What is a roux and how does its color affect a sauce?

• A. A roux is a dairy-based sauce thickener; color does not matter.
• B. A roux is equal parts fat and flour cooked to varying colors; white, blonde, or brown roux each thickens and flavors differently.
• C. A roux is a type of clarified butter used for searing.
• D. A roux is a sauce made from eggs and wine.

Answer: (B)

Roux is equal parts fat and flour cooked together to thicken sauces. The color you reach depends on how long you cook it, and that color signals both flavor and the sauce’s appearance. A white roux is cooked briefly for a pale, neutral thickener; a blond roux is cooked a bit longer to develop a light toasty note; a brown roux is cooked even longer for a deeper, nutty flavor and darker color. All provide thickening, but darker roux bring more pronounced flavor and color to the sauce while offering slightly less thickening power than a pale roux. That’s why the best answer describes roux as fat and flour cooked to varying colors, with each color thickening and flavoring the sauce differently.