Mustard is the pungent seed of several plants in the cabbage family — chiefly yellow (Sinapis alba), brown (Brassica juncea) and black (Brassica nigra) — and the family of condiments made by crushing those seeds with water, vinegar or wine. The whole dry seed is almost odourless, but the moment it is ground and wetted it builds a sharp, eye-watering, sinus-clearing heat that ranges from the gentle tang of American yellow to the nose-prickling bite of English mustard and the wine-sharp warmth of Dijon. That heat is a physical, trigeminal burn rather than a fragrant bouquet, fleeting and volatile, which is why mustard is the classic foil for fatty meats, smoked fish and strong cheese, and the emulsifying backbone of vinaigrettes.