Star San is an odorless, colorless acid-based surface sanitizer that is used heavily in the brewing industry. It works by lowering surface pH to a point that eliminates potential contaminants. While it is effective, it is also safe to use. Star San is used at a rate of 1 ounce per 5 gallons of water. Clean equipment can be sanitized with a 2 minute contact time in a solution made at this rate, and no rinse is needed. Star San does foam up, but don't fear the foam! Foam from Star San helps to sanitize in cracks, crevices and other hard-to-reach places. Residual foam left in fermenters and other equipment is safe, non-toxic and will not affect beer or wine. See for yourself why Star San is the preferred sanitizer of professional and home brewers alike!