Can You Use Whole-Wheat Flour in a Roux?

Roux is typically made with all-purpose flour, but can you use whole-wheat flour instead? It depends on the recipe and the style of roux you're making. All-purpose flour has a significantly higher starch content than whole-wheat flour. Since starch is what gives the roux its thickening power, a roux made with whole-wheat flour won't thicken a sauce as much as one made with all-purpose flour. The presence of the bran in whole-wheat flour will also lend the roux a reddish-brown color, a nutty wheat flavor, and a slightly coarse or grainy texture.

We don't recommend whole-wheat flour for light-colored roux. To demonstrate why, we made two batches of the Mornay sauce in our recipe for croque monsieur sandwiches with the two different types of flour. The Mornay made with whole-wheat flour was browner, grainier, and soupier than the one made with all-purpose flour (which was pale, smooth, and perfectly spreadable).

That said, whole-wheat flour was fine for the chocolate-colored roux in our recipe for Cajun Meatball Fricassee. Darker roux are employed more for their flavor than for thickening. In this case, the bolder flavor of the whole-wheat roux worked just fine in the robust stew, and any graininess was imperceptible.

THE BOTTOM LINE:  Don't use whole-wheat flour for a light roux in any recipe where the finished sauce requires a precise texture and delicately balanced flavor. You can, however, use whole-wheat flour for a dark roux in boldly flavored recipes such as gumbo or Cajun fricassee.