Which thickener is made of equal parts cooked flour and fat, heated to blend, color depends on heating time?

• A. Liaison
• B. Roux
• C. Temper
• D. Beurre Manie

Answer: (B)

Roux is a thickener formed by cooking equal parts flour and fat together until they blend into a smooth paste. The color indicates how long you cooked it—white roux is brief, blond roux is cooked a bit longer for a light tan, and brown roux is cooked even longer for a deeper, nutty flavor. The longer you cook, the less thickening power it has, so the color you choose also helps tailor both texture and flavor for the sauce.

Liaison thickens mainly with egg yolks and cream, not a flour-fat paste, so it doesn’t fit the description. Beurre mani is a paste of butter and flour used to finish sauces, but it’s not cooked to develop the distinct roux color and typically isn’t heated into the sauce in the same manner. Temper is a technique for gradually raising the temperature of eggs or dairy to avoid curdling, not a thickener.