Robuchon's treatment of the five French mother sauces — béchamel, velouté, espagnole, hollandaise, and sauce tomat — represents both the classical technique and the modern refinements. Each mother sauce is a technical platform from which derivative sauces are made: the French sauce tradition is a branching tree rather than a collection of individual recipes.
**Espagnole → demi-glace → sauce bordelaise, sauce périgueux, sauce financière:** - Espagnole: brown veal stock + brown roux + tomato. - Demi-glace: espagnole reduced by half, then mixed with brown veal stock and reduced again — concentrating the flavour while clarifying the texture. **Hollandaise:** - Clarified butter emulsified into egg yolks with lemon juice — the unstable warm emulsion requires constant temperature monitoring. - If the sauce breaks (fat separates from the yolk emulsion): the pan was too hot. Salvage: add ice cold water and whisk vigorously. **Beurre blanc (not a mother sauce but Robuchon's critical derivation):** - Shallot reduction in white wine and white wine vinegar, then cold butter whisked in over low heat. - The lecithin in the butter stabilises the emulsion; the acid from the reduction is the flavour.
The Complete Robuchon