Most people think they know what wasabi tastes like, but they're wrong. The green, pasty stuff you get at the average sushi place isn't grated wasabi root; it's almost always stronger-tasting horseradish mixed with mustard and food colouring to tint it the familiar green. Occasionally, the tubes, which are similar to toothpaste tubes, contain real wasabi root, but the stabilisers used to prolong the shelf life alter the taste. Even chefs at upmarket Japanese restaurants sometimes use wasabi paste from a tube and will only serve the fresh root when requested. Diners have become so accustomed to the sinus-clearing cheaper alternative that, when served the real thing, they often complain that it's tasteless. Yes, fresh wasabi is strong, but it's much milder compared with commercial paste.
The gnarled root is grated into fine shreds using a special shark- skin grater.
The reason most restaurants don't serve fresh wasabi is that the root is expensive. Wasabi requires precise conditions to grow.
That's not to say faux wasabi can't be delicious, though. Wasabi-flavoured snacks include crunchy fried peas, tempura batter-coated seaweed, potato chips and rice crackers.
Japanese shops such as Fresh Mart (Sogo, Causeway Bay) and Apita (Taikoo Shing) occasionally sell fresh wasabi root. Look for firm roots with fresh-looking tops.
Wasabi paste in a tube is best enjoyed in small quantities. For a delicious salad dressing, mix a small blob of wasabi paste with neutral-tasting oil, a little sesame oil, rice vinegar and a splash of soy sauce. Mix this with salad greens, add a sprinkle of toasted sesame seeds and serve immediately.