Sorry, But That's Not Really Wasabi
That green paste beside your yellowfin tuna is more than likely a fraud.
The next time you and friends go out for sushi and sips of sake, drop another type of bomb on them: that pistachio-green paste smeared between the fish and rice on their sashimi is not actually wasabi. Neither is the dollop of green goo on the platter of sliced rolls.
(Prepare yourself for the incredulous looks now. They’re coming.)
Truly, that green paste with a punchy hit of spice that can burn oh-so-good deep inside your head is not real wasabi. Truth be told, you likely haven’t eaten any real wasabi ever. Neither have your friends.
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The overwhelming majority of “wasabi” (read: 99 percent) served at most restaurants and available in grocery stores in the U.S. is almost always a mixture of horseradish, hot mustard, and food coloring. Some products have chemicals and stabilizers like cornstarch added, too. Few have any real wasabi.
Authentic wasabi rhizome has a much more nuanced flavor than the wasabi you’re accustomed to eating. It still packs a punch, but it has a hint of green herbal flavor with a whisper of sweetness. It’s a much better pair to delicate fish than the tongue-torching wasabi we eat, if being we’re honest.
Like horseradish, wasabi is grated over a fine plane, or more traditionally a shark skin paddle. But the flavor of real wasabi is short-lived. Most chefs won’t grate the rhizome until your meal is ready to be served. That’s because the potent flavor molecules in wasabi fade quickly; in as little as 15 minutes, most of the wasabi flavor will be gone.
Horseradish is more potent to begin with, so even with some fade, it remains pungent. Plus, the wasabi you eat with your spicy salmon roll likely started out as a powdery mix, which is much more shelf-stable. Chefs reconstitute the dried combo of horseradish and mustard powders with water just before plopping a plug of the spicy condiment on your plate.
Even if you ask, you’re unlikely to find real wasabi at your local sushi spot, and you might not even find it in sushi restaurants in Japan.
That’s because real wasabi, which is made from the grated stem of the Wasabia Japonica plant, is a bit finicky and difficult to grow. Unlike horseradish, which is hearty and flourishes almost unattended, wasabi can only grow in a moist environment at specific temperatures (think: the chilly streams of some mountainous Japanese regions). The rhizomes must be hand harvested, too, and mass planting is a recipe for disaster: the plants easily rot and share diseases when so tightly packed.
That doesn’t mean wasabi is an all out impossible food to find. A small handful of farms in North America grow wasabi; they’re mostly in the U.S. Pacific Northwest and Canada. They can ship wasabi rhizomes to you in fresh form (they last about four weeks), or some sell other options like wasabi powder and wasabi salt.
You’ll just need to be prepared to pay—which is the second reason you’re unlikely to find real wasabi on your platter. At TheWasabiStore.com, a pound of wasabi rhizome is $100. That would make a ball of wasabi for your sushi, conservatively, at least five dollars. Most people wouldn’t be prepared to pay extra for something they don’t realize is legitimately a better product when the fake stuff isn’t wholly unapproachable.
If you ever have the opportunity to eat real, freshly-grated wasabi, whether with your sushi or any other dish, do so. It’s an entirely different experience than the green goop you normally eat—not that we’re complaining. We do love that burn.