If you're familiar with sushi, chances are you've seen or tried the green paste that is usually served on the plate next to sushi rolls or sashimi pieces, beside the soy sauce. Wasabi is a common condiment in Japanese cuisine, and it's not only used when serving sushi. Also known as Japanese horseradish, this root vegetable has a pungent flavor and packs a punch when eaten, although the burn you feel is short-lived and experienced in the back of the nose and not in the mouth like spicy food.
What Is Wasabi?
Wasabi is a root vegetable, green in color, from the same family as broccoli, cabbage, cauliflower, and mustard. It needs to be grated for consumption and its flavor fades away rapidly. Of a bright green color inside, wasabi is hard to grow, requires a steady supply of water, a particular type of soil, shade, and a temperature that needs to remain regular in order for the root to grow adequately. Thus, real wasabi is expensive. A pound of it might cost between $100 to $125, making it cost-prohibitive for your favorite Friday night sushi joint.
So wasabi as the average person might know it is not real wasabi. What you get with your rolls or sashimi is a mixture of horseradish colored with spirulina or spinach, oil, sweeteners, and maybe a minuscule portion of the real thing.
Spice or Vegetable?
True wasabi is made by peeling the root of the wasabi plant and then grating it using a special studded ceramic grater, which causes it to form a sort of paste. Technically, wasabi is a vegetable. But if you take the same root, dry it, and grind it up into a powder, it is then technically a spice. So the powder form, inexpensive and not true wasabi, is a cheap spice, whereas the real root, fresher, milder, and fragrant, is a vegetable. An expensive one.
A third form of wasabi comes in a tube and is made from real wasabi root, dried, ground, and reconstituted along with various stabilizers and other seasonings. While it isn't exactly cheap—around $10 per tube—it is a decent middle option between the powdered not-really-wasabi and the crazy-expensive real root.
What Does Wasabi Taste Like?
Assuming you've never tasted freshly grated wasabi root, and probably never will, there is no reason not to say that the paste that comes with your sushi order, the pungent and green horseradish, isn't wasabi. It is the wasabi that we know.
As such it has a pungent and deep flavor, very aromatic, very fresh, and sweet. It is also shortlived as a taste, and a little more vivid as a feeling in your nose. Good for clearing your nasal passages, the paste complements the flavors of strong and oily fishes, but also adds spice and a kick to each bite. Historically wasabi has been incorporated when eating raw fish because of its antibacterial properties, as they may safeguard the well-being of eaters when consuming uncooked seafood.
Because wasabi powder, even if not the real thing, is affordable enough and has a great taste, it is a nice spice to have around and experiment with. Japanese cuisine includes it in multiple recipes, and not just the ones involving raw fish. It can be easily added to mayo, hummus, guacamole, mashed potatoes, salad dressing, and deviled eggs.
Where to Buy
Real wasabi may be difficult to come by, due to its price and limited availability, and because not too many producers have it year-round. Online searches can bring you to farmers across the world, but local specialized growers are available both in the US and the UK. The powder form is easily found in supermarkets, Asian markets, and online retailers.
If lucky enough to have a piece of real wasabi root, you need to place it in a glass of water in the fridge, stems out of the water, and change the water daily. It might keep well for 10 to 14 days under proper care. However, the non-wasabi "wasabi" powder will keep in the pantry from 1 to 4 years, but follow the manufacturer's use-by dates.