To achieve colloidal stability it is necessary to remove either protein, polyphenol, or both from the beer. During filtration, the most commonly used stabilizers for removing proteins is amorphous silica gel (e.g., Lucite®). Polyvinylpolypyrrolidone or PVPP (e.g., Polycar AT®) is typically used for removing polyphenols (15). The stabilization procedures typically used are:
Silica Gels with Main Beer Filtration
A wide range of amorphous silicas are available.
PVPP with Main Beer Filtration
PVPP can be added in combination with kieselguhr in the slurry tank; but to achieve better control, it may be preferable to add the PVPP separately prior to kieselguhr filtration.
PVPP-Impregnated Sterilizing Sheets
PVPP can be incorporated into sterilizing filter sheets.
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