Wasabi is a plant in the same family as mustard and horseradish. It grows naturally along stream beds in mountain rivers in Japan, but can be farmed. The leaves and root of the plant are edible, and cause a pungent, nasal-clearing sensation in the nose. The taste is much sweeter and complex-tasting than the paste you usually get in sushi bars.
Fresh wasabi is expensive and is hard to come by in the US but has been causing a sensation lately. Upscale sushi joints have started using fresh wasabi in place of powdered wasabi. Some small farms in the Pacific Northwest and in the Blue Ridge Mountains have started farming wasabi, making it more sustainable, as we are no longer limited to flying it in from Japan. Supporters argue that since you only need a little and the root keeps well, the cost is justified.
To prepare fresh wasabi root, the outer skin carefully using a paring knife or vegetable peeler, removing the knobs where the branches were attached. Next, grate the root with a wasabi grater, which can be made of sharkskin or ceramic. Grate in a circular motion, and gather up the finely grated root and pile it in a mound and let the flavors sit for 15 to 20 minutes. Serve at room temperature. Store any unused pieces in damp paper towels in the refrigerator. Please note: wasabi is very hot, and should be treated like a fresh chile pepper when being handled. Don't touch your eyes or sensitive skin after handling it.
(Image: Kathryn Hill)