Brewery techniques - The suitability and reality of membrane processes

This article is a follow-up to [F 3 260] on clarification techniques in brewing, and implements a comprehensive literature review [Doc F 3 261] on the potential applications of crossflow microfiltration by membranes in brewing, covering the period 1984 to 1998.

Membrane separation processes offer key advantages over conventional separation technologies, such as low-temperature product treatment and the absence of filter aids. These potentialities guide existing and potential implementations of membrane separation operations within the brewing process. The characteristics and contribution of crossflow filtration as a technological alternative for the four recognized applications of crossflow membrane filtration (i.e. wort separation after mashing, clarification of keg beer, production of alcohol-free beer and cold sterilization of clarified beer) are analyzed.

Two strategies for implementing membrane processes are studied:

• reducing losses during the brewing process (tangential microfiltration can be used to reduce material losses at various points in the process);

• the technological alternative to conventional solid-liquid separation techniques (of which two main applications are targeted: filtration for ageing beer and sterilizing filtration prior to packaging).

The objectives of each of the proposed plants are detailed, as are the academic contributions and their industrial development over the period 2000-2010. Also described are existing industrial facilities and their quantitative and qualitative performance for various solid-liquid separation operations, such as beer recovery from tank bottoms and clarification of stored beer.

• The subject of both academic and industrial research, membrane separation processes have undergone various improvements, in particular with regard to:the type of filter media and their physico-chemical surface properties;

• optimization of module hydrodynamics ;

• understanding clogging mechanisms (chemical nature of membrane clogging and entities present at the membrane-fouling interface, with a view to their elimination by an in-place cleaning operation).

In parallel with crossflow microfiltration processes, progress is being made in the use of alternative, regenerable filter aids – to replace...