Wasabi Zuke – A traditional Japanese pickled dish!

Wasabi known as Wasabia japonica is famous for its swollen stem called a rhizome and is very central to Japanese cuisine. Wasabi is a relative of the Brassicaceae family which includes cabbages and horseradish. Wasabi was first grown in Japan and has been cultivated for over the millennium.

Wasabi ‘King of the Herbs’ is tough to grow and requires a moist, shady environment. It grows naturally in mountain streambeds in Japan. The cultivated wasabi is called ‘Sawa’ when grown in semiaquatic conditions compared to ‘Oka’ when grown in the fields. Today, Wasabi is grown in Northern Ireland by Wasabi Crop Wasabi Crop.

Real fresh wasabi is expensive. The cheaper version is dispensed from a tube to give a green paste that is used to complement sushi dishes in restaurants. True wasabi is grated in front of the customer using a traditional Japanese Sharkskin board or something similar. Wasabi is so rare that even in Japan fake wasabi is used. This imitation wasabi is a mixture of horseradish, Chinese mustard and green food colouring.

Real wasabi paste looks and tastes quite different from the fake stuff. Rather than a uniform green, it is a mix of coarse light-green and white particles and has a flavour that is more than just zingy heat.

Wasabi has associated medicinal properties which are antibiotic in nature and are capable of inhibiting microbial growth and suppressing oral bacteria.  In some research articles, wasabi was found to have anti-cancer properties in addition to anti-inflammatory activity.

Why not buy some wasabi leaves and stems to make delicious Wasabi-Zuke!

Wasabi zuke is a popular pickled dish served in Japan and can be prepared by taking all parts of the wasabi plant. This chopping and mixing of all the leaves, flowers, leafstalks and the ground roots with salt water and sake including sugar.  Wasabi Zuke can be a great dinner dish or even a suitable side dish especially with drinks. These types of dishes are called kasuzuke (food pickled in the lees from sake brewing). Wasabi Zuke was developed by merchants in Fuchu which is modern-day Shizuoka which flourished in the Edo Period.

Today, Wasabi Zuke is modified to contain added spices, fragrance, and wasabi flavouring to boost its flavour. The related dishes are ‘wasabi-nori’, ‘wasabi-miso’ and ‘kazunoko’ (herring roe).  Wasabi zuke means ‘pickled wasabi’ and it is a product of the Shizuoka Prefecture.  Shizuoka City is the reported birthplace of wasabi in Japan.

Wasabi Zuke is avaiable in Shizuoka but unfortunately, it is a rare and expensive delicacy away from this region – even in Japan!  The Wasabi is grown on the mountain slopes along the Abe River in Shizuoka City.  The central ingredients for Wasabi Zuke are the sake kasu/sake white lees which all came from the sake brewery in Shizuoka Prefecture.  The other ingredients salt, brown cane sugar and the mirin/sweet sake are all made in Japan! – a truly Japanese favourite.

In Japanese cuisine both the rhizome and the leaves of the wasabi plant can be used to create fantastic dishes.  The rhizome can be grated over foods for added spice. Fresh wasabi leaves can consumed, either fresh, pickled or to create Wasabi-Zuke. The ‘zingy heat’ of wasabi is not released until it is macerated in your mouth.  Consequently, the flavour depends on how finely it is grated and how long it is exposed to air.  Remember wasabi releases the volatile compound allyl isothiocyanate – the Wasabi Kick and flavour and heat dissipate in about 20 minutes.  It is best to grate the wasabi rhizome just before you consume it, and use an oroshi grater or something similar.

Only true fresh wasabi can be found at specialty grocers and high-end restaurants.  This product is usually sold as a rhizome (sometime referred to as a root) or as a jarred paste.  In addition,wasabi can be ready to use as a dried powder.

You can add real fresh wasabi to roasted legumes for extra spice or grate over fish and rice dishes.  The more adventurous could spread fresh wasabi on your favourite sandwiches and if lucky served with your mashed potatoes at your favourite restaurant and politely finish off with a spice up Bloody Mary with wasabi leaves and stems.

Wasabi Leaves and stems are available from Wasabi Crop – all grown freshly in County Armagh, Northern Ireland.

Wasabi Crop

Sofia Kitson

The Wasabi Kick

The freshly grated wasabi hides a secret known as the Wasabi Kick which produces a zingy heat when consumed with your favourite food. This pale green grated powder is known as Japanese horseradish, but this is not the same as the horseradish which complements your roast dinner. It is a distant cousin and is formally known as Wasabia japonica – a member of the Brassicaceae family. Wasabi is closely related to cabbage, cauliflower, broccoli and mustard.

Wasabi is cultivated in Japan alongside mountain stream beds enabling the production of a vast carpet of unique plants. They are long-stemmed with heart-shaped leaves and white flowers which branch from a knotted, thick, swollen stem, known as a rhizome.

The two main methods of growing wasabi involve the usage of semi-aquatic conditions to produce the sawa type (grown in water) and in fields to give oka wasabi (grown in soil). Usually, under sawa conditions larger rhizomes are formed than in oka grown wasabi. However, both give that extraordinary wasabi kick.

The wasabi plant is tough to cultivate and it flourishes best in mountain stream water.  At Wasabi Crop, we have developed expertise through continuous chemistry to generate wasabi rhizomes, leaves and stems for all our customers.

Real wasabi is expensive to cultivate and the majority is consumed in Japan: this is the major reason why most people have not tasted real wasabi. Most wasabi sold in supermarkets, sushi bars and restaurants is fake.  This fake wasabi usually consists of horseradish, mustard, starch and green food colouring.

Can you tell the difference between true wasabi and fake wasabi?

Yes, you can!

In most cases, when wasabi is ordered with your food, a squirt of ‘bright’ green toothpaste-like material is placed on your plate – and the customer is under an illusion because it is almost certainly fake wasabi!

Fake Wasabi

Fake Wasabi

Genuine wasabi is grated in front of the customer to produce the wasabi powder.  The best grater to use is the sharkskin paddle because it can finely grate the rhizomes. This grating process initiates chemical reactions through the mechanical damage of the cells inside the rhizome producing volatile compounds, rich in flavour.

Real Wasabi

Real Wasabi

The heat usually produced lasts for about 20 minutes and this is usually enough time to experience the wasabi kick.  This event does not happen with horseradish – which can retain its potency and sharp flavour for many days. The chemistry of horseradish and wasabi are similar but each have different amounts of naturally flavoured compounds to each their individual, unique flavour profile.  The central component in horseradish and wasabi rhizomes are glucose sulphur-containing organic compounds known as thio-glucosides.

During the grating and maceration of the rhizome, the cell walls break releasing the thio-glucosides and the enzyme called myrosinase.

What is the role of myrosinase?

Essentially, the main function of myrosinase is to break down the thioglucosides into glucose and by a chemical rearrangement called the Lossen Rearrangement generating varying amounts of isothiocyanate compounds.

So, during this process, the horseradish and wasabi will both produce different concentrations of the isothiocyanates.  Interestingly, horseradish generates about 10% less of the total isothiocyanates per kilogram of horseradish compared to wasabi.

The major isothiocyanate compound present in wasabi is called allyl isothiocyanate and this association is REAL WASABI producing a pungent zingy wasabi kick.  Another component is called 2-phenylethyl isothiocyanate and this is surprisingly found in horseradish. Other compounds include 6-methylthiohexyl isothiocyanate, 7-methylthioheptyl isothiocyanate and 8-methylthiooctyl isothiocyanate.

Studies have shown that isothiocyanates inhibit microbe growth and provide great benefits for preserving food against spoilage and suppressing oral bacterial growth.

More on allyl isothiocyanate!

The allyl isothiocyanate is responsible for the wasabi kick generating heat when consumed and this is different from that produced by chillies and peppers.

wasabi kick

wasabi kick chemistry

Hot peppers contain the compound capsaicin which stimulates the tongue. The heat created on the tongue can only be removed with oil based foods.  The experience that you will obtain from wasabi in your mouth is that of allyl isothiocyanate volatile vapours stimulating the nasal passages and this simply does not take place with capsaicin-containing foods.

In summary, the wasabi experience is related to the amount of allyl thiocyanate consumed. So, eat and enjoy plenty of freshly grated wasabi. The only solution if you can not manage the wasabi kick is just to control it with the consumption of food and/or beverages.

Real wasabi is expensive and the majority of it is consumed in Japan – here at Wasabi Crop we will give you the opportunity to buy wasabi varieties and let’s not forget the delicious leaves and stems for your stir fries and salads.

Enjoy your fresh wasabi – providing new foods for your table!

Sofia Kitson

Wasabi Crop Blog

Grating Fresh Wasabi Rhizomes


The secret of enjoying fresh wasabi lies in the grating of the rhizome to release the pungent zingy flavour. Fresh wasabi rhizomes are a rare and precious culinary commodity prized by sushi dining chefs. The best grater to use is the traditional Japanese ‘Samegawa-Oroshi’-Sharkskin Grater but these are quite expensive to purchase. However, you don’t have to worry as you can always use any fine grater available.

So, to begin the grating process you first wash the rhizome in cold running water and lightly trim off only the black bumps on the surface. This blackness is a result of a natural process due to air oxidation taking place at the surface of the rhizome.  Carefully, peel off the outer thin black layer on the rhizome, (if any) you find by using a potato peeler or something similar. Then begin grating from the thicker side a this section is fresher and yields a more zingy taste to give that beautiful pale green coloured wasabi paste.The freshly grated wasabi paste should not be stored in a metallic container, it is best to use an unsealed ceramic basin. During the grating process, a pinch of sugar can be placed on the grater to give the wasabi a milder flavour.
The remaining rhizome can be preserved for at least one month in a refrigerator by wrapping it up in a damp towel. Remember to replace the cloth every 2-3 days to keep the rhizome in good condition. If wanted, the whole rhizome can be grated all at once to produce small parcels of wasabi paste wrapped in ‘cling film’ and stored in the freezer until required.
Wasabi Japan

Freshly grated wasabi on a traditional Japanese Sharkshin

It is better to start grating the rhizome from its top end by swirling around the whole root to produce the best aroma and pungency as each part of the rhizome has slightly a different flavour profile and associated pungency. This approach will maximise the blend of the whole root. Once grated, the wasabi must be kept chilled in a refrigerator to preserve its pungency which dissipates within two hours or at room temperature the pungency will completely disappear in the space of 15 minutes. 

The wasabi rhizome should be maintained in a chilled state and not frozen otherwise its fibre will be damaged. If wishing to keep the grated wasabi paste for longer than one week, then the colour will darken and its pungency and smell will change due to the air oxidation of allyl isothiocyanate. It is better to grate the rhizome as and when required to eat immediately.

So, please visit Wasabi Crop and sign-up for the latest Wasabi Crop updates.

Enjoy your fresh wasabi – providing new foods for your table!

Sofia Kitson

Wasabi Crop

Growing Wasabi in Northern Ireland

mazuma wasabi

Here at Wasabi Crop we have been growing Wasabi for the last several months and will be ready for harvest in 2018. To many this may seem a long time, but it does take two years to grow top quality rhizomes. The good news is that leaves and stems will be for sale in 2017. Wasabi Crop is the only commercial grower in Northern Ireland and we cannot wait to serve all our customers with our Wasabi varieties. These include Mazuma, Daruma and Green Thumb including all their corresponding leaves and stems.


Mazuma Wasabi Plant from our Wasabi Crop Facility

The history of wasabi goes back to the ancient Japanese who were consuming wasabi around 14,000 B.C.  The cultivation of wasabi is mostly done in Japan and gained popularity through the serving of sushi. Wasabi complements sushi through its flavour and associated antibacterial properties to offset food poisoning. Wasabi has an interesting botany. It is known as Wasabia japonica which is part of the Brassica family. This family consists of horseradish mustard and cabbage.


Fresh Baby Wasabi Leaves & Stems Grown at Wasabi Crop

Wasabi has very distinctive heart-shaped green leaves which can grow on long thick stems protruding from the crown of the plant.  The wasabi stem is known as the rhizome and is located at the base of the plant and over time grows upwards above ground. The rhizome is ready for harvest within two years. The rhizome is the most valuable part of the plant and this is used to produce freshly grated wasabi paste. The harvested pale green rhizome can be grated using a sharkskin grater.


Large Wasabi Leaves from our plants

Wasabi is especially challenging and expensive to cultivate and this is the reason why there is a lot of fake wasabi being sold and consumed. These wasabi so called products contain tiny amounts of real wasabi such as less than 0.3%. It is amazing that they can sell these as wasabi products. Interestingly, just by reading the ingredients, on these so called wasabi foodstuffs, you will be amazed they contain a combination of horseradish, mustard and green dye and very tiny amount of real wasabi. Unbelievably, they are all marketed as wasabi products which do contain any wasabi at all – scandalous!

So, at Wasabi Crop we have set ourselves the challenge to grow real fresh wasabi – here in County Armagh, Northern Ireland. County Armagh is famous for growing apples such as Bramley


Bramley Apple Trees – County Armagh

After much research into cultivating wasabi we have mastered the growing. Presently, we are growing Mazuma wasabi. All our wasabi will be ready for 2018; this may seem far away because wasabi rhizomes take two years to mature. Just think our customers will be able to buy real fresh wasabi from us in 2018 and every year after that.


Freshly Grated Wasabi

On receiving the wasabi rhizome – recognised by its stunning pale green colour – just grate it in circular motions by using a grater it is best to use a traditional Japanese sharkskin grater. Then just add the freshly grated wasabi to your favourite recipe of choice. Imagine the possibility of wasabi ice cream and wasabi chocolate or even a wasabi beverage. The experience of tasting freshly grated wasabi with its pungent heat generates a taste which is very different from chilli for example.

The wasabi kick comes into action and develops quickly to diffuse up the sinuses rather than staying in the mouth, then quickly dissipates. The wasabi kick experience delivers a refreshing heat, – so try it. Not only is wasabi a herb it is a medicinal plant providing heath benefits due to its key component of allyl isothiocyanate which releases during the grating process. The isothiocyanates enable wasabi to produce associated antibacterial, antimicrobial and antiparasitic properties.

Several research studies are evaluating the constituents for the prevention of certain disease states like cancer. Wasabi would make a great contribution towards a healthy diet by providing low cholesterol and sodium constituents. Consequently, it is a source of dietary fibre and vitamin C and a provider of vitamin B6. In addition to the elements of calcium, magnesium, potassium and manganese.

So, please visit Wasabi Crop and sign-up for the latest wasabi crop updates.Enjoy your fresh
wasabi – providing new foods for your table!


Sofia Kitson

Wasabi Crop

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