Is Wasabi a Horseradish?

Posted on 09 Aug 2014 00:10

Many people assume that Wasabi is a type of green horseradish, since it tastes something like horseradish and has the same nasal-clearing power.

Wasabi is often called Japanese Horseradish. As well, most of the wasabi served in the U.S. comes in a powdered form and is actually regular horseradish with some mustard and green coloring added.

However, although both Western horseradish and wasabi are members of the Brassicaceae family, which includes cabbage and mustard, wasabi is of a different genus. Horseradish is of the genus Armoracia and Wasabi is of the genus Wasabia. The scientific name for cultivated wasabi is Wasabia japonica, but it is often called Eutrema japonica. The wild species is Wasabia tenuis. The wasabi plant is unique to Japan and its name translates to "mountain hollyhock." The plant was found wild from the major Northern island of Sakhalin all the way South to the island of Kyushu.

Wasabi is a semi-aquatic perennial that is difficult to cultivate and likes to grow at the edge of cold streams, in marshy conditions. When it is cultivated, it is grown in flooded mountain terraces to get the cold and clear running water that it needs. It is still sometimes harvested in the wild, as well.

Wasabi has also begun being cultivated in North American and New Zealand. The roots are from 2 to 7 inches long and roughly covered with many light-brown "eyes." When sold fresh, are often kep in a shallow pan of water and misted to help maintain freshness. Fresh wasabi is very expensive and rare outside Japan, especially given ever-increasing demand, which is why only premium Sushi shops serve the real thing. Products sold in the West as paste or powder, are usually not true wasabi but a mixture of horseradish, green tint, and other ingredients, similar to that used in most sushi establishments.


Fresh Wasabi root grated with sharkskin samekawa grater.


Fresh Wasabi root grated with sharkskin samekawa grater.

Powdered Wasabi

Powdered wasabi comes in small round tins, somewhat like ground mustard. It is prepared by adding a small amount of lukewarm water and mixed until a smooth paste forms. It is then allowed to stand for 10 minutes, covered, to allow the flavor to develop. It is more possible to find real powdered wasabi than paste, but most products are made from horseradish.

Paste Wasabi

Paste wasabi comes in small plastic tubes. It is ready to use as is. Once the tube is opened and some of the wasabi is used, it must be resealed and kept in the refrigerator. The imitation products, both paste and powder, are widely available in well-stocked supermarkets.

Fresh Frozen Wasabi

Frozen wasabi is sold in airtight packages. It is made from fresh wasabi that is grated at a very cool temperature and then packaged and frozen immediately so that its flavor and freshness is maintained. It is only likely to be available at Japanese markets.

Flavor of Wasabi

Many people think that wasabi is much hotter than horseradish, but this is probably due to the wasabi substitutes they have been served, which sometimes have added mustard for pungency. In fact, true wasabi is more fragrant and not as sharp as its white horseradish relative. The hot part is contained in the inner part of the root.

Working With Wasabi

To use fresh wasabi, cut out the "eyes" and use a paring knife to trim away the tough brown skin until the light green flesh is exposed. Only trim as much of the root at you plan on using (some say there is no point in peeling). Rub on a fine grater using a circular motion. Japanese Sushi chefs use a sharkskin grater called samekawa oroshi ki. The sharkskin is actually from Angel shark. These are simply sharkskin mounted on a wooden or ceramic paddle and they make the best surface for grating the wasabi. These can be purchased but they will not last long and are probably impractical for most home cooks.

A microplane grater will probably not work as well, as they produce fine shreds of wasabi rather than a paste like result. There are, instead of sharkskin graters, fine steel, copper, or ceramic graters that can be purchased readily in the West.

The finer the paste, the more flavor and pungency you will get. Use quickly as wasabi loses its flavor fast. It is said that the best time to use freshly grated wasabi is about 10 minutes after preparation and that the flavor peaks after about 20 to 30 minutes. After that flavor starts to diminish. Mixing the paste may renew the flavor somewhat. Use powdered wasabi according to package directions, and use the paste or thawed frozen wasabi (thaw in fridge) just as you would freshly grated.

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