Calories in Mustard

What makes mustard so powerful?

Mustard's pungency is a chemical defense mechanism that only activates when the seed's cells are crushed and exposed to water. Intact mustard seeds are virtually odorless and tasteless. They contain a compound called sinigrin and an enzyme called myrosinase, stored in separate cellular compartments. When water breaks down the cell walls, myrosinase converts sinigrin into allyl isothiocyanate—the volatile compound responsible for mustard's sharp, sinus-clearing heat. This reaction is highly temperature-dependent: cold water produces a highly pungent, volatile heat, while hot water or acidic environments denature the enzyme and produce a milder, more bitter flavor. This is why Chinese hot mustard, mixed with cool water, delivers a fierce punch, while classic American yellow mustard, blended with vinegar and turmeric, offers a gentle tang. The Romans were the first to experiment with this chemistry, grinding seeds and mixing them with unfermented grape juice, called must, to create mustum ardens—the burning must that eventually gave the condiment its modern English name.