Wasabi is a pungent root similar in taste to ginger and hot mustard. It is sold fresh, as a prepared paste, or in dried powdered from. Fresh wasabi root should be peeled and grated from the stem top down and should be used within 1-2 days of cutting before it loses its freshness and pungency. The powdered variety may be cheaper, but it actually powdered horseradish colored green with mustard added. Wasabi paste can be made from the powder or the root. Real wasabi is more expensive but has a more potent flavor.