Black mustard is an ancient plant that has been in cultivation for
thousands of years and remains an important trade crop today. The seed
is used to make a variety of condiments, most notably the vinegar-based
mustard used as sandwich spread and dipping sauce.
Although mustard seeds look and smell mild, they heat up in flavor when
crushed or ground and introduced to cold water. This is because a
sulphur compound is produced by the interaction between two chemical
components in the seeds — myrosin and sinigrin, an enzyme and
glycoside, respectively. It's interesting to note that this reaction
doesn't occur to this degree if hot water or vinegar is used instead, or
if
salt is added to the mixture.
