PBW stands for Powdered Brewery Wash. This product is widely used in commercial breweries across the country. Use 1 - 2 ounces per gallon for cleaning boil kettles, or an ounce per gallon for fermenters, kegs and other brewing equipment. Soaking overnight will easily remove stubborn, caked on organic deposits without scrubbing. PBW is environmentally friendly, biodegradeable, and will not harm septic systems.