Béarnaise Sauce

Béarnaise is hollandaise with a different acid base. A reduction of dry white wine, white wine vinegar, minced shallots, and dried tarragon is cooked down until almost dry, strained, and used as the acid component in place of plain lemon juice. The technique from this point is identical to hollandaise: egg yolks and the reduction are whisked over indirect heat to ribbon stage, then clarified butter is incorporated drop by drop, then in a slow stream. The reduction gives the sauce a more complex, slightly herbaceous sharpness that pairs specifically with beef. Fresh tarragon, chopped, is stirred in at the very end after the sauce is off the heat. Adding it earlier cooks the tarragon and dulls its bright anise flavor. The egg yolks are doing the same work here as in hollandaise: providing the emulsification structure through lecithin and coagulating slightly to give the sauce body. The difference is entirely in the acid and the herb.