There are as many versions of gumbo as there are bars on Bourbon Street. But one thing that all traditional gumbo recipes have in common is a roux—a slow-cooked mixture of flour and fat that gives the gumbo its deep brown color, a bit of body, and a toasty flavor.
To guard against burning, the roux is stirred constantly over low heat, meaning it can take an hour or more of hands-on attention to make. But if you don’t have that kind of time or endurance, there’s another option: a dry roux, where the oven does the work for you.
In a dry roux, the flour is toasted without fat. It can be made on the stovetop or in the microwave, but after testing all three options for her Chicken and Sausage Gumbo recipe, Cook’s Illustrated test cook Annie Petito determined that the oven was the most reliable. She found that baking the flour in a skillet in a hot oven until it was the color of ground cinnamon gave her gumbo just the right amount of nutty toastiness along with an appealing rich flavor.
You can see this technique in action (as well as learn some great info on roux colors) in this clip with Bridget and Julia from America’s Test Kitchen:
So why does a dry roux work so well? As usual, it comes down to science. That toasty flavor happens when flour is heated to the point where its starch breaks down and undergoes the Maillard reaction, forming dark brown pigments and flavorful compounds. And because hot metal is a much better conductor of heat energy than oil is, a hot pan transfers heat more rapidly to dry flour than to oil-coated flour. So in addition to saving yourself from an hour or more of constant whisking, you get the same deep flavor considerably faster and without the added oil.
If you're looking to use a dry roux in your next batch of gumbo, here are some tips:
- Use a stainless-steel skillet or another light-colored skillet that can withstand high heat.
- Bake flour at 425 degrees on the middle rack. This allows the hot air to circulate evenly around the flour.
- Stir occasionally so the flour browns evenly. As it starts to color, it’s going to start going faster, so keep an eye on it towards the end of cooking.
- Once the flour reaches the desired color, remove it from the skillet. This prevents it from continuing to darken.
- You can toast the flour well in advance. The toasted flour can be stored in an airtight container in a cool, dry place for up to six months.
- To incorporate the flour into the gumbo, make a paste with some broth. To prevent clumping, gradually whisk in some room-temperature broth to the toasted flour before adding it to the pot.