Monitoring of beer filtration using photon correlation spectroscopy (PCS)

Abstract

In this work, different aspects of particles size distribution in filtered beer were investigated. The utilisation of commercial cellulase or protease formulations influenced significantly the stability of filtered beer. By using Photon Correlation Spectros-copy (PCS) untreated beer samples at 6 and 20°C showed good "chill" stability, while the samples treated with exogenous enzymes showed a significant modification in the particles size distribution and reduced colloidal stability. The particles size distribution in the filtrate appeared to be related to the decrease of the cut-off size of the membrane and of the flux from the membrane. As reported, the largest particle size diameter flowing through the membrane decreased in each type of sample over the course of the filtration, due to the fouling of the filtering media. The results allowed confirmation that at the beginning of the filtration trials the main fouling cause was the decrease of the pores size within the membrane structure, more than cake formation over the membrane surface, although this second effect prevailed after a certain time. © 2011 The Institute of Brewing & Distilling.