To make a roux

A few Sundays ago we decided to make one of our favorite dishes: gumbo. For this, we use the recipe from Cook’s Illustrated book. The results are always amazing and there’s always enough left overs for a few days. Cooking gumbo, it turns out, takes a while but is not difficult. The biggest unknown is the roux.

Here’s the step on roux from the recipe:

Heat the oil in a Dutch oven or large, heavy bottomed saucepan over medium-high heat until it registers 200 degrees on an instant-read thermometer, 1 1/2 to 2 minutes. Reduce the heat to medium and gradually stir in the flour with a wooden spatula or spoon, working out any lumps that form. Continue stirring constantly, reaching into the corners of the pan, until the mixture has a toasty aroma is deep reddish brown, about the color of an old copper penny or between the colors of milk chocolate and dark chocolate, about 20 minutes. (The roux will thin as it cooks; it is begins to smoke, remove the pan from the heat and stir the roux constantly to cool slightly.)

The first time we did the recipe, it took us more than 80 minutes to get the roux to a copper color. We got a nice copper roux without ever burning the oil. You need dedication to your stomach though to move a wooden spatula in oil and flour for that long. You can’t let the roux alone otherwise clumps of flour will form. The entire recipe took more than 4 hours to complete.

So what’s the trick to obtaining a dark roux in 20 minutes or less? Notice the words “reduce the heat to medium?” If you raised the temperature to 200 degrees then reduce the heat, will the temperature keep rising or will it drop below 200 degrees? The recipe doesn’t say. The sentence is misleading. This time, having other plans for my evening, I cheated; I raised the heat up to 350 degrees after adding the flour. By continuously stirring and monitoring the temperature, I kept the mixture right below the burning point. Low and behold the white roux became a dark roux in ~18 minutes.

There are two lessons here:

  1. Although America’s test kitchen’s recipes are wonderful, their recipes are often misleading and confusing. Read between the lines.
  2. Get yourself an instant read thermometer.

P.S.: Our other pet-peeve with Americas]’s Test Kitchen is that, in their big book, they didn’t total the preparation and cooking time for the recipes. You have to read the recipe very carefully ahead of time. Otherwise, what you think will take an hour turns into 3.

One Response to “To make a roux”

  1. Mark Says:

    I'’ve made roux myself without a thermometer, though. (I think requiring one is overkill). My recipe uses unsalted butter instead of oil.
    The Joy of Cooking has some good info on making roux (not that that this is also a generic term for fat and flour cooked together to thicken and flavour sauces). The dark brown roux is called brown or brick roux.
    The Joy of Cooking says “If a roux cooks to quickly, the resulting mixture will be grainy.” They also give 8-15 mins to make brown roux.

    PS: Have you seen the Good Eats episode on gravy and roux?