Lesson 5 - Beer Haze SAQ
This lesson enables you to test yourself on the material covered in the lesson on Beer Haze and to determine the level to which you have met the learning outcomes.
Suggested Response - Q5
** Explain the role hops play in beer haze.
Response:
Hops are normally in connection with beer flavour and aroma; however, they play a role in colloidal stability reactions too.
Hops contribute up to 30% of wort polyphenols. Many of the hop polyphenols mirror those in malt, e.g. catechin and procyanidins. These proanthocyanidins react with proteins to form haze complexes (unless they are removed during boiling).
The direct influence of the hop polyphenols on overall beer haze is seen in beers made with proanthocyanidin-free malt. This leaves the hops as the sole source of polyphenols. These beers are more clarity stable when made with supercritical CO2 hop extracts, which contain no polyphenols (as opposed to hop pellets which contain polyphenols).
Dry hopping during fermentation, maturation or even in package (cask ales), introduces a haze from the added hop polyphenols binding with proteins and metal ions. Clarity treatments can remove these; however, many brewers of dry hopped beers forgo this step in favour of naturalness.
Pre-isomerised or reduced isomerised hop extracts added later in the process at filtration, can be the direct cause of hazy beer if filtration is not fine enough, and hop oils added to BBT/FBT will cause haze.