Bentonite is an absorbant clay. It can also absorb large amounts of protein molecules from aqueous solutions. That fact makes it useful to winemaking, where it used to remove excessive proteins from white wine, helping to prevent to formation of a cloudy haze. Finally, it will induce fairly rapid clarification of both white and red wines.
Usage: 3-4 teaspoons per 5 gallons. Mix with hot water before adding.