Development of Colloidal Stability During Beer filtration

Fritz Briem and E. Geiger. Poster presented at the MBAA 111th Anniversary Convention, Minneapolis, Minnesota, September, 1998.

Abstract
The results of various stabilization trials, which have pilot scale as well as practical character, are presented and it is demonstrated that during traditional beer filtration with kieselguhr, the colloidal stability of the beer decreases parallel to the filtration time. Beer stability is measured by the "Forciertest" described in Mebak or slightly modified methods. An immunochernical method for the detection of haze positive protein and polyphenol-protein complexes is described. It was shown that the reduction of relevant fractions of proteins cannot influence the deterioration of beer stability. Only the reduction of polyphenols by PVPP is effective against this phenomenon. The standard analytical methods normally used in the brewery such as protein fractionation with MgS04 or (NH₄)₂SO₄ show no correlation with the decrease of beer stability during kieselguhr filtration. The effect of different methods of beer stabilization in different breweries and in various beer types is discussed and it is shown that beer stabilization cannot be transferred from brewery to brewery with the expectation of comparable results.
Keywords: colloidal stability, polyphenols, anthocyanogens, tannins  

Sintesis
Este poster ensefia los resultados de varios ensayos de estabilizacion, los cuales tienen el caracter de tanto de escala piloto como practicos. Demuestra que durante la filtracion tradicional con tierra diatomita la estabilidad coloidal de la cerveza decrece paralelamente al tiempo de filtracion. La estabilidad de la cerveza es medida por el "Forciertest" descritc, por Mebak o metodos levemente modificados. Adicionalmente se describe un metodo imonuquimico para la deteccion de proteina turbio positiva y complejos polifenoles de proteina. Se demonstrara que la reduccion de fracciones relevantes de protemas no pueden influenciar el deteriorc, de la estabilidad de la cerveza. Unicamente la reduccion de polifenoles por medio de PVPP funciona contra este fenomeno. Especialmente los metodos analiticos estandard normalmente usados en la cerveceria como fraccionamiento de proteina con MgS04 o (NH4)2SO4 no dernuestran ninguna correlacion con la reduccion de estabilidad de la cerveza durante la filtracion con kieseiguhr. El efecto de distintos metodos de estabilizacion de cerveza en cervecerias distintas y en varios tipos de cerveza sera discutido. Estos demostraran que la estabilizacion de cerveza no pueden ser transferidos de cerveceria a cerveceria con la expectativa de obtener resultados comparables.