True Wasabi: What Is That Green Paste Really?

By Rowan Jacobsen

THE FAMILIAR BLOB OF green “wasabi” served at nearly every sushi bar in the world is not really wasabi. It’s horseradish, ground and mixed with green food coloring and sometimes a touch of Chinese mustard. True wasabi (Wasabia japonica), a semiaquatic herb native to Japanese mountain streams, is rare and pricey, and doesn’t keep nearly as well as horser…