Wasabi
WAH-sah-bee
Eutrema japonicum
Sharp, nasal, fresh, fleeting heat.
What it is
Wasabi is the rhizome of Eutrema japonicum, a plant that grows in cold mountain stream beds in Japan, with a sharp, clean, nasal heat much like horseradish but greener and more fragrant. Its defining trait is how quickly it fades: freshly grated wasabi loses its punch within minutes, which is why it is grated to order. True wasabi is difficult to grow and expensive, so most of what is sold as wasabi paste or powder outside Japan is dyed horseradish with mustard. It is the classic partner to sushi and sashimi and seasons noodles and dressings.
Similar but different
Easy to mix up, different enough that swapping changes the dish.
- Horseradishsharp, hot, nasal, pungent.
Compare head to head
What it pairs with
Goes wrong with: dishes where the heat would not be used at once.
Common in Japanese cooking.
Whole vs ground
Real wasabi is grated fresh from the rhizome just before eating, since its heat fades within minutes. Most tube and powder wasabi is dyed horseradish and mustard.
How to handle it
Grate the fresh rhizome finely and use within minutes, before the heat dissipates. There is no need to cook it; it is a fresh condiment.
Storage
Fresh rhizome keeps in the fridge wrapped in damp cloth for a couple of weeks. Powder keeps dry; paste keeps refrigerated.
Buying note
Real wasabi is rare and costly; check the label, since most paste is horseradish dyed green. Fresh rhizome is the real thing.
Classic dishes
sushi, sashimi, soba, wasabi dressing.
Out of wasabi? Substitutes
No substitute is exact. These are the closest by flavor behavior, with the ratio to start from and how the result will differ.
| Use instead | Ratio | How it differs |
|---|---|---|
| Horseradish | use a bit more | the same nasal heat, less green and fresh; this is what most fake wasabi is |
One odd thing
Freshly grated wasabi loses its heat within minutes, which is why it is grated to order and why imitations dominate outside Japan.