What is wasabe made of?!
Answers: Apparently there is 'fake' wasabe which is widely used that's made of horseradish. And then 'real' wasabe is very expensive. But what's it made of?
Wasabia japonica, is a member of the Brassicaceae family, which includes mustard, horseradish and cabbages.
So to answer your question It is the root of the Wasabia plant.
In other words Wasabi is made of wasabi
It is a rhizome. And you're right. Most of the wasabi that we get commercially is "fake" and made of horseradish, food coloring, and I believe flour.
Wasabi is a plant, like horseradish. The stuff you get in restaurants has probably been mixed with horseradish. I just know it's too hot for me!
All of the respondant have a good point, but as a former chef and someone who has worked in Japan, and used fresh, it is expensive there, and is now grow in Washington State and B.C Canada as a cash crop.
It was originally a wild root, and is a rhizome like ginger, potatos, strawberrys and other product that send out shoots to produce more plants, the fresh stuff is far superior to the dried or powdered, and the ones in tubes like toothpaste I have found lose there kick after time, I have never heard of fake wasabi, horseradish is a root like a knobbly carrot, you peel it and grate like cheese and add some vinegar or add it to sour cream for a dip, it t could be grated, dried and pulverized, coloured green and sold as a wasabi, but they have 2 very different tastes.
Fresh hits you hard in the mouth & throat, the powdered tends to hit you in the back of your mouth at your sinus cavity like hot sauce, if you can ever find a real piece, I get it here in Canada, give it a try.
Grated Japanese horseradish. Only very expensive Japanese restaurants use fresh wasabi. Everyone else uses powdered (reconstituted at home with a little warm water), or prepared (in squeeze-out tubes like toothpaste).
My step-father, a former Sushi Chef, said that real Wasabi is actually made from a Wasabi root type of plant called Rhizome, costing about $100/lb (about $8 per root). Most sushi restaurants here in the U.S. use the imitation kind, made from horseradish. The real Wasabi does NOT have that fiery sinus-clearing effect, but rather have a sweet after-taste. Since it's mostly available in Japan, my step-father used to go to the airport once a week to pick up the fish supplies and real Wasabi, imported directly from Japan for his sushi restaurant.
horseradish...horseradish...horseradish....
Rhizome plant.
I wrote about it in my website for some more details and an short clip on the real thing.
The real wasabi is just the gratings of the Rhizome plant and should not look like a green toothpaste.