Q. What is the difference between hollandaise sauce and béarnaise sauce?
Some people believe they are first cousins, when in fact, they are mother and daughter. Both are warm emulsion sauces, in which a lot of warm butter is emulsified with egg yolks into a small amount of acidified liquid. Madeleine Kamman, author of The New Making of a Cook (Canada, UK), says they are essentially warm flavored mayonnaises.
Hollandaise came first and is considered the mother of the warm emulsified sauces. Béarnaise is the best known and certainly best loved variation. The ingredients for hollandaise sauce are water, lemon juice, salt, white pepper, egg yolks, and butter. It is traditionally served with poached fish, boiled or steamed vegetables, and somewhat more recently, with Eggs Benedict. Béarnaise sauce substitutes vinegar for the water, and adds shallots, tarragon, chervil, and (sometimes) parsley, thyme, bay leaf, and cayenne pepper. It is most often served with grilled meat or fish.
Among the variations of hollandaise are Mousseline Sauce (with cream added), Maltaise Sauce (with orange juice and zest), Mikado Sauce (with tangerine juice and zest), mustard sauce (with white mustard). There are also versions with horseradish, anchovies, or capers. Among the descendants of béarnaise sauce are Choron Sauce (with tomato), Valois Sauce (with veal stock), and Paloise Sauce (with mint instead of tarragon).
For your own edification, we suggest you whip up both sauces and see for yourself what the differences are. And just for you, we've provided recipes for each: Hollandaise Sauce and Béarnaise Sauce.