Wasabi

Not chilli heat

Wasabi heat is fundamentally different from chilli heat. Chilli’s pungency (capsaicin) stimulates heat receptors in the mouth and builds with repeated exposure. Wasabi’s pungency comes from allyl isothiocyanate — a volatile compound that vaporises rapidly and travels up through the nose and sinus passages, causing an intense, sharp, almost electric nasal sting. It disappears within 30–60 seconds. This is why wasabi is described as a “head rush” rather than a mouth burn.

Real wasabi is rare

Genuine wasabi (Eutrema japonicum) is extremely difficult and expensive to grow — it requires clean, cold, running water, specific temperature ranges, and 18–24 months to mature. It is grown in mountain stream valleys in Japan, where conditions are difficult to replicate. As a result, true wasabi commands prices of £100–£200/kg and is rarely found outside high-end Japanese restaurants. The green paste served everywhere else is horseradish dyed green.

Grating ritual

The correct method for preparing wasabi is grating the rhizome on a traditional oroshi grater (historically made from sharkskin, now ceramic or metal). The finest possible grating develops the volatile compounds most fully. Grated wasabi should be served immediately — it loses its sharpness within 15 minutes as the volatile isothiocyanates dissipate.

Health research

Wasabi contains several bioactive compounds under investigation for health benefits: the isothiocyanates have shown antimicrobial properties against pathogens including H. pylori; 6-methylsulfinylhexyl isothiocyanate (6-MSITC) has shown promise in cancer research and cognitive function studies.