DEEP  DIVE  INTO  WASABI

Traditional wasabi cultivation is a meticulous and time-intensive process that has been practiced in Japan for centuries. Wasabi (Eutrema japonicum) thrives in cool, shaded environments with pristine water flowing over its roots. The most prized wasabi is grown in mountain stream beds using the sawa (water-grown) method, where plants are carefully nestled in gravel, sometimes over a base of rocks, with a controlled flow of fresh, oxygenated water. This method, found in regions like Shizuoka, Nagano, and Iwate, produces the highest-quality wasabi with a smooth, complex heat and rich aroma. Growing wasabi this way takes patience—plants require 18 to 24 months to mature, and any disruption to water quality, fluctuations in water and air temperatures, too much or not enough shade etc can significantly impact growth. The down-side of this growing method is that, while wasabi is a good scavenger of nutrients from water, if natural nutrient availability does not support increased growth, at favourable times of the year, quality and flavour will reduce, without nutrient amendments being made. Because of these demanding conditions and the implications of climate change, not to mention the back-breaking work required, real wasabi remains one of the rarest and most labour-intensive crops in the world.

In non-traditional commercial wasabi cultivation, techniques have been developed to overcome the challenges of growing wasabi outside its natural habitat, which despite being ideal for the plant, is highly prone to storms and flooding. These methods include growing in soil, the primary cultivation method employed in China for blended wasabi powder production. Research out of NZ has reported that soil-grown rhizomes tend to lag behind water grown, in terms of glucosinolate content, until rhizomes have reached the 100g size that is. As soil grown wasabi tends to result in a high proportion of leaf stalk, and multiple small rhizomes, this suggests that growing wasabi in the field, under cover, would indeed result in an inferior product if harvested too early, i.e. before the 100g rhizome size has been achieved. Another method, common to North America, is cultivating wasabi in gravel beds within polyhouses. Instead of relying on natural mountain streams, these greenhouse operations spray fine nutrient mist directly over plants, supplying essential minerals and dissolved oxygen while helping to regulate temperatures during the summer months. This approach however, often leads to excessively high humidity, promoting stem (rhizome) and leaf rots. Wasabi is highly susceptible to fungal infections, which can sometimes result in total crop loss. In greenhouse systems where misting is used only to help reduce air temperature, rather than both reducing temperature and providing nutrients, plant growth can slow dramatically during the warmer six months of the year, even with supplementary nutrition provided. While these methods offer scalability and adaptability, maintaining proper shade, airflow, water chemistry, as well as good temperature control, is critical. Wasabi demands optimal conditions to produce the highest-quality, disease-free rhizomes.

Our wasabi is cultivated using pure rainwater and a minimal level of our in-house, carefully balanced blend of simple, high-purity plant nutrients. Keep in mind that as rainwater is a rare commodity in arid inland Australia, wasabi can't be grown in the traditional way as in locations where rainfall exceeds 3,000 mm per year. So with less nutrient containing water supplied to plants, nutrient content needs to be increased accordingly. But not excessively as this will lead to build-up in the root zone, especially when run-off is minimised, followed by plant stress and consequently reduced growth and rhizome quality. We grow in 100% organic substrate with optimized root zone oxygenation, ensuring healthy, vigorous plants. Our insulated growth chambers maintain stable temperatures of around 15°C year-round, utilizing passive water reservoirs, to help stabilise air temperature, refrigerated air handling units and chillers for summer cooling—while outside temperatures exceed 40°C, our wasabi is fully optimised at 16°C. Powered by solar energy for sustainability, our system integrates ultra-efficient full-spectrum LED lighting, providing 11 hours of daily light to support strong leaf and rhizome development. Wasabi farmers often talk about the crop needing up to 85% shade (in mid summer) but what most people fail to understand is that natural sunlight also supplies an equal amount of invisible infra red. It's this IR that wasabi plants do not like. LED light on the other hand has no significant IR content, so plants are able to benefit from higher light levels without becoming stressed. We meticulously regulate temperature, air circulation, and humidity, to create ideal pest and disease-free growing conditions. By starting with disease-free tissue cultured plant material, and carefully selecting superior cultivars like Mazuma, Mikado, and Green Thumb, we focus on optimising rhizome development through strategic offset management. Our precision-driven approach ensures consistent, premium-quality wasabi, grown with sustainability and excellence in mind.

Wasabi is prized not just for its fiery heat but also for its complex flavour and health benefits. It contains unique glucosinolates that convert into isothiocyanates (ITCs), giving it pungency. While it may not always be as hot as some imitation wasabi pastes, it offers a greater depth of flavour, along with antimicrobial, anti-inflammatory, and potential anti-cancer properties. Different parts of the wasabi plant vary in intensity—freshly grated rhizome develops a balanced, aromatic heat that peaks after 5 minutes but then fades after 15 minutes or so. Having around a quarter the glucosinolate content compared to rhizomes, the petioles (leaf stalks) and leaves have a milder, slightly sweet heat, making them ideal for fresh salads or pickling, while wasabi flowers provide a delicate spiciness with floral notes. Commercial wasabi products also differ in potency—freshly grated rhizome delivers the purest experience, while upon re-hydration, 100% rhizome powder can retain much of its original heat and complexity. However, many wasabi pastes and powders are, or do contain, horseradish, mustard, and artificial colour, and often lack the depth and nuanced heat of real wasabi. If you ask a wasabi powder supplier from China for a lab-signed Certificate of Analysis (COA), it's unlikely one will be available without a prior commitment to buy a tonne of product. If you do manage to be sent one, be aware there is no way to verify the analysis on a 'transcribed COA' that does not list testing lab details ...be aware of scammers. Whether enjoyed fresh or in carefully processed forms, authentic wasabi provides a unique sensory experience that goes beyond just heat, offering layers of flavour and notable health benefits.

​

While traditionally, Mazuma is considered a superior cultivar, more recently, selections such as Green Thumb and Mikado are proving to have better distribution of glucosinolates throughout the entire plant, with their powdered leaf products showing significantly higher levels of spiciness when added to smoothies etc. This has been confirmed by an Australian study, which reported finding significant levels of 6-MSITC in all plant parts of the cultivar GT, while an earlier study from Japan on unspecified cultivars, failed to find this particular ITC in leaves and petioles of Wasabi.