Investigation of plugging colloids on microporous membrane filters.

Meier, P.M., Jansen, G.P., Blazka, S. and Hegde, R.

Abstract
An investigation into the clogging of sterilizing beer filtration membranes and the possibilities for countering the problem is described. Used membranes from five breweries were examined using attenuated total reflectance (ATR) infrared spectroscopy and scanning electron microscopy (SEM). A comparison of the images thus obtained with those obtained after solutions containing substances corresponding to colloidal beer constituents (barley beta glucan, maize protein, gallotannin) had been filtered through new membranes of the same type facilitated the identification of the colloidal matter clogging the brewery membranes. Carbohydrates and proteins were found to predominate, with tannins also occasionally present. The most rapid clogging of the laboratory membranes resulted from filtering a solution containing beta glucan and protein. When this preparation was passed through two membranes in succession, both became clogged, indicating a loose but reformable colloidal association between the two substances, although the upstream membrane collected more protein and the downstream one more beta glucan. Examination of membranes from a similar pair of brewery filters showed the same pattern of results. A cleaning procedure using hot water, a detergent, an oxidizing agent, and beta glucanase was found to be an effective means of removing much of the colloidal matter from clogged membranes.
Keywords : beer beta cleaning filter glucan membrane protein sterile filtration