What are the mother sauces and why do they matter?

Escoffier's list of mother sauces is usually taught as a piece of culinary history, which makes it sound like something to memorise rather than something to use. It is more useful than that. What the list actually encodes is that a sauce is a liquid plus a way of giving it body, and there are only three ways of giving it body. Once you can name the mechanism your sauce is using, you already know its failure modes and its rescues.

Step by step

1. Béchamel — milk thickened with a white roux.Equal weights of butter and flour cooked without colouring, then milk. It gives parsley sauce, cheese or Mornay sauce, and the white layer of a lasagne. Faults are starch faults: lumps, a raw floury taste, and thinning on reheating.
2. Velouté — light stock thickened with a blond roux.The same roux taken a shade further and made with chicken, fish or veal stock rather than milk. Add cream and it becomes a suprême. It is the base of a chicken pie filling and of most white fish sauces.
3. Espagnole — brown stock thickened with a brown roux.Roux cooked to nut brown, brown stock, tomato and mirepoix, reduced. Reduce it further with more stock and it becomes demi-glace. This family is the ancestor of a proper restaurant gravy, and the reason a good gravy tastes different from a cornflour-thickened one.
4. Tomato — thickened by its own reduction, not by roux.The odd one out. There is no thickener at all; the sauce concentrates as water leaves. Its faults are therefore reduction faults: watery sauce, a scorched base, and salt or bitterness concentrating as it cooks down.
5. Hollandaise — butter emulsified into egg yolk with acid.The emulsion family. Béarnaise is the same sauce with a tarragon and vinegar reduction as the acid; mousseline is hollandaise with whipped cream folded in. Its faults are emulsion faults: splitting and curdling.
6. Use the mechanism, not the name, to diagnose a problem.A gluey cheese sauce and a gluey chicken velouté have the same cause, because both are roux sauces. A split hollandaise and a split beurre blanc have the same cause and the same rescue. Naming the mechanism first is quicker than searching for the sauce.

Tips

• Modern kitchens use far less roux than the classical system did. A pan sauce reduced and mounted with butter has largely replaced espagnole in restaurant cooking.
• The reason so many British household sauces are béchamel derivatives is that milk and flour were always in the house. There is nothing sacred about the ratio — it is a household ratio.
• Two more families are sometimes added: mayonnaise as the cold emulsion, and beurre blanc as the butter emulsion. Both fit the emulsion mechanism exactly.
• If a sauce uses two mechanisms — a roux-thickened sauce finished with butter, say — it inherits both sets of faults.

Questions people ask