Which thickening agent is commonly used to thicken gravies?

• A. Roux
• B. Cornstarch slurry
• C. Gelatin
• D. Beurre Manie

Answer: (B)

Thickening gravies relies on starch granules swelling when heated to trap liquid and create a cohesive, pourable sauce. Cornstarch slurry is commonly used because it thickens quickly and smoothly without adding noticeable flavor. You mix a small amount of cornstarch with cold water to make a slurry, then whisk it into the simmering gravy. As it heats, the starch granules gelatinize and the gravy thickens to a glossy, satiny finish. It’s easy to control—add more slurry in small amounts until you reach the desired thickness—and it works well with pan gravies that you want to finish quickly after cooking.

Other options have different trade-offs. A roux thickens gravies but requires cooking fat and flour together to develop flavor and takes longer to reach full thickness, often giving a deeper, toasted note. Gelatin would set the gravy into a gel rather than keep it as a smooth sauce. Beurre manié can finish a sauce but is harder to gauge and can lump if not whisked in properly.