It is similar in taste to hot mustard or horseradish rather than chilli peppers, in that it stimulates the nose more than the tongue, but freshly grated wasabi has a subtly distinct flavour.

[14] Wasabi flowers appear in clusters from long stems that bloom from late winter to early spring.

Traditionally, coarse sharkskin is used to grate the root, but metal graters called oroshigane are used in modern times.

Fresh wasabi leaves can be eaten raw, having a spicy flavor,[20] but a common side effect is diarrhea.

[14] Wasabizuke is made of wasabi leaves pickled in sake lees, and is considered a specialty of Shizuoka Prefecture.

Wasabi favors growing conditions that restrict its wide cultivation – among other things, it is quite intolerant of direct sunlight, requires an air temperature between 8 and 20 °C (46 and 68 °F), and prefers high humidity in summer.

A common substitute is a mixture of horseradish, mustard, starch, and green food colouring or spinach powder.

[29] The chemical in wasabi that provides its initial pungency is the volatile compound allyl isothiocyanate, which is produced by hydrolysis of allyl glucosinolate, a natural thioglucoside (conjugates of the sugar glucose and sulfur-containing organic compounds); the hydrolysis reaction is catalyzed by myrosinase and occurs when the enzyme is released on cell rupture caused by maceration – e.g., grating – of the plant.

[34] The unique flavour of wasabi is a result of complex chemical mixtures from the broken cells of the plant, including those resulting from the hydrolysis of thioglucosides, including sinigrin[35] and other glucosinolates, into glucose and methylthioalkyl isothiocyanates:[18][30][31] Such isothiocyanates inhibit microbial growth, perhaps with implications for preserving food against spoilage and suppressing oral bacterial growth.

[36] Because the burning sensations of wasabi are not oil-based, they are short-lived compared to the effects of capsaicin in chilli peppers and are washed away with more food or liquid.

Inhaling or sniffing wasabi vapor has an effect like smelling salts, a property exploited by researchers attempting to create a smoke alarm for the deaf.

One deaf subject participating in a test of the prototype awoke within 10 seconds of wasabi vapour sprayed into his sleeping chamber.

[37] The 2011 Ig Nobel Prize in Chemistry was awarded to the researchers for determining the ideal density of airborne wasabi to wake people in the event of an emergency.