Mustard contains an enzyme that must be activated by water (or beer) to develop its sinus-clearing heat. Once activated, wine, vinegar, etc. can be added to moderate and stabilize heat and flavour. For hot mustard for the table, add a little cold water and let it sit for a few minutes. Japanese mustard powder, Karashi, is finely ground, de-husked mustard seed. It is fiery hot; an excellent substitute foe “English” mustard. The Japanese dab a tiny amount on the inside rim of the bowl in which Oden (fish cakes, konyaku, vegetables etc. simmered in broth) is served. Minute amounts are transferred to the food with the tip of a chopstick.