What is an emulsion?
It is a mixture of two or more liquids that, under normal circumstances, are unmixable. Think water and oil. No matter how hard and how long you stir them together, they will always separate. To combine them, something else has to be added.
In the case of Hollandaise sauce, we want melted butter and lemon juice to combine without separating. The “something else” we need to add to make that possible is egg yolk. Raw egg yolks and lemon juice are initially whisked together over a pan of hot water until they are combined.
Does this first step cook the egg yolks? Well, if you’re thinking about safety from salmonella, egg yolks have to reach a temperature of 160F to go beyond the danger zone. At that temperature, the yolks will start to cook and coagulate. You can’t make Hollandaise sauce from coagulated egg yolks. So, no, the temperature of the egg yolks never reach 160F when making Hollandaise sauce.
So, once the egg yolks and lemon juice are combined, you have a base to which oil, in the form of melted butter, can be slowly added. This next stage can be done using nothing but a wire whisk. For convenience, you may use a blender, a hand mixer or a stand mixer. We prefer the stand mixer at home.
The egg yolk and lemon juice mixture is taken off the heat and slowly mixed together again to make sure that the mixture is smooth before the melted butter is added.
The melted butter is added very slowly. With the motor of the mixer running, a few drops of melted butter is drizzled in. Once incorporated, a few more drops go in, and so on, until the mixture is just starting to thicken. That’s the start of emulsification. At that stage, the melted butter can be poured slowly in a thin stream until all of it has been absorbed into the emulsion and the sauce has reached the ribbon stage.
- ¾ cup butter
- 2 large egg yolks
- 2 teaspoons lemon juice - mixed with one tablespoon water
- 2 pinches salt
- 1 pinch cayenne - optional
- Melt the butter and cool.
- Place a heat-proof bowl over a pan of barely simmering water (the bottom of the bowl must NOT touch the water).
- When the bowl is warm to the touch, pour in the egg yolks and lemon juice mixture, and start whisking them together immediately until lighter in color.
- Transfer the egg yolk mixture to the bowl of the stand mixer (or any mixing bowl if using a hand mixer).
- Start whisking the egg yolks over low speed.
- Turn up the speed to medium and start drizzing in the butter, a few drops at a time at the start.
- When the mixture starts to thicken, turn up the speed to high and pour the melted butter in a very thin stream.
- Continue whisking until the mixture is fully emulsified. To test, scoop with a spoon and allow to drip back into the bowl. If the liquid falls in ribbons, it is done.
- Taste the Hollandaise sauce and add as much salt as your taste buds require.