Interactions between macromolecules and membranes: their effects on beer quality

When filtering beer at pore sizes of 0.45 μm and below, some desirable components may be lost, even though they are orders of magnitude smaller than the pores. In this work, a model beer solution of pure components has been filtered through 0.2 μm membranes to investigate this problem. Starch (a model for the long chain carbohydrates) at a concentration of 1500 mg.l-1 and casein (a model for the protein fraction) at a concentration of 150 mg.l-1 were found to result in reduced permeate fluxes in the region of 20–40 l.m-2.h-1. [Continues.]