What Is Wasabi?

Plus, how to tell whether the wasabi you’re eating is imitation.

June 23, 2022
Variety of sushi on a tray with chopsticks and soy sauce on stone background


Variety of sushi on a tray with chopsticks and soy sauce on stone background

Photo by: Claudia Totir/Getty Images

Claudia Totir/Getty Images

By Layla Khoury-Hanold for Food Network Kitchen

Layla Khoury-Hanold is a contributor at Food Network.

In the U.S., you might know wasabi as the spicy, bright green paste that accompanies your favorite sushi order. But what is wasabi and where does it come from? And is it true that there’s imitation wasabi? To answer all our spicy wasabi-related questions, we consulted Pascale Yamashita, a recipe developer, food stylist, food photographer and avid food lover based in Japan.

What Is Wasabi?

Wasabi, also known as Japanese horseradish, is a plant that belongs to the Brassicaceae family. People often consider wasabi to be the root of the plant, but it is actually a rhizome, a fleshy, underground root-like stem located between the wasabi plant’s leaves and its thin roots. The rhizomes are grated and served fresh. In Japan, grated wasabi is a popular condiment that’s typically enjoyed with sashimi and sushi alongside soy sauce for dipping.


Photo by: Makiko Tanigawa/Getty Images

Makiko Tanigawa/Getty Images

Where Does Wasabi Come From?

Wasabi is mainly grown in the Shizuoka, Nagano and Shimane prefectures in Japan. Wasabi is either grown in stream beds or in wet fields in mountain valleys. Japanese people consider wasabi farming areas to have the purest water since wasabi only grows where the water quality is high. Wasabi takes one and a half to three years to reach harvest, depending on how it is grown. It can be harvested throughout the year but is at its peak from November to February, when its flavor is the strongest. The wasabi plant’s flowers are also edible and typically sold from January to March in Japan.

Outside of Japan, wasabi is grown in parts of China, Taiwan, Korea, New Zealand and in certain parts of North America, including the Oregon Coast and parts of the Blue Ridge Mountains in North Carolina and Tennessee.

What Is In Wasabi?

Yamashita shares that fresh wasabi is more flavorful than imitation wasabi and is also less hot than imitation varieties. In Japanese grocery stores, a variety of imitation wasabi brands are sold which are typically packaged in tubes. Powdered wasabi is also available here, which consists of processed horseradish and green food coloring. The fresh wasabi plant is available at Japanese grocery stores but is not as widely available as imitation wasabi and is much pricier. Ready-grated wasabi is not available; once it is grated, wasabi is highly perishable and subject to diminished flavor.

What Does Wasabi Taste Like?

Wasabi is usually described as hot with a spicy flavor like horseradish or hot mustard. But different parts of wasabi taste different. The top part (near the leaves) is brighter green in color and contains more moisture than the bottom part; it tends to be more flavorful than hot. The bottom part is a pale, almost white-green color; it is less flavorful but packs more heat. The middle part of wasabi is well-balanced between flavor and heat. In Japan, some sushi chefs grate the top and bottom parts of fresh wasabi and mix them together to balance the flavor.

How Hot Is Wasabi?

Wasabi tastes spicy, but it isn’t hot in the same way chili peppers are. Chilis stimulate the palate whereas wasabi stimulates the nose. This is because the peppers’ spiciness comes from its capsaicin content, whereas wasabi’s pungency comes from a chemical compound called allyl isothiocyanate (it’s also what makes mustard, horseradish and cabbage spicy). When you eat wasabi, the sensation registers as a nasal-clearing burst of heat that dissipates quickly. Since wasabi doesn’t contain capsaicin, it can’t be compared to peppers using Scoville units as a measurement. Wasabi possesses a unique spiciness, but horseradish or hot mustard are the most comparable.

Wasabi is the grated rhizome of the wasabi plant. Prepared wasabi paste, also known as imitation wasabi, is what is sold in grocery stores and on most restaurant menus in the U.S. To mimic the flavor and color of wasabi, prepared wasabi paste typically contains horseradish, mustard powder and green food coloring.

I have grated wasabi in Izu Peninsula.food touring sightseeing


I have grated wasabi in Izu Peninsula.food touring sightseeing

Photo by: d3_plus D.Naruse @ Japan/Getty Images

d3_plus D.Naruse @ Japan/Getty Images

Real Wasabi vs Imitation Wasabi

The main difference between real wasabi and imitation wasabi is the type of plant used. Fresh wasabi is grated from the actual wasabi plant. Imitation wasabi is a paste made from processed horseradish, along with mustard powder, green food coloring and other additives. Imitation wasabi is more readily available than fresh wasabi in the U.S. and can be found at most grocery stores, Asian markets and online. Real, fresh wasabi can be purchased via specialty online retailers.

Is Wasabi Good for You?

Yamashita reports that in ancient Japan, the nobles and Shoguns consumed wasabi for its antibacterial properties to help prevent food poisoning. It was also used as a preservative to keep food from spoiling. Today, science confirms that wasabi is rich in antibacterial properties, but the claims that it can prevent food poisoning have yet to be substantiated. Wasabi is believed to have anti-inflammatory properties and to help reduce the risk of stroke, heart attacks and cancer, although these claims require further scientific study for validation.

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