Recovery of beer from surplus yeast by membrane filtration.
Cross flow membrane filtration trials have shown that a substantial amount of beer can be recovered from surplus yeast and tank bottoms by concentrating the yeast up to 23% dry matter. Blending the permeate back into wort in brewhouse or at fermentation stage does not impair the flavour in concentrations of 10 to 20%. Commercially available membrane filters have been evaluated on pilot-scale, in plate and frame, tubular and spiral wound configurations. Best results have been achieved with a continuously operated plate and frame filter configuration using 0.5 to 1.0 micro m membranes. Microfilters are preferable to ultrafilters. Results of a satisfactory production scale trial are given.
Keywords : beer cross flow filtration membrane porosity recovery wort yeast