How to Make Béarnaise Sauce

[Narrator] Making bearnaise sauce.

Bearnaise sauce is much like hollandaise.

It's an emulsified mixture of

egg yolks, butter, and a white wine reduction.

First, we need to reduce the herb mixture.

Start with a heavy saucepan and combine

the wine, vinegar, tarragon, shallots, and black peppercorn.

Bring all the ingredients to a boil

over a moderately high heat

and boil until reduced by about 75%.

This will take approximately eight minutes.

You want to remove it from the heat

and let it cool for five minutes.

Now, strain the liquid through a fine sieve.

Press on the solids to make sure you get out all the liquid

and then discard the solids.

This should produce about two tablespoons of liquid

for our recipe that makes one cup of sauce.

If you have less than two tablespoons,

add some water to bring it up to the full measurement.

Now, we're going to melt the butter.

Start with the heavy saucepan

and melt the butter over moderate heat.

Once the butter is completely melted,

remove the pan from the heat

and let it stand for three minutes.

Skim the foam from the top and set the butter aside.

Removing the foam helps the sauce to emulsify.

Next, let's gently cook the egg yolks.

Fill a saucepan 1/3 full of water

and bring it to a very gentle simmer.

Take the white wine-vinegar mixture that you just reduced

and whisk it together in a

heat-proof bowl with the egg yolks.

Clip a thermometer to the side

and set the bowl on top of the saucepan.

You could also do this in a double boiler.

Now, it's important to make sure that the bowl

doesn't touch the boiling water

or the eggs in the bottom will get overcooked and hard,

ruining the consistency of your sauce.

Whisk the mixture as it cooks.

It'll thicken and grow in volume.

It's important to keep whisking continuously

and to incorporate all of the egg yolks

by scraping down the sides and bottom of your pot.

Otherwise, some parts of the mixture

could overcook and form lumps.

Cook the mixture until the thermometer

reaches 140 degrees Fahrenheit

and stays there for three and a half minutes.

This is the amount of time it will take

to kill any salmonella in them.

You'll know the mixture is done

when thin, pale ribbons form when you lift the whisk.

This should take about eight minutes total.

Now, we're going to finish the sauce with the melted butter.

Gradually whisk the butter into the sauce

one teaspoon at a time.

As you whisk in the butter, the sauce will thicken.

It will also get smooth and shiny.

To serve, pour the sauce into a sauce boat

or directly over the dish.

Now, you can't chill bearnaise sauce.

It would ruin the texture.

But the sauce can be made up to

an hour ahead of time and kept warm.

Be sure not to keep the sauce warm for more than an hour,

because bacteria could grow.

We'll serve our sauce over a piece of sliced steak.