How to make mustard

How the heat is made

A mustard seed contains an inert precursor compound and, kept separately within the seed, an enzyme. Crushing the seed and adding water brings the two together, and the enzyme converts the precursor into the pungent compounds that make mustard hot.

This takes about ten minutes and it needs cold water. Hot water denatures the enzyme before it can work, which is why mustard made with boiling water is mild and bitter rather than fierce.

Acid stops the reaction and fixes whatever heat has developed. So vinegar added immediately gives a mild mustard; vinegar added after ten or fifteen minutes gives a much hotter one. This is the single most useful lever in the whole process.

Wholegrain mustard

The easiest, and it needs only patience.

1. Soak a mixture of yellow and brown mustard seeds in cold vinegar and cold water — around half and half — overnight or for a day.
2. The seeds swell and soften and absorb most of the liquid.
3. Blitz or pound roughly, leaving plenty of whole seeds. Add more liquid if it is too stiff.
4. Add salt, and any flavourings — honey, a little sugar, tarragon, horseradish, beer or cider.
5. Taste it. Freshly made mustard is harsh and unpleasantly bitter, and this is normal.
6. Jar it and leave it for at least a week, and preferably two or three. The bitterness fades and the flavour rounds out.
7. Store it in the fridge. Mustard loses its pungency over months as the volatile compounds escape.

The seeds and the styles

Yellow / white seed

Mild, with a lingering warmth rather than a sharp hit. The base of American and most wholegrain mustards.

Brown seed

Much hotter and more pungent, with heat that hits the nose. Used in English, Dijon and Indian cooking.

Black seed

Hottest of all, used mainly in Indian cooking, often fried whole in oil rather than made into mustard.

English mustard

Brown and yellow seed ground to a fine powder, mixed with cold water at the table. Ferocious and short-lived.

Dijon

Brown seed with verjuice or white wine. Smooth, sharp and less fierce than English.

Variations

• Honey mustard, with honey stirred in after the heat has developed.
• Beer mustard, using ale in place of some of the water. Traditional in Germany and Belgium.
• Tarragon mustard, which is the classic French flavouring.
• Horseradish mustard, which stacks two different kinds of heat.
• Mustard with cider and apple, a British direction.
• Green peppercorn or Sichuan pepper mustard, for something more unusual.
• English mustard powder mixed at the table, which is at its hottest ten minutes after mixing and fades within an hour.

Common questions