A three-letter figure should be enough to bust the myth: E133. It is this dye that gives the neon green hue to the paste you spread on your sushi, not the Japanese root from which it supposedly takes its name. The true story of wasabi hinges on two numbers that answer each other: horseradish root costs on average 3 euros per kilogram, while a Wasabi Japonica root can reach 300 euros per kilogram. Between the two, an entire segment of the agrifood industry has chosen its side.
Key takeaways
- A three-letter colorant reveals why your wasabi has nothing to do with the Japanese root
- The real root takes two years to cultivate and costs €300 per kilo: here’s what you’re actually buying
- 95% of wasabi outside Japan is horseradish in disguise — even in restaurants with a reputation for authenticity
Why the real wasabi costs a fortune
Wasabia japonica is no vegetable you sow and forget. This plant thrives under remarkably precise conditions that long discouraged mass production outside its island home: wasabi is a rhizome-bearing perennial native to the archipelago, growing wild in the mid-mountain regions of Japan, in well-irrigated soil, under a cool, shaded climate. Consequently, one region accounts for the bulk of national production: the prefecture of Shizuoka, responsible for about 80% of domestic output, has specialized in cultivating a wasabi that remains fragile, slow to produce, and therefore costly.
Two years. That’s roughly the time it takes to obtain a usable rhizome, compared with a few months for ordinary horseradish that grows with little effort. This slow pace, combined with the requirement for pure, constantly circulating water, explains why some European specialty suppliers list dizzying prices: in December 2024, a Swiss online supplier offered around 750 CHF per kilogram, and 580 €/kg from a German supplier was not negligible either. Even in Japan, where the plant grows in its own climate, luxury remains the standard: some rhizomes are traded by the unit at prices that would make any sushi enthusiast pause.
What’s really in your tube
Turn the tube in your pantry, the one you squeeze almost automatically beside your soy sauce. The ingredient list never lies, unlike the label. On one of the best-selling products in major retail, the composition reads clearly: 31.7% horseradish, humectant E420, rice bran oil, salt, dextrin, only 4.5% Wasabi japonica, starch, water, flavor, turmeric, thickener E415, acidulant E330, and colorant E133. The root that gives the product its name barely plays a symbolic role, far behind the horseradish that does most of the flavor work.
This pattern is far from isolated. The majority of tubes sold in Europe follow the same dosage logic: horseradish dominates with 20 to 30% of the product, while wasabi barely reaches 1 to 4% and sits around the 5th position on the ingredients list. Some powdered references go even further, with such a minuscule trace of wasabi that it borders on homeopathy: a product sold commercially contains only 0.1% Wasabia japonica for nearly 90% horseradish powder. The Agrolab laboratory, which regularly tests these condiments, has even found extreme cases where the Japanese plant was completely absent from the recipe, while the packaging proudly displayed the word “wasabi.”
E133, the colorant that betrays the deception
Horseradish has a color problem: it is white. To resemble its Japanese cousin, it needs a chemical brushstroke. That’s where the infamous E133 comes in, often paired with turmeric or Tartrazine E102 to achieve that garish green that doesn’t exist in any natural plant. Tartrazine (E102) and Brilliant Blue FCF (E133) together yield this vivid green hue that no plant in nature possesses. One detail worth noting: this dye has a storied history in Europe. The use of this controversial additive, E133, the notorious Brilliant Blue FCF, was long banned in Europe and remains prohibited in several countries around the world, including Australia. Its safety has never been conclusively proven by research, but the fact that it remains banned with certain trading partners speaks volumes about the precautionary principle applied elsewhere.
The visual contrast between genuine and fake is striking once you know where to look. Real wasabi carries a pale, natural green, almost pastel, while the horseradish paste displays a bright, uniform green, a sign of colorants. The texture tells the same story: freshly grated root has a lively, grainy feel, whereas the industrial paste stays relentlessly smooth, as if frozen in time.
How to spot the real root among the imitators
The scale of the phenomenon goes far beyond a supermarket anecdote. More than 95% of wasabi consumed outside Japan is, in fact, a cheap imitation of a demanding and costly plant. In other words, nearly all sushi restaurants in France, including some establishments that pride themselves on authenticity, serve horseradish disguised as wasabi.
There are nonetheless simple cues to avoid being fooled. Tubes that bear the label “hon wasabi” tend to contain a more honest share of the actual plant, though they generally top out around 30%: tubes labeled “hon wasabi” are those with the highest Wasabia Japonica content, around 30% at most. The price also doesn’t lie: a tube made purely from real rhizome costs noticeably more than a supermarket imitation, even if the volume is often smaller. Beyond the budget, it’s a matter of mouthfeel: real wasabi is not aggressive; it accompanies. Its heat rises gradually, awakens the raw fish without overpowering it, whereas the industrial version burns the tongue and masks everything else. Next time you order sushi, a quick glance at the paste’s color and its price will reveal what the label tries to hide.
Sources: ericbur.fr | gourmet-versand.com
