culture of the city that the 
popular expression, "First you make a roux," jokingly refers to the fact that that's 
how almost every New Orleans recipe begins.


Made by cooking a flour and oil paste until the raw flavor of the flour cooks out and 
the roux has achieved the desired color, a properly cooked roux provides silky-smooth 
body and a nutty flavor while thickening soups and sauces.  Pre-cooking flour allows 
the starch granules to absorb moisture, and lets you thicken a sauce base without the 
flour clumping. Rouxs are also used to deepen the flavor of a sauce: browning the 
flour gives it a nutty, toasted flavor.


Roux can be made with a variety of oils and animal fats. It is commonly made with butter, 
vegetable oil or olive oil, but can also be prepared with bacon grease or other rendered 
fats. Its distinction from other thickeners is that the starch, in this case flour, is 
cooked before use.  Cooking removes the flour's raw taste, but maintains its excellent 
thickening properties. 


When cooked to a golden or brown stage, roux takes on a rich, toasted flavor, adding color 
to a soup, stew, sauce, or other dish. Roux can be white, blond, brown, or dark. The color 
depends on how long you cook the fat-flour mixture. While none are better or worse than 
the others, it does affect flavor and how much the roux can thicken. 


To make a basic roux, use equal weights of fat and flour. Four ounces of fat and four ounces 
of flour equal about 8 ounces of roux (moisture will evaporate). If you don't have a kitchen 
scale, one tablespoon of flour equals about ¼ ounce. One tablespoon butter = ½ ounce. 


Melt the butter (or whatever fat or oil you're using) over medium heat; slowly add the flour, 
whisking constantly. The mixture will thicken within 2-3 minutes. A white roux is done when 
the flour loses its raw smell and begins to develop a toasty aroma. Darker roux are cooked, 
stirring constantly, until the desired color. If you're not adding liquid, immediately remove 
the pan from the heat and transfer the roux to another container to cool. Be very careful of 
the hot fat-flour mixture. 


Refrigerated or frozen roux will keep well for up to two months and can be added directly to 
soups or sauces for quick thickening.