‘Wasabi’ refers to both the plant and the popular food condiment. It is a mainstay compliment for Japanese dishes like sushi, sashimi and soba. Wasabi paste is often served as a manufactured paste packaged in tube form. The fresh made paste, grated directly from the plant’s root stem can have a shorter shelf life. However without any preservatives or other additives, it is prized as the superior or even only way to serve Wasabi. Fresh grated Wasabi boasts a very noticeable milder, more natural tasting flavour profile and distinct floral aromatics. It is applied by itself to fish, meat and vegetable dishes or mixed with soy sauce for sushi and sashimi.
Wasabi has that nose clearing 'heat' like mustard and horseradish – as opposed to ‘chilli or pepper heat’. Indeed it is similar to Horseradish and so outside Japan the words are often interchanged. In fact most cheap ‘wasabi pastes’ are mainly processed horseradish mixed with green food dye. Wasabi is now widely used in dried snacks, sweets, drinks and a myriad of other products. Fresh Wasabi has a great taste and lots of medicinal qualities.
Wasabi japonica is a member of the Brassica family which includes horseradish, most leafy greens, mustards and canola. Commonly called the Mustard Family it is a major agricultural group in most countries. Wasabi needs the right conditions to grow well and the aim is to replicate its natural environment. It prefers a temperature range of 5C to 22C and lots of shade. In Australia this is best created in a fernery where the large leaves don't get too much sun and can be kept moist and cool in the warmer months - like the ferns. Best grown in large pots with a pH neutral mix that is rich in organics and well draining. Although the plants must be kept moist they do not like being water logged.
All parts of the plant are edible but the best bit is the long carrot like stem that grows down into the pot. The plant is quick growing in the cooler months but takes around 20 to 24 months to get the best flavour. At this stage the stem should be 15 to 20cm long and is best harvested in spring and autumn. During this time the leaves and flowers are excellent in salads. Break off any suckers to focus growth on the mains stem.
Wasabi is best eaten fresh and stored in the refrigerator (never the freezer) where it will keep for about 4-6 weeks. Only cut off what you are going to use as the flavour fades quickly. Grate into a paste using a specific Wasabi grater or Ginger grater. This is best done at the table to get the perfect flavour.