Reducing microbial spoilage of beer using filtration

Filtration processes may be classified as either depth filtration or surface filtration. Depth filtration relies on a layer of porous media in which suspended particles in the beer are trapped within the media. Examples in brewing include filter aid filtration, sheet filtration and some forms of filter cartridge. Surface filtration normally refers to membrane technology. A thin layer of membrane has pores throughout the structure. This means that it is possible to achieve very exact filtration, perhaps enabling sterilisation, but typically the quantity of suspended beer particles that may be removed is less than for depth filtration. 

Sterile filtration. A filter sheet of suitable grade, although a depth filter, may enable effective sterile filtration to the satisfaction of the brewer. 

There is a need to design a sequence of filtration operations to maximise the throughput. For example, a relatively coarse initial stage will increase the duty on the second stage and therefore may not increase the total throughput. There is scope to perform this optimisation on the pilot or laboratory scale (Freeman, 1996). 

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Reducing microbial spoilage of beer using filtration... 

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