Research Tool Bench

Is Sushi-Restaurant Wasabi Actually Fake?

Last updated 2026-08-24

The little green paste next to a sushi roll gets credited with an eye-watering kick real wasabi is famous for, and lately with an eye-watering statistic too: dozens of food and travel sites now state, as settled fact, that 95 to 99 percent of the "wasabi" served in North America isn't wasabi at all. We went looking for where that specific number actually comes from — and for something more checkable than any blog's word for it: what the world's biggest wasabi-tube brand prints on its own ingredient list.

The claim

Most of the green paste served as "wasabi" at sushi restaurants — commonly cited as 95 to 99 percent of it — is not made from the wasabi plant, but is a substitute of horseradish, mustard, and green food colouring.

Source trail

Every current blog post repeating the "95 to 99 percent" figure that we traced leads back to the same place: a 15 October 2014 Washington Post article, "Why the wasabi sushi restaurants serve is almost never actual wasabi." We could not read that article directly ourselves — it returned a 403 both times we tried to fetch it this session, consistent with it now sitting behind a paywall. But a separate, independently reported piece, a 2015 Canadian Geographic profile that interviews the same figure on its own, corroborates who the number traces to: Brian Oates, president and chief science officer of Pacific Coast Wasabi, described by Canadian Geographic as heading "the largest commercial wasabi producer in the world outside Japan." The most-repeated statistic behind this whole claim comes from the head of a company that sells real wasabi — someone with a direct commercial stake in people believing what they're normally served is fake. None of the current blog posts we checked name Oates or mention that; nearly all of them cite "The Washington Post" instead, as if the newspaper had run its own independent count.

What's confirmed

What isn't

Verdict

The core claim holds up on evidence that doesn't depend on the number everyone quotes: the world's dominant wasabi-tube brand states on its own site that its product is mostly horseradish, and the plant it's named for is independently confirmed by two university extension services to be genuinely rare and difficult to grow outside Japan — a cheap substitute dominating the market is entirely plausible on those facts alone. What doesn't hold up to a source check is the specific number everyone attaches to the claim. "95 to 99 percent" isn't a study result or an industry audit; it's one wasabi-growing executive's estimate, reported once by a newspaper now behind a paywall, and repeated ever since by sites that cite the newspaper rather than the man whose company sells the alternative.

Same shape as our brief on Thomas Crapper and the flush toilet: a number everyone repeats with total confidence turns out to trace back to a single, less authoritative source than the confident retellings imply. Also related: the tongue map of taste zones, another case where a popular correction rests on research most retellings never actually read. More research briefs.