How is Hollandaise sauce traditionally prepared to ensure a stable emulsion?

• A. Egg yolks are gently heated with clarified butter and whisked continuously (often over a double boiler) to form a stable emulsion.
• B. Butter is melted and poured in without emulsification.
• C. Egg whites are whipped until stiff and folded in.
• D. A roux is used to thicken it.

Answer: (A)

Emulsification is what makes Hollandaise hold fat and water together. Egg yolks contain lecithin and other proteins that act as emulsifiers, so when you gently heat the yolks and whisk, they create a warm, stable base. Melted clarified butter is then added very slowly in a thin stream while you keep whisking hard. The heat and constant mixing coax the tiny butter droplets to stay dispersed in the yolk mixture, forming a smooth, cohesive emulsion.

Keeping the heat gentle—usually around 60°C (about 140°F)—is crucial. Too much heat or adding butter too quickly can cause the yolks to curdle or the emulsion to break, leaving a separated sauce. The double boiler helps control temperature and prevents direct heat from scorching the yolks.

Other methods don’t achieve the same stable emulsion: pouring melted butter in without emulsification won’t suspend fat in water, whipping egg whites adds air but lacks the yolk’s emulsifying properties, and a roux thickens with starch rather than creating a fat-in-water emulsion.