What is Wasabi? (The Answer Will Surprise You.)

What is Wasabi?

Most of us think we’ve tried wasabi. It arrives in a tidy green dollop beside sushi—sharp, sinus-clearing, almost fluorescent in color. But chances are, what you’ve tasted isn’t wasabi at all.

Most of the wasabi served in restaurants around the world is an imposter: a blend of horseradish, mustard powder, and green food dye. The real thing? Fresh wasabi is rarer, more complex, and infinitely more captivating.

To understand wasabi is to understand a small, ancient corner of Japan. It’s where water runs cold and pure, moss carpets the forest floor, and farmers work in quiet communion with the land. It’s here—in the shaded riverbeds and spring-fed valleys of Izu—that true wasabi (Wasabia japonica) grows. Cultivated with meticulous care, this plant offers not just a flavor, but a window into Japan’s culinary philosophy, history, and reverence for nature.

On our chef-led journey through Japan with David Utterback or Lee Anne Wong, you’ll visit a wasabi farm where tradition and terroir meet. In doing so, you’ll discover why this humble root has become one of the most prized ingredients in Japanese cuisine.

What Is Wasabi Made Of? A Botanical and Cultural Rarity

The wasabi plant belongs to the Brassicaceae family, which includes mustard, horseradish, and cabbage. But unlike its spicy cousins, wasabi is notoriously difficult to grow. The plant requires a very specific environment: cool, clean, running water, partial shade, and mineral-rich soil. Even under ideal conditions, it takes 12 to 18 months to reach maturity, and the yield can be heartbreakingly low.

There are two main cultivated varieties: Daruma and Mazuma. Both are used in traditional Japanese cuisine, but regional climate, water quality, and soil conditions give each root its own nuanced flavor profile—much like wine grapes.

What sets real wasabi apart isn’t just the peppery heat (which dissipates quickly, unlike the lingering burn of horseradish), but its vibrant complexity. A freshly grated wasabi rhizome has notes of sweetness, vegetal freshness, and even a hint of floral aroma, balanced by a clean heat that enhances, rather than overwhelms, the dish.

From Temple Tables to Sushi Counters

Wasabi has been a part of Japanese cuisine for over a millennium. Early records show that it was first cultivated in the 10th century, primarily for its medicinal properties. Known for its antibacterial qualities, it was originally served alongside raw fish not for flavor—but for health.

Over time, its culinary value eclipsed even its medicinal use. In Edo-era Japan, wasabi became a staple in sushi preparation—not only for its flavor, but for its symbolic role in balancing harmony and contrast, a central tenet of Japanese aesthetics.

Today, real wasabi remains a coveted luxury, used sparingly and with great respect. It is grated fresh on a sharkskin paddle called an oroshi, releasing its delicate compounds moments before eating. Within 15 minutes, the flavor begins to fade, a reminder of impermanence—and why the freshest wasabi is always reserved for the finest meals.

Water Farming in Japan’s Mountain Valleys

On our journey to Japan, we visit a wasabi farm nestled in Izu, a place where the air is crisp, and the rivers are so clear you can see every pebble lining the streambed. These farms are unlike any traditional agricultural fields—they are tiered, stony plots carved into mountain slopes, fed by cold, continuously flowing spring water.

Wasabi grown in water (called sawa wasabi) is considered the highest quality, but it’s also the most demanding to cultivate. Each plant is hand-planted in carefully arranged gravel beds, which allow water to pass gently over the roots. Too much sun or stagnant water can kill the crop; so can a single shift in temperature.

As you walk through the farm, the air is laced with the scent of damp earth and river moss, and the sound of trickling water is constant. It’s a deeply serene experience—one that speaks to the patience and precision behind each wasabi root.

What Real Wasabi Tastes Like

Once harvested, the rhizome—a thick, knobby stem—is gently cleaned and trimmed. Rather than being sliced or pureed, wasabi is grated into a fine paste just before serving, using a rough surface traditionally made from dried sharkskin, though modern ceramic and metal graters are also used.

The paste is never stored. It’s grated to order, typically forming a small mound next to nigiri, soba, or sashimi. The flavor is sharp but fleeting, designed to complement raw fish, not overpower it. In fine dining settings, it’s also used in dressings, marinades, or to add subtle brightness to grilled meats.

And yet, despite its culinary pedigree, most diners worldwide have never tasted the real thing. Instead, they’re served an industrial substitute—an inexpensive, mass-produced blend of horseradish, mustard, and dye. Tellingly, this imitation product is often labeled wasabi simply out of convention. In truth, only a tiny fraction of global wasabi is authentic, and most of it never leaves Japan.

Visiting a Wasabi Farm on Our Japan Trips

One of the highlights of our Japan itinerary is a guided walk through a working wasabi farm, where guests meet the farmers, learn about traditional water cultivation methods, and—most importantly—taste wasabi at its source.

It’s a moment of quiet awe. You stand among the plants, sunlight dappling the forest floor, water gliding over your boots as it weaves through the beds. A farmer lifts a rhizome from the stream with gentle reverence, and soon after, you’re holding a freshly grated mound of wasabi on a ceramic dish.

For many, this is the first time tasting real wasabi—and the realization is profound. It’s not the nostril-searing burn of your local sushi spot, but something more refined: a flash of brightness, a whisper of heat, a clean finish that lingers like memory.

Why It Matters: Flavor, Philosophy, and the Art of Attention

Understanding what wasabi is—and what it isn’t—is about more than correcting a culinary misconception. It’s a lesson in place, precision, and patience. True wasabi reflects the ethos of Japanese cuisine: a reverence for ingredients, an obsession with freshness, and a belief that food is most powerful when rooted in context.

It reminds us that taste is tied to time and place, and that some of the world’s most exquisite flavors are born from the quiet work of those who listen closely to the land.

Experience the Real Thing in Japan

If you’ve only ever known wasabi from a squeeze tube, this trip will change everything. Join us for an unforgettable journey through Japan, where you’ll not only taste real wasabi, but understand the care, culture, and centuries that brought it to your plate.

Book your culinary journey through Japan.