Lesson 6 - Process Aids and Additions

Beer clarity stabilisation treatments aim to remove one or both the haze precursors, protein, and polyphenols, by electrostatically binding with them.

In other words, some components of matured beer are negatively charged (such as yeast). The brewer must thus use an electrochemically positively charged clarification process aid (such as isinglass finings) to bind with them. By binding with haze forming components, the particle’s radius increases. Stokes’ Law then comes into play and increases the sedimentation rate of the newly formed complex.

These formed complexes are then filtered out.

The primary methods available to control haze are based on the following chemical interactions:

• Adsorption

• Precipitation

• Enzymatic hydrolisation

It is important that the treatment method does not remove other material or introduce flavour changes to the beer. They must be easily handled, leave no residue, and be cost effective. Commonly used examples are:

• Finings

• Silicates and silica gels

• Polyvinylpolypyrrolidone (PVPP)

• Tannic acid

• Enzymes

• Brewers Clarex

• Other treatments

Let us look at these individually in more detail.