The Food Lab: Better Home Cooking Through Science

a touch of lemon juice. It should flow slowly off a spoon so
that it naps a poached egg in a thick robe. Never runny, and
certainly never curdled, hollandaise has a delicate texture
that’s really tough to get right. At least, it used to be. I’ve
figured out a way to make it perfectly every single time—
even with no experience.
Hollandaise sauce, just like mayonnaise, is an egg-
stabilized emulsion of fat in a water-based liquid (see
“Obsessive-Emulsive,” here). It’s traditionally made by
cooking egg yolks with a little water, whisking them
constantly, until they’ve just begun to set, then slowly
drizzling in melted clarified butter (see “Clarified Butter,”
here) and seasoning the sauce with lemon juice. With
vigorous whisking, the butterfat gets broken up into
microscopic droplets that are surrounded by the water from
the lemon juice and the egg yolks. Both the acid in the
lemon juice and the protein lecithin in the egg yolks prevent
these fat droplets from coalescing and breaking down into a
greasy pool. The result is a thick, creamy, delicious sauce.
Mayonnaise is relatively simple: it’s made from a liquid
fat (oil), and it’s made and kept at room or fridge
temperatures (for a foolproof recipe, see here). Hollandaise
is more complicated. Butterfat begins to solidify below
95°F, so if you let your hollandaise get too cool, the solid
chunks of fat will break the emulsion, turning it grainy.
Reheat it, and it will separate into a greasy liquid (that’s why
leftover hollandaise can’t be stored). On the other hand, if
you let it get too hot, the egg proteins will begin to
coagulate. You’ll end up with a lumpy, curdled sauce with
the texture of soft scrambled eggs. So the keys to a perfect