Which of the following is NOT a thickener?

• A. Roux
• B. Hollandaise
• C. Liaison
• D. Slurry

Answer: (B)

Thickening a sauce relies on a mechanism that increases viscosity. Roux thickens by cooking flour with fat, then adding liquid so the starch granules swell and gel, giving body. A slurry uses starch dispersed in cold water or another liquid and then heated to activate the starch and thicken. Liaison thickens by warming egg yolks (often with cream) to coagulate the proteins and create a smooth, richer texture, helping sauces become creamier and thicker without starch.

Hollandaise, on the other hand, thickens through the creation of a stable emulsion of egg yolks and clarified butter. It’s a finished emulsion-based sauce that supplies body via emulsification rather than thickening a separate sauce with starch or proteins. Because it isn’t a thickening method applied to other foods, it’s the one that isn’t a thickener.