Pure wasabi powder is a simple way for sushi lovers to experience true wasabi without hunting down the elusive, fresh rhizome. Most wasabi powders and pastes are actually mixtures of ground mustard seed, horseradish and green coloring. The delicately floral, and nutty flavor of real wasabi is easily destroyed by heat, so use this pure wasabi powder in cold dishes and sauces. Wasabi pairs particularly well with fish, avocado, ginger, and soy sauce.To fully release its flavor, it should be added to a liquid and left for about 10 minutes. Wasabi powder is best stored in the refrigerator or freezer if it will not be used for some time.