Beurre Marchand de Vin — wine merchant's butter — is the compound butter that bridges the gap between a cold butter preparation and a warm sauce, incorporating a concentrated red wine and shallot reduction that gives it extraordinary depth and a distinctive mauve-tinged colour. Where beurre maître d'hôtel is immediate and fresh, marchand de vin is brooding and complex, the ideal partner for robust grilled meats, particularly entrecôte, onglet, and thick-cut bavette. The preparation begins with a reduction: combine 200ml of full-bodied red wine (Cahors, Madiran, or a good Côtes du Rhône) with 2 finely minced shallots, a sprig of thyme, half a bay leaf, and 6 crushed peppercorns. Reduce over medium heat until only 2-3 tablespoons of syrupy liquid remain — this concentration is critical, as it must flavour 250g of butter without adding excess moisture. Strain through a fine sieve, pressing the shallots to extract every drop of flavour, and cool completely. This cooling step is non-negotiable: adding warm reduction to butter will melt it, destroying the emulsion and producing a greasy, split mess. Beat the cooled reduction into softened butter (15-16°C) along with a tablespoon of finely chopped parsley, a squeeze of lemon juice, and seasoning. The butter should be smooth, evenly coloured, and aromatic. Roll in cling film, chill, and slice as for maître d'hôtel. Some chefs add a teaspoon of demi-glace or meat glaze to the reduction for even greater depth. The result is a coin of butter that, when placed on a grilled steak, melts into something approaching a bordelaise sauce in concentrated form — wine, shallot, and butter creating a trinity that has defined French steak cookery for centuries.
Red wine reduction must be fully concentrated (200ml down to 2-3 tablespoons) before incorporation. Cool the reduction completely — warm liquid destroys butter emulsion. Full-bodied red wine (Cahors, Madiran, Côtes du Rhône), not light or acidic wines. Strain and press shallots to extract maximum flavour. Standard compound butter technique: roll, chill, slice.
A half-teaspoon of meat glaze (glace de viande) in the reduction creates extraordinary meaty depth. Make the reduction a day ahead — it concentrates further in the fridge. This butter freezes beautifully for 3 months. For a restaurant shortcut, reduce wine with a tablespoon of demi-glace instead of long reduction. The same technique with white wine and fish stock creates beurre de poisson for sole and turbot.
Not reducing the wine enough — excess liquid makes the butter loose and difficult to roll. Adding warm reduction to butter, causing it to melt and split. Using cheap, thin wine that lacks body for proper reduction. Forgetting to strain, leaving shallot pieces that create uneven texture. Under-seasoning — the wine's tannins need salt to balance.
Le Guide Culinaire — Auguste Escoffier