What is Wasabi?
As one of the most prized crops from Japan, this pale green root is grown in cold mountain streams under some of the most closely guarded growing practices in agriculture. Many outside Japan have gone to great lengths to duplicate its wonderfully hot flavour. In fact, most of the commercial wasabi products in the west are fake. Many of us believe wasabi is the eye-watering and sinus-scouring vivid green side dish paste served with sushi, however, most of the time it is a concoction of horseradish, mustard, and artificial colouring.
Wasabi a member of the cruciferae family originating in Japan and is related to cabbages. It is a perennial which grows about knee high, is semi aquatic and produces a thickened stem in a similar fashion to a small brussel sprout. As the stem grows the lower leaves fall off. This stem has a very pungent smell and flavour when made into a paste. The fresh is certainly preferable, but in the West, it’s more commonly found as a dry powder. Premixed pastes are available but none capture the intensity well. Make your own paste from the powder or fresh root.
Preparation and Storage
Treat the fresh root like horseradish, shredding only as much as needed. Traditionally, a sharkskin grater or “oroshi” is used. Using sharkskin as a tool for grating wasabi has been a practice in Japan since the earliest times, and is still regarded as the preferred method of obtaining the best flavour, texture and consistency in freshly ground wasabi.
If a sharkskin grater is not available, ceramic or stainless steel surfaces can be used. Ceramic graters with fine nubs are preferable to stainless steel, but in either case, the smaller and finer the ‘teeth’, the better. Pulsing in a food mill pure will yield a fiery paste, or it can be tempered with other ingredients to make vinaigrettes, mayonnaise or other hot condiments.
Grating wasabi releases volatile compounds, which gradually dissipate with exposure to the air. Using a traditional sharkskin grater and keeping the rhizome at a 90-degree angle to the grating surface generally minimizes exposure to the air. In this way, the volatile compounds are allowed to develop with minimal dissipation. Once you have grated enough for the first ‘session’, pile the grated wasabi into a ball and let stand at room temperature for a few minutes to allow the flavor and heat to develop. The flavor will dissipate within a short period, so grate only what will be used within 15 or 20 minutes.
• Rinse the rhizome under cold running water.
• Scrape off any bumps or rough areas along the sides.
• Scrub the rhizome with a stiff brush.
• Cut the rhizome just below the leaf base and inspect the exposed flesh to ensure that it is a uniform green colour.
• Grate the cut end against the grater surface, using a circular motion.
• After use, rinse the rhizome under cold running water.
If you are using a sharkskin grater, rinse it under cold running water as well and let it air dry If you have powdered wasabi, make sure to allow some time once it is rehydrated so that the flavour compounds come back to the surface. Wasabi powder is very convenient for use and storage, when sealed in an air-tight container or bag, and stored in low temperature, the self-life is almost 2 years.
The pungent flavour of Wasabi lends itself to a great range of culinary uses. For most people the first introduction to its splendid taste is as a condiment for use with Japanese dishes such as Sushi, Sushimi and Soba dishes, and also with raw fish. For these uses it is ground up into a paste for seasoning. Increasingly, we are finding that the use of wasabi extends beyond the scope of these traditional dishes. It is a flavour in its own right and can be used to enhance dips, meats and other foods.
Wasabi Health Benefits
Besides its unique role as a food condiment, Wasabi also possesses many potential health benefits. A number of studies have shown that the active ingredients in Wasabia japonica are able to kill a number of different types of cancer cells, reduce the possibility of getting blood clots, encourages the bodies own defences to discard cells that have started to mutate, and acts as an anti-bacterial and anti-fungal agent against food poisons.
Wasabia Japonica owes its flavor and health benefits in part to a suite of isothicyanates (ITC’s) with unique characteristics including powerful anti-bacterial properties, which help mitigate microbial elements or pathogens potentially present. This helps reduce the effects food poisoning, supports detoxification and helps prevent conditions that lead to tooth decay. Rich in beta-carotenes and glucosinolates, wasabi also kills some forms of E-Coli and Staphylococcus.
Studies also indicate it helps reduce mucous, which has made it the focus of experiments relating to its use in combating asthma and congestive disorders. The unique ITC group found in wasabi includes long-chain methyl isothicyanates which are uncommon in most American’s diets. Long-chain methyl ITC’s have proven efficacy and potency in supporting natural liver and digestive detoxification functions than other more common types of isothicyanates.
The powerful antioxidant characterisics of wasabi are also attracting additional scientific study. Evidence suggests that glucosinolates and their hydrolysis products are efficacious in reducing cancer risk by encouraging the immune system to discard mutagenic cells.
Plant Description and Cultivation
Wasabia japonica is a slow growing perennial with a rooted, thickened rhizome, long petioles and large leaves. The wasabi rhizome looks much like a brussel sprout stalk after the sprouts are removed. The long stems (petioles) of the Wasabia Japonica plant emerge from the rhizome to grow to a length of 12 to 18 inches and can reach a diameter of up to 1 ½ inches. They merge into single heart shaped leaves that can reach the size of a small dinner plate. Wasabia Japonoica plants can take as much as three years to reach maturity. Initially, given the right conditions, the wasabi plant produces robust top and root growth, growing to about 2 feet with an overall width about the same.
After this initial establishment phase the rhizome begins to build and store reproductive nutrients, reaching a size of 6 to 8 inches in approximately two years. Under optimum conditions, Wasabia Japonica will reproduce itself by seed, though on commercial wasabi farms, plant stock is typically extended by replanting small offshoots which characteristically occur as the plant matures.
Wasabi prefers the cool, damp conditions found in misty mountain stream beds. It generally requires a climate with an air temperature between 8°C(46°F) and 20 °C (70°F), and prefers high humidity in summer. It is quite intolerant of direct sunlight so it is grown beneath a natural forest canopy or man-made shade. Wasabia Japonica grows in northern Japan, parts of China, Taiwan, Korea and New Zealand. In North America, the rain forests found in British Columbia, the Oregon Coast and in parts of the Blue Ridge Mountains in North Carolina and Tenessee provide the right balance of climate, sunlight and water quality to grow natural wasabi. Limited success has been achieved by firms using greenhouse and/or hydroponic techniques, but the resulting costs are typically quite high.
There are two main strategies that are used in growing wasabi. The higher quality wasabi, both in appearance and taste, grows in cool mountain streams and is known as semi-aquatic or “sawa” wasabi. Wasabi known as field or “oka” wasabi is grown in fields under varying conditions and generally results in a lower quality plant, both in appearance and taste.
French: Raifort du Japon
German: Bergstockrose, Japanischer KrenKorean: Kochu-naengi, Gochu-naengi, Gyeoja-naengi, Kyoja-naengi
Thai: Wasabi Chinese (Cantonese): Saan kwai
Chinese (Mandarin): Shan kui
Wasabia japonica Fam: Brassicae