Clarification of rough non-alcoholic beer by ceramic membranes: analyses of fouling and beer quality

In the present study, the clarification of rough non-alcoholic beer (RNAB) was investigated in a crossflow pilot plant consisting of a tubular ceramic membrane with nominal pore diameter of 0.45 μm. According to the characterizing curve of log(d2t/dV2) versus log(dt/dV), the mechanism of fouling has been determined to be the blockage of membrane pores at the initial stage of filtration (complete blocking model) followed by the formation of a severe cake layer successively. The contributions of each, reversible and irreversible fouling were evaluated by comparison of hydraulic resistances after water rinsing, water backwashing and chemical cleaning of the fouled membrane. The results showed that the reversible fouling (cake formation) contributed to more than 80% of the total resistance. The filtered beer quality was checked after each run and it was found that the ceramic membrane successfully removed almost higher than 99.7% of haze compounds without any significant reduction in essential beer components. This indicates that the ceramic membrane crossflow filtration, regardless of very low permeation flux, appears to be a feasible substitution for the traditional Kieselguhr filtration in beer clarification