All about real fresh wasabi
The global vogue for all things wasabi have seen products such as wasabi peas, wasabi popcorn, wasabi seaweed snacks, wasabi hummus and dips hit the shelves and becoming popular. However, maybe not many of us, know that all these years, the wasabi used in these products, the pasty green stuff that gets mixed in with the soy sauce which causes teary eyes, is actually not wasabi but horseradish. What we are being served on our platter of sushi is in fact a mix of horseradish, mustard, a little food colouring that have been reconstituted with water from a powder form. The likelihood of having ever tried the real thing outside of Japan is slim to none. If you look at the tube of paste or tin of powder that is claimed to be “wasabi” at the supermarket, you’ll find it will likely state on the packaging that it comes from Japan.
So what is the real deal?
Real wasabi (Wasabia japonica, or Japanese horseradish) is native to Japan, where it has been cultivated for at least a thousand years. It is extremely difficult to cultivate and the plant will not grow outside of Japan as it grows only in clear running water in high altitudes above 1000m. Another issue is that it takes 2 years for a single plant to reach maturity. These factors combine to make the cost of real Wasabi at up to $200 per Kg, far too expensive for the average restaurant or sushi lover. For these reasons, genuine wasabi is expensive and is rarely seen outside of Japan. The wasabi has a lot of spicy relatives. It’s a member of the Brassicaceae family, along with broccoli, kale, cauliflower, Brussels sprouts, mustard, and (European) horseradish. And it’s the European horseradish that we normally get with our sushi platters, ground into a nose-tingling paste, with an added dash of mustard and a splash of green food coloring. Wasabi and European horseradish are similar in the taste and pungency but wasabi is hotter and greener. A prime constituent of both is the sinus-zapping allyl isothiocyanate, where the heat is felt in the trigeminal nerve near the nose rather than in the back of the throat.
What is the difference then between wasabi and horseradish?
For one thing, the ingredients of real wasabi are volatile. The real wasabi stems lose potency 15 minutes after grating. Horseradish, on the other hand, stays hot for hours. Real wasabi has a more refined hotness, a sweet after-taste and is not nearly so bright a green as horseradish. Real wasabi starts to lose its flavor just minutes after grinding. It can’t be stored long enough to get it to supermarkets or home kitchens in paste form, and most people don’t know how to grind wasabi roots, which can makes it hard to get the right amount of wasabi into their dishes.
Why use horseradish?
Horseradish solves all of these problems. Horseradish becomes a good substitute with the right flavour profile and the most convenient way to capture that heat is to buy “wasabi” paste in a metal or plastic tube—one that won’t retain any air, which hastens the loss of flavor. The paste can be stored in the refrigerator with a shelf life of a few months. Wasabi powder will keep in its tin in a cool, dark place for several months too. As such, today, horseradish from Japan is exported as wasabi in the paste and powder format mixed with a little mustard, cornflour and food colouring.
Being able to get your hands on real wasabi would be a treat but the truth is, real wasabi is rare outside of Japan. Hence the product we most often use isn’t real wasabi—but it probably is the flavour we know and love. Wasabi paste today is used to compliment sushi, sashimi, and other Japanese dishes like soba noodles and added to salad dressings or even tempura batter. You can stir it into ketchup, mayonnaise, or guacamole for a hot spread or a spicy dip, or whisk it into soy sauce or make a marinade for beef.
We had the privilege of visiting a real wasabi farm in Nagano and it further deepened my understanding why real wasabi is so rare hence so expensive and hardly available outside of Japan.
Daio Wasabi farm (3640 Hotaka, Azumino, Nagano Prefecture 399-8303, Japan)
Daio Wasabi Farm is 155,000 sqm in size and it is the largest wasabi farm in Japan, producing 130 tonnes a year, 1/10 of the total Japanese production. The idyllic scene of old-fashioned, wooden water wheels alongside the river at the Daio Wasabi farm in rural Azumino City in Nagano just made wasabi that little more special. The farm has multiple large fields with a meticulously maintained network of small streams that constantly provides each wasabi plant with clear, flowing water from the Northern Alps. Only under such pristine conditions is wasabi cultivation possible. The farm is spread out over a wide area, with a restaurant, small shrines and shops linked by winding paths. It’s very peaceful and picturesque place to walk around. The whole area is surrounded by the stunning snow capped Japanese Alps. We were hosted by Wasabi Master Shigetoshi san, who is also the Chief Storyteller and Farmguide. I must say, our wasabi master is one hip and charming man that reminded me very much of Richard Gere.
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