Although we refer to this variety of ground mustard seed as “yellow mustard,” the plant that donates the seeds is actually known as white mustard.
Mixing yellow mustard seed powder with cold water will result in a particularly pungent mustard due to a reaction an enzyme called myrosin and a glycoside called sinigrin. Adding salt to the mixture, or mixing with hot water or vinegar, inhibits myrosin and results in a mustard with a milder, bitter flavor.
