Horseradish is the pungent white taproot of Armoracia rusticana, a hardy perennial of the cabbage and mustard family native to southeastern Europe and western Asia. The intact root is almost odourless, but the instant it is grated the cut cells release a volatile, eye-watering, sinus-clearing sharpness — the same airborne heat people know from mustard and wasabi. Grated and stabilised with vinegar it becomes the classic pungent condiment for roast beef, smoked fish and Eastern European tables, and outside Japan it is the root most often dyed green and sold as "wasabi." Its bite is fleeting and physical rather than fruity: a clean, mustard-hot rush that fills the nose and then fades.