Wasabi is the plant of Brassicaceae Wasabia. It is an indigenous plant of Japan. It's an edible plant. It has a uniquely strong, pungent taste and is known worldwide as a spice native to Japan.
Its botanical name is Wasabia japonica or Eutrema japonica, the latter of which is used when Wasabia is included in Eutrema. Though there are many cultivars, W. japonica var. Daruma and W. japonica var. Mazuma are the major ones.
It is sometimes called hon-wasabi (real wasabi) in order to distinguish it from other closely related plants that are also referred to as wasabi, particularly horseradish.
In ancient times, the word "wasabi" appeared in "Fuyaku ryo (tax structure)" (the equivalent of Enforcement Order of Corporation Tax Act), which was issued in 718 during the Nara period. It is thought that wasabi was delivered as a special local product and used as a medicine.
In the Muromachi period, wasabi was already used as a spice in the same way it is today. In the Edo period, it became popular among ordinary citizens in keeping with the spread of sushi and soba (buckwheat noodles). Although people picked and used wild wasabi in the old days, the villagers of what is now Utogi, Aoi Ward, Shizuoka City, started to cultivate wasabi in the Edo period. It is believed that the above triggered the spread of wasabi cultivation.
The wasabi cultivated at Utogi was presented to Ieyasu TOKUGAWA, who then resided at Sunpu Castle and presided over politics as Ogosho (the shogun's father who holds real power), and won his highest praise. Further, as the wasabi leaf resembles the crest of the Tokugawa family "Aoi" (hollyhock), wasabi cultivation was protected by the bakufu (shogunate government). On the other hand, the cultivation technique of wasabi was classified as strictly confidential and it was prohibited from spreading such technique to other regions.
In 1744, Kanshiro ITAGAKI, who served as the guardian of the mountains at Amagiyugashima (Izu City), visited Utogi at the behest of Mishima's local governor for the purpose of teaching the technique of shiitake mushroom cultivation. Itagaki implored the local residents of Utogi to allow wasabi cultivation in Amagi, and the residents gave him seedlings of wasabi as a reward for his instruction in shiitake cultivation, though it was in violation of the law. Thanks to Itagaki's efforts, wasabi cultivation started at Amagi also.
The principal production centers of wasabi in Japan are the prefectures of Shizuoka, Nagano, Tokyo, Shimane, Yamanashi, Iwate, etc. Wasabi is also produced in Taiwan, New Zealand, the People's Republic of China and elsewhere.
The best brand of Wasabi is Mazuma, which is produced in Shizuoka Prefecture and is characterized by its pungency and strong sweetness.
The wasabi flower is the official flower of Izu City and Azumino City, which are the production centers of wasabi.
Generally speaking, the cultivation methods of wasabi are categorized into mizuwasabi (water-grown wasabi) (sawa wasabi), which is cultivated in water, and hatawasabi (farm-grown wasabi) (rikuwasabi), which is cultivated in the field. Mizuwasabi is either cultivated on wasabi farms that use the water of waterways or mountain streams, or it grows naturally and is eaten raw. Hatawasabi is used for the production of "wasabizuke (wasabi preserved in sake lees)," a product made by mixing the leaves and stems of wasabi with sake lees, since its size is small.
While the root of Mizuwasabi is large, hatawasabi and autochthons have small roots. The above results from the effects of allyl isothiocyanate, which is emitted by the root of wasabi. This substance kills bacteria in the surrounding soil and hinders the growth of other plants that require bacteria in their roots. However, wasabi itself is affected by this substance and is not able to grow bigger (self-poisoning). Contrastingly, Mizuwasabi can grow larger, since allyl isothiocyanate is washed away amid the running water and permeable soil.
In cultivating mizuwasabi, abundant fresh water whose temperature is 9 to 16 degrees Celsius, as well as permeable soil (such as sandy soil), is indispensable; moreover, strong sunlight must be avoided. Though neither fertilizer nor labor is required in cultivation, it is known as a kind of farm product whose cultivation is difficult because it can only be cultivated in a place where abundant fresh water is available. It is sometimes cultivated on a small scale by utilizing the water of streams or other waterways in mountainous areas.
There are two kinds of wasabi: the one with a red stem and the one with a green stem. Because wasabi is a plant of Brassicaceae, like cabbage, its leaves are sometimes eaten by cabbageworms (green caterpillars).
The pungent ingredients of wasabi are allyl isothiocyanate (6-methylisohexyl isothiocyanate, 7- methylthioheptyl isothiocyanate and 8-methylthiooctyl isothiocyanate), etc. It also has the effect of killing bacteria.
The pungent taste of wasabi is created when synigrin, which exists in wasabi's cells, reacts with enzymes during the process of grating. It is completely different from capsaicin, the pungent ingredient found in chili peppers.
Uses and methods of processing
The underground root of wasabi is used, after grating, as a seasoning for sushi, sashimi (sliced raw fish), chazuke (boiled rice with tea) and soba. Because it has the effect of killing bacteria, it's recommended as an accompaniment for foods that are eaten raw.
Taking advantage of allyl isothiocyanate's action of killing bacteria as well as controlling the emission of ethylene gas, which promotes the aging of plants, wasabi is also used for antibacterial goods and deodorants, and in freshness-preserving agents for food/vegetables kept in refrigerators.
One can enjoy ohitashi (boiled vegetables) with the pungent taste of wasabi by boiling wasabi's the leaves and stems slightly and preserving them in an airtight container for a while.
Shoyuzuke, which consists of wasabi leaves and stems bottled together with soy sauce, is also available. It can keep for a long period and is used as a food served with tea, as a relish or as a "nibble" accompaniment to drinks.
Wasabizuke, a specialty of Shizuoka Prefecture that's produced by pickling finely cut underground roots together with sake lees, is used as a nibble for drinks as well as a topping on boiled rice. In the mountainous area of Shimane Prefecture, Uzumemeshi, a kind of shirukakegohan (boiled rice with soup) that has the taste of wasabi, is available.
As wasabi-flavored foods, chilled sweets (soft ice cream and ice cream) and rice biscuits (rice cookies and small rice cookies) are also sold.
Because the pungent taste of wasabi is emitted only through exposure to oxygen, the recommended grater is one that can finely mash the cells, such as one made of shark skin. Also, it is commonly said that a grater made of metal should be avoided because of its incompatibility with wasabi. However, many Japanese restaurants and sushi bars use narrow-bladed metal graters.
As the flavor of wasabi, especially the pungency, is volatile, such flavor could evaporate if grated wasabi is left as it is for a long time. However, wasabi is normally not used soon after grating because it's too pungent. Some sushi bars provide clients with a stem and a grater so they can grate it as desired. However, the purpose of the above is merely to give the "freshly grated" feeling.
Also, when wasabi is dissolved in soy sauce nearly all its flavor evaporates and becomes less perceptible. Therefore, it is said that a person who eats sashimi topped with a small quantity of wasabi not soaked in soy sauce is an expert.
Generally, children dislike the unique pungent taste of wasabi, which stimulates their noses strongly. Therefore, sushi without wasabi--called "sabinuki"--is provided for children and other people who don't like wasabi.
Contrastingly, there is "wasabimaki (namidamaki)," a kind of sushi roll that is made of boiled rice and wasabi only and prepared in the same fashion as a tuna sushi roll. However, since high-quality boiled rice and wasabi are required in preparation, it isn't available at ordinary sushi bars or is served only to regular clients. When eating it, however, considerable resolve is required even for the person who likes wasabi, because a large amount of it is used.
When you feel an overly strong stimulation in your nose, you can soon be released from the discomfort by breathing deeply through your nose, since the substances stimulating your nose can be evaporated by doing so.
Wasabi is an allergenic food.
Wasabi in the broad sense
Plants that have the "wasabi" name
Some plants that have a similarly pungent taste are also called wasabi. However, they aren't necessarily closely related to wasabi.
Horseradish (western wasabi), wasabi daikon (wasabi radish), Armoracia rusticana
Yuriwasabi (lily wasabi), inuwasabi (dog wasabi), Wasabia tenuis syn. Eutrema tenuis
Wasabinoki (tree of wasabi), Moringa spp.
They are remote from wasabi.
Powdered wasabi and kneaded wasabi
Today, canned powdered wasabi as well as tubes of kneaded wasabi are sold, and these products are commonly used at home. Wasabi daikon or horseradishes with little flavor, colored green, are often used as the ingredients of these products.
Some of these products contain honwasabi. Because the underground roots of wasabi aren't suitable for preserving, other parts of wasabi are normally used for these products. When the ratio of honwasabi is 50% or more of the total content, the products concerned can be displayed with "honwasabi is used"; however, when the ratio is less than 50% the products concerned should be displayed with "containing honwasabi."
These products are used as preservatives for bento (box lunch) and insect repellents for rice, since they have bacteria-killing action.
The word "wasabi" is sometimes used to represent the sadness of adults based on the fact that even adults shed tears when the pungency of wasabi is too strong, since the pronunciation of wasabi is similar to the combination of wabi (simple elegance) and sabi (refinement); moreover, children dislike wasabi and its taste can only be appreciated by adults.