Wasabi The Japanese horseradish

Welcome to a detailed insight into the fascinating world of Wasabi. In this post, you will learn everything there is to know about this Japanese root – from its botanical classification, the different varieties and cultivation methods to its culinary uses, pricing structures, and health-promoting properties. We place great emphasis on a factual, informative style, in which personal experiences are not missing.

Botanical Basics

Wasabi, often also called "water horseradish," belongs botanically to the cruciferous family. Unlike traditional horseradish, where mainly the root is used, in wasabi the so-called rhizome is predominantly utilized. The green, slightly knobby root requires plenty of clean water to grow optimally – a feature that makes its cultivation extremely demanding. The typical pungency of wasabi is due to mustard oils, which, when consumed, especially irritate the nasal mucous membranes. That is why you often feel a sharp pain in your nose if you have too much wasabi. In comparison, the heat of chili peppers comes from capsaicin and affects the body differently.

Varieties and Variations

The wasabi varieties cultivated in Japan differ in appearance, taste, and growth duration. Here we introduce the most important variants:

True Japanese Wasabi (Hon-wasabi)

Under the scientific name  Wasabia japonica  , true wasabi is classified. Its known variants include:

真妻種 (Mazuma-shu)

This variety is characterized by reddish-purple stems and roots. When grated, it releases an intensive aroma with a distinctive pungency and a subtly sweet note. Since Mazuma-shu takes 18–24 months to grow, it is used primarily in upscale cuisine and is among the more expensive variants.

実生種 (Mishō-shu)

Mishō-shu has greenish stems and a characteristic rhizome. With a fresh and juicy flavor that is clearly sharp, this variety is ready for harvest in only about one year. Due to its properties, it is frequently used for soba, sushi, and other fine dishes.

だるま系統 (Daruma-keitō)

Also known as the "Green Stem Variety," Daruma-keitō impresses with its upright growth and green stems. With a milder, elegant pungency and a cultivation period of 12–18 months, it offers an interesting alternative for chefs who rely on shorter growing times.

島根3号 (Shimane 3-gō)

This variety is a hybrid of Daruma and a regional variety from Shimane. Shimane 3-gō is robust against diseases and pests and is particularly suitable for the special mountain stream cultivation (渓流式栽培, keiryū-shiki saibai).

Western Wasabi (Seiyō-wasabi)

This refers to horseradish, which is native to Eastern Europe and is cultivated in Japan, particularly in Hokkaido. It has an elongated root and tastes more reminiscent of radish or cabbage than true wasabi. This variant is often used as an affordable substitute in industrially produced products and supermarket offerings.

Flavor and Preparation

Freshly grated wasabi unites an intense pungency with a natural sweetness and a subtly earthy note – the fresher the wasabi, the more aroma it releases. In Japan, in many restaurants when you order sashimi or soba, usually a whole wasabi root along with a grater (Oroshiki (jap. 卸金 or おろし器, "grating device") – often made of sharkskin) is brought to the table. This way, you can immediately experience the freshness and be sure that your dish is seasoned with genuine wasabi. Since the aromas are intense, it is advisable to use the freshly grated wasabi within approximately five minutes, as it rapidly loses its pungency.

Dishes with Wasabi

Production, Freshness and Imitation Products

The production of true wasabi is an artful craftsmanship. Its cultivation requires ideal, natural conditions – cool mountain streams with plenty of clean, flowing spring water, shady spots, and stony soils are essential. These demanding conditions mean that genuine wasabi can cost up to 250 US dollars per kilogram, making it about 25 times more expensive than fresh horseradish.

Unfortunately, fresh wasabi is virtually unavailable in Germany and Europe, as it is highly perishable and loses its aroma quickly. The wasabi pastes commonly found in Europe usually contain only 2–5% – sometimes even up to 25% – genuine wasabi. The majority of the paste consists of horseradish, mustard, as well as coloring and flavoring agents. These imitations can hardly come close to the Japanese original.

Culinary Uses

In traditional Japanese cuisine, wasabi is an indispensable companion to sashimi, soba, and numerous other dishes. The presentation of a whole fresh wasabi root with its accompanying grater is emblematic of authenticity and quality. In my own journey, particularly during my time in Düsseldorf, I noticed that genuine wasabi is almost always served in this authentic form in Japanese restaurants – while in European markets, almost exclusively heavily diluted pastes are offered.

Prices and Availability

In Japan, genuine wasabi is available in the form of rhizomes, which typically weigh between 50 and 120 grams and cost between 1,000 and 7,000 Yen, depending on quality (approximately 6–50 USD). Outside Japan, due to import costs and limited cultivation areas, prices rise significantly. The availability of fresh wasabi products is particularly limited in Europe, which often leads to the frequent use of lower-quality imitations.

Nutrients: Vitamins, Minerals and Calories

In addition to its unique flavor, wasabi also offers a considerable nutrient content. Per 100 g, it provides, for example:

• Vitamin C:  41,900 µg – important for bone structure as well as calcium and phosphorus balance.
• Vitamin B6:  274 µg – supports fat metabolism and the formation of neurotransmitters.
• Minerals:  Calcium, potassium, magnesium, sodium, and phosphorus contribute to a balanced nutrient profile.
• Calories:  123 kcal – makes wasabi a low-energy yet intense ingredient.

You can find further details about the nutrient values, for example, at geo.de .

Therapeutic Applications

The mustard oils contained in wasabi – specifically the isothiocyanates – are valued in phytotherapy. They act as locally effective rubefacients and possess antibacterial properties by inhibiting the growth of pathogens such as Bacillus subtilis, Escherichia coli, and Staphylococcus aureus. Together with other mustard oil-containing plants, such as nasturtium, these active ingredients are also used for the prophylaxis of respiratory and urinary tract infections.

Wasabi Fields in Japan and Edible Wasabi Leaves

On my travels in Japan, I had the opportunity to visit wasabi fields – an experience that vividly illustrates the demanding nature of this product. Wasabi grows almost exclusively in mountainous regions, where it benefits from cool, flowing spring water. In addition to the root, the wasabi leaves are also edible; they can be pickled or enjoyed dried. An interesting aspect is that products without preservatives must be consumed within a week once opened to fully retain their freshness.

Great Video from "Business Insider"

For an additional insight into the fascinating world of wasabi, I recommend an informative video from Business Insider. It not only shows the complex cultivation and harvesting processes but also highlights the versatile use of this natural product.

Conclusion

Wasabi is much more than just a spicy condiment for sushi. The demanding cultivation, the variety of types, the intense flavors, and its health-promoting properties make it an exceptional natural product. True authenticity is shown in the fresh presentation in Japan – from the whole root to the specially designed grater – while in Europe, diluted imitations often dominate the market. With this overview, we hope to give you a comprehensive, factual insight into the world of wasabi that encompasses both the botanical as well as the cultural and culinary aspects. Enjoy your meal!