Lesson 6 - Process Aids and Additions

We have already encountered beer haze and haze formation in some of our previous lessons. The Beer Properties unit will describe haze in detail. This lesson will explore how process aids can prevent haze formation or accelerate and remove the haze before packaging. The brewer can make a number of other additions to the beer post-fermentation that can enhance the quality, flavour, or processing of the beer. This lesson will cover these additions in detail.

We have previously described how at the end of fermentation, beer contains yeast and suspended protein/polyphenol complexes, which form non-biological hazes or a ‘chill haze’. We can use clarification process aids to assist the removal of these suspended solids through the process called precipitation.

Introduction to beer haze

When we look at beer styles and what defines them, haze may or may not play a part in the beer’s appearance. Wheat beer, New England IPAs, or unfiltered beers are characteristically hazy. However, traditional lagers and pilsners are typically very bright. We need to understand the causes of haze formation and how a brewer may influence these.

As you will see in the Beer Properties lesson on haze, there are two main forms:

• Biological haze occurs when bacteria or yeast multiply to a concentration that introduces haziness into the beer. This may also cause flavour changes,  such as sourness and sulphury notes. This occurs as their metabolites are excreted into the beer. Fortunately, since pasteurisation is common practice these days, its occurrence is rare.

• Non-biological haze formation is a normal event in beer processing and is necessary for the particulate matter to be removed and the beer ‘chill proofed’.

This lesson will focus on non-biological haze and the measures we can use to prevent its formation in the final pack. Biological haze is covered in the Beer Properties unit.