Lesson 8 - Clarification – Filtration
This lesson discusses the process of beer clarification via filtration. The filtration process primarily removes suspended particles from the matured beer to produce a clear stabilised beer that is ready for packaging. This lesson also discusses the importance of this process, the different filtration technologies available to the brewer, and the impact of filtration on final beer quality.
Preface
In this lesson, we will explore the importance of filtration, its benefits to beer quality, and the requirements that will ensure it meets the needs of the brewery.
We will start with the main objective of filtration. After maturation, we must remove those unwanted beer components that would otherwise negatively impact the beer’s final quality. These components include:
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Chill haze components (proteins and polyphenols)
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Haze derived from late hop additions
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Yeast
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Micro-organisms
Filtration removes solid components from the beer (sometimes called ‘rough beer’ at this stage) during transfer from maturation to bright beer tank.
Filtration helps to stabilise beer and give it a polished, clear (‘bright’) appearance. It also removes elements such as dead yeast, which would otherwise create an unpleasant bready, yeast-bitten, off-flavour.
However, not all beers are filtered; this depends on the brewer or the beer style being produced. Smaller breweries and brewpubs often prefer to serve their beer unfiltered; they see no advantage to a clear appearance and feel that the filtration process may compromise the beer’s authenticity and flavour. In fact, brewers of several classic beer styles including hefeweizen, and many bottle-conditioned beers, consider yeast turbidity to be a defining style element and thus strive to maintain it!