What is the true origin of wasabi? How is it related to horseradish?

Ha, that's a great question, and one that many people get confused about.

Simply put: The small packet of green "wasabi" you usually get at conveyor belt sushi restaurants or with sushi takeout is, nine times out of ten, not real wasabi, but an imitation made from horseradish.

Let me break it down for you:

1. Real Wasabi

   • It comes from a plant called "wasabi" (わさび). The part we eat is its rhizome (underground stem).
   • This plant is very particular about its growing environment; it must thrive by clear, flowing water. It's very difficult to cultivate, and yields are low, making it extremely expensive.
   • Fresh wasabi rhizome is light green. Before eating, it's freshly grated into a paste using a special sharkskin grater (or other grating tools). Its flavor is very unique; besides the pungency, it has a distinct fresh aroma and a hint of sweetness. The spiciness goes straight to the nasal passages but comes and goes quickly, feeling very refreshing and not leaving an uncomfortable burning sensation in the mouth.
   • Because it's precious and delicate (its flavor largely dissipates within 15 minutes after grating), you usually only find chefs grating fresh wasabi for you in higher-end Japanese restaurants.

2. Horseradish

   • This is another plant, somewhat resembling a white radish, and it's white. It's more common in Western countries, for example, as "horseradish sauce" served with steak.
   • Its taste is also pungent and stimulating, but much more "aggressive" and longer-lasting than wasabi, lacking the fresh aroma and layers of flavor.
   • Because horseradish is easy to grow and very low-cost, it has become the perfect "substitute" for wasabi.

So, their relationship is:

Wasabi (real wasabi) and horseradish (fake wasabi) are actually "cousins." They both belong to the Brassica family, and their chemical composition contains "isothiocyanates," which cause the pungent taste, thus providing a similar "nose-clearing" experience.

The tube or powder "wasabi" we usually eat is mostly made from ground horseradish, mixed with green food coloring and other seasonings. If you don't believe it, next time check the ingredient list; it will definitely say "horseradish," "wasabi flavor," or similar, and not "wasabi" or "Wasabi."

To summarize:

• Real Wasabi = Wasabi plant, expensive, fresh aroma, spiciness comes and goes quickly.
• Fake Wasabi = Horseradish + green coloring, cheap, aggressive, spiciness lasts longer.

Next time you go to a high-end Japanese restaurant, if you see the chef grating a green stick on a small board, congratulations, you're about to eat real Wasabi!