Yeast cells, beer composition and mean pore diameter impacts on fouling and retention during cross-flow filtration of beer with ceramic membranes

Clarification of rough beer (RB) and pasteurisation of clarified beer (CB) by cross-flow microfiltration (CFMF) stand as potential applications of membranes in the food industry. This study is based on the comparison of the resistances to mass transfer obtained during the filtration of RB and CB. Empirical correlations made it possible to calculate the CB resistances for the same conditions of transmembrane pressure and cross-flow velocity as for the RB filtration runs. The 1.4 μm membrane led to much lower resistances than the other membranes because of the lower retention rates of the beer compounds such as proteins and polyphenols. In this case, the predominant fouling mechanism was due to the yeast cell layer which was very sensitive to cross-flow velocity. On the other hand, with the 0.1, 0.45 and 0.8 μm membranes, the retention or adsorption of the CB compounds, such as proteins and polyphenols was the predominant mechanism. The resistances obtained with the rough and CB were fairly similar. We assume that the presence of yeast cells lead to less compact proteins and polyphenols fouling.