Troubleshooting - Homebrew Haze

I have been drinking the results of my most recent homebrew, Lady Liberty Ale, and while the taste profile was exactly what I was looking for, a light sessionable pale ale, the one problem with the beer is that it is quite hazy. While this is an aesthetic thing it is quite annoying and so I set about investigating the different causes of haze to see if I could make sure that I could address any problem in my process that could have led to this. Haze in beer can be one of two types, it can be permanent or temporary.

Lady Liberty Ale; tasty,
but hazy.

Permanent haze in beer is typically caused by two different kinds of process, biological or non-biological. Biological basically means that your beer has been infected. In this instance I do not think that the beer in infected, it has no off-flavours or smells and so I believe that the issue that caused the haze in this case is non-biological. If it was a biological infection the most likely cause would be poor sanitation, as sanitation is something I am very fastidious with when brewing I do not think this is the issue. Permanent non-biological haze is more than likely caused by an excess of starch built up due to an issue in the brewing process. This is a rare occurrence and so the focus of my investigation will be in relation to possible temporary haze, temporary haze can be caused by a number of issues.

Chill haze in beer is caused by proteins bonding with polyphenols and becoming insoluble, this occurs when the beer is cold and so as the beer warms they should dissolve once again. Chill haze in beer needs to be fixed through a process change, it is important to get your wort boiling quickly at the start of your boil to enable a good hot break, similarly it is important to chill your wort quickly post-boil in order to get a good cold break. Achieving these two breaks quickly should reduce the risk of chill haze in your beers. Another thing that will help solve this issue is to use a fining agent, Irish Moss or Whirlfloc can be added to the kettle 10-15 minutes from the end of the boil (personally I use Irish Moss).

Brewers don't make beer, yeast
does and healthy yeast = tasty beer.

The second possible cause of temporary haze could be from the presence of residual yeast in the beer, this is caused when yeast calls do not settle to the bottom of the fermentation vessel once fermentation is complete. You can solve this issue through a little patience, the typical conditioning period of 2 weeks can be extended and more time conditioning should encourage the yeast to settle out. If you are really concerned you can use another fining agent called Isinglass which can be added to the beer after fermentation.

Conclusion:

In my case I believe the haziness is due to two problems; chill haze and residual yeast. To test whether this was purely chill haze I poured a glass from the keg and left it for a few hours to warm up, although there was some improvement in clarity the beer still appeared hazy. Secondly I read back through my notes and noted some issues with the yeast, 1) it was right at the outer edge of its use by date and 2) it did not completely ferment out as I would have expected it to and finished a couple of gravity points too high.

In order to address these issues I will make two changes to my brewing process for future batches. To address the chill haze problem I will make sure to have a good rolling boil throughout the 60 minute boil (at times in the past I have had the tendency to switch off one of my elements and just maintain a weak boil). Secondly to address the issue of residual yeast I have decided to invest in a wort aeration system that will allow my to oxygenate the cooled wort prior to pitching the yeast. This should create a very healthy environment for the yeast to do its work in.

Further Reading/Reference:

Brew Your Own Magazine, Hazy Homebrew by Betsy Parks, May-June 2011, p. 11
The Home Brewers Answer Book, Ashton Lewis, p. 312-314
How To Brew, John Palmer, Appendix C - Beer Clarity, p. 277-281