"Derived from the exoskeletons of shellfish and crustaceans including lobster and shrimp, Chitosan (kite-oh-san) is a polymer closely related to cellulose (wood fiber). The shells are powdered and repeatedly treated with heated alkaline solutions to destroy all proteins. Although people with shellfish allergies may be alarmed at the source of Chitosan, it will not, and cannot cause allergic reactions in humans. Allergic reactions are caused by specific protein chains. Chitosan is protein free and approved for dietary use and use as a water treatment product without shellfish warnings. Chitosan is positively charged therefore attracting negatively charged yeast cells much like a magnet. Together they are heavy enough to quickly fall out of suspension. Chitosan has a reputation for being fairly gentle on the character of finished wine."