Investigation of rotating and vibrating filtration for clarification of rough beer

A dynamic filtration technology, called rotating and vibrating filtration (RVF technology), has been investigated for the clarification of rough beer. The module was divided into two parallel cells including flat disc membranes fixed onto porous substrate which drained the permeate, and impeller-shaped rotating bodies attached to a central shaft. Experiments were carried out at pilot scale and under industrial operating conditions (temperature regulation: 0-4 degrees C, CO2 pressure: 1000-1500 mbar) with two different rough beers (lager beer type, 11 degrees and 15 degrees Plato) and a model beer (yeast suspension). In a first step, the radial additional pressure and the core velocity coefficient were determined. In a second step, the technology was evaluated with regards to qualitative (pH, haze, dry matter, yeast concentration, colour, bitterness, carbohydrates, proteins, polyphenols) and quantitative (flux, retention rate) criteria versus mean pore diameter. Finally, the performances versus the volume reduction factor were specifically scrutinised with real and model beers. RVF technology demonstrates high performances in terms of flux as well as producing a clarified beer of good quality (EBC norm). Overall results were compared to recent scientific literature and industrial practice. (c) 2006 Elsevier Ltd. All rights reserved.