I've tried this brand (Hime) several times, and it always came up a little "short" on flavor.  The last time I tried it, I purchased it from Kroger's Food Store (sorry, Amazon).  I ended up taking it back and getting my money back.  I've tried S&B powder "Wasabi" powder, and it convinced me to start purchasing that brand.  Especially when a 1 Kilo bag of powder is less than $15 bucks!  It's the best imitation Wasabi powder I've ever had.  To make it last (I probably have several years supply of it), I vacuum-packed 1/4 pound bags in the Food Savor bags, and then stuck them in my freezer.  The bags are "double-sealed", as there is a vacuum bag inside of another vacuum sealed bag.  Double protection, I hope.