Wasabi

Wasabi refers to the pungent green condiment derived from the rhizome of the plant Eutrema japonicum, a member of the Brassicaceae family. Also called Japanese horseradish, real wasabi is produced by cracking the fresh rhizome to release volatile compounds that give the characteristic aroma and heat. In commercial markets, “wasabi” often denotes a paste or powder made from horseradish, mustard, starch, and green coloring rather than true wasabi.

Flavor and chemistry: The heat of wasabi comes mainly from allyl isothiocyanate, formed when the plant’s cells are crushed. The sensation is sharp and nasal, typically lasting only a short time and often described as clean or citrusy rather than the lingering burn associated with chili peppers.

Preparation and uses: Fresh wasabi rhizomes are grated, traditionally on a sharkskin or ceramic grater, to produce a bright green paste. It is commonly served with sushi and sashimi, or mixed lightly into soy sauce for dipping. Fresh wasabi has a short shelf life and is best used soon after grinding; refrigeration can slow deterioration but flavors diminish with time. Powdered wasabi can be rehydrated into a paste.

Cultivation and production: True wasabi requires cool temperatures, high humidity, and running water, making it difficult to cultivate at scale. Consequently, real wasabi production is limited and costly, concentrated in Japan with some cultivation in New Zealand, China, Korea, Canada, and parts of North America. Market prevalence of imitation wasabi, made from horseradish, is common in many regions.

Varieties and substitutes: Outside Japan, most products labeled wasabi are blends or substitutes rather than fresh wasabi, though some producers offer true wasabi roots or rhizomes.