Horseradish and Wasabi

Although their flavors are similar, horseradish and wasabi do not come from the same plants. They both contain the highly volatile chemical allyl isothiocyanate, which instantaneously travels from the mouth to the nose, where it aggravates the sensory receptors and burns—that searing sensation you feel when you eat sushi daubed with wasabi, or prime rib dolloped with horseradish sauce. Both are best eaten raw and are usually prepared by finely grating the roots. The pungency begins to dissipate quickly with exposure to air, so use them soon after grating. Because hot temperatures destroy the enzymes that create the fiery heat of these ingredients, it is best to avoid heating horseradish or wasabi.