Swedish-style mustard and dill sauce

A mustard sauce for cured salmon

Hovmästarsås is a Swedish mustard and dill sauce, sweet and sharp at once and thick enough to sit on a slice of fish. ICA, the Swedish grocery chain, publishes its own recipe and calls it a classic, perfect served the traditional way with gravad lax, the cured salmon, while adding that it suits other dishes too. Its ingredient list explains the sauce: two tablespoons of Swedish mustard and one of Dijon, a tablespoon of sugar, half a teaspoon of salt, a pinch of black pepper, a tablespoon of white wine vinegar, two decilitres of oil and a pot of dill, chopped.

ICA's method is the method of an emulsion. The mustards, sugar, salt, pepper and vinegar are mixed first; the oil then goes in drop by drop or in a thin stream, with vigorous stirring, until the sauce turns thick; the chopped dill is stirred in last. Whisking oil gradually into a smaller volume of water-based liquid breaks it into fine droplets, and the thick mustard base helps hold them apart, which is where the body of the sauce comes from. If the oil goes in too quickly the sauce stays thin or separates; added slowly, it thickens as it goes.

That makes hovmästarsås a prepared sauce made with mustard, sweet, tangy and emulsified with oil, rather than a mustard you could swap for the contents of a jar.

How this formula differs

This version weighs everything and keeps ICA's architecture: two mustards, 70 g of a mild sweet prepared mustard and 20 g of Dijon; white-wine vinegar; sugar; salt; oil whisked in gradually; 15 g of chopped fresh dill folded through at the end. It leaves out the black pepper and adds 4 g of water to help the 25 g of sugar dissolve. The largest difference is the oil. ICA uses two decilitres of oil against three tablespoons of mustard; this formula uses 90 g of oil against 90 g of mustard, so its sauce leans more on the mustard and less on the oil for body. Treat it as an interpretation, with ICA's recipe as the published Swedish point of comparison. It also uses less oil than some traditional recipes do.

Choose the sweet mustard with care, because it carries much of the sweetness: if yours is already very sweet, use less added sugar in the next batch. Serve the sauce cold with cured or cooked salmon, with potatoes or with another cold dish. Dill and the other fresh ingredients turn a jar of mustard into a new perishable sauce, so the unopened mustard's shelf life does not carry over. The formula has not been kitchen-tested or checked for keeping; refrigerate it promptly and use it within 48 hours or freeze it, a house convention rather than a measured shelf life.

The Dijon in the bowl

The 20 g of Dijon brings its own question, because a supermarket Dijon is not necessarily what its name suggests. Maille's US Dijon Originale lists water, mustard seed, vinegar, salt, citric acid and sodium metabisulphite, and no wine: fine texture, concentrated mustard character, sharp acidity and little deliberate sweetness. Maille's UK freshly pumped Dijon Originale is a distinct product containing 20% white wine. Wholegrain or à l'ancienne mustard is a third thing, distinguished by coarse grinding and visible seed fragments, and French rules define it separately from smooth mustard. Any of them will make the sauce, but each will make a slightly different one.

Nor does Dijon promise that the seeds grew near Dijon or that the jar was made there. Edmond Fallot, a Burgundy mustard house, describes Dijon mustard as a generic denomination, made in France and in many other countries. Moutarde de Bourgogne is different: a protected geographical indication registered by the EU in 2009, whose specification requires the seed to be grown, and every operation from storage to manufacture to take place, within a defined area of the Côte-d'Or, Nièvre, Saône-et-Loire and Yonne. It must be made with Burgundy appellation white wine, at least 25% of the dilution liquid for the smooth, sieved version and 15% for the à l'ancienne version. A home sauce made elsewhere can use a Dijon-style mustard; it cannot acquire Burgundy's protected origin by adding a bottle of Burgundy wine.