Big in Japan: What Exactly is Wasabi?

Did you ever wonder what exactly that green stuff is that you smear on your sushi?

I mean, we all know that wasabi (わさび, 山葵) burns like a hell-spawned wildfire, and clears the sinuses with a fiery vengeance. But, where does it actually come from, and how can something so seemingly innocent be so unbelievably potent?

For starters, the best wasabi comes from Japan (no surprise there), most notably the Izu peninsula in Shizuoka prefecture. Much like American horseradish, wasabi plants grow naturally in stream beds, particularly where there is clean water that is free of impurities.

If you've ever had the pleasure of smearing just a tad too much of the stuff on your tuna roll, wasabi is a nasal irritant that is more comparable to hot mustard than it is to chili pepper. That wonderful little chemical that can have you rolling your head on the sushi bar is called an isothiocyanate, which coincidentally inhibits microbe growth.

Although there's no denying that wasabi brings out the flavors of sushi, it may have been traditionally added to raw fish in order to prevent it from spoiling.

Gallery: Japanese Food

Needless to say, you shouldn't eat raw fish unless you're absolutely confident in the quality of the fish. Just because sushi makes an appearance at an all you can eat buffet doesn't necessarily mean that you should eat all you can!

Interestingly enough, most Americans have never actually eaten real wasabi as the stuff sold stateside is usually squeezed out of a tube. In fact, this stuff actually doesn't even contain any real wasabi, and is usually nothing more than horseradish, mustard seed, and green food coloring.

Real wasabi, which I can assure you has no equal substitute, is sold in Japan in the form of a root.

Before it can be used, the wasabi plant is grated on a metal oroshigane (卸し金), which is a special kind of grater used solely for wasabi. Traditionally of course, the best graters were made of shark skin, and today upmarket sushi restaurants in Tokyo still grate wasabi according to this method.

Once the wasabi paste is prepared, it should remain covered until served in order to protect the flavor from evaporation. In case you were wondering, this is the actual reason why sushi chefs always put the wasabi between the fish and the rice.

Well, I hope this little lecture on wasabi has been informative. Now that you know exactly what wasabi is, go ahead and impress your friends with some wasabi trivia the next time you're sitting at a sushi bar.

Gadling again ;)