Alphaclar S is a single –use cross linked polyvinylpyrroidone (PVPP). It is a colloidal haze stabilizer which can increase the shelf life of beer. Alphaclar S absorbs the haze-active polyphenols which would otherwise react with haze-active proteins in filtered beer to form colloidal haze during storage.
Beer contains polyphenols which are derived from hops and malt. The smallest (haze active) polyphenol molecules and the smallest (haze active) protein molecules will pass throughthe filter.
At first the beer may be bright but gradually the polyphenols with polymerize due to oxidation. Once they reach a certain size they can react with the haze-active proteins to form colloidal haze which is measurable and visible. Eventually the colloids can become large enough for them to sediment. Alphaclar S absorbs the polyphenols via hydrogen bonding. As PVPP is insoluble, beer filtration will remove the haze-active polyphenols which have been absorbed onto the PVPP. This takes away one side of the equation in colloidal haze formation, thereby improving the stability of beer.