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General Category => General Homebrew Discussion => Topic started by: cfleisher on February 26, 2011, 11:51:15 am

Title: Occassional diacetyl problem
Post by: cfleisher on February 26, 2011, 11:51:15 am
I've been noticing a strong diacetyl presence in several bottles of doppelbock that I bottled about a month ago. Weird thing is that it's not every bottle. Some of them seem just fine. Is this possible, or am I just making this up? If some bottles have a diacetyl problem and others don't, what accounts for it? My sanitation methods are pretty thorough (or so I thought.)
Title: Re: Occassional diacetyl problem
Post by: hopfenundmalz on February 26, 2011, 12:38:42 pm
If your beer was low in diacetyl when finished fermenting, you can get it from:
1. An infection, but you said you are on the sanitation thing.
2. Exposure to air at packaging.  O2 will oxidize the diacetyl precursor into diacetyl.  When I read that in "Yeast", I realized what happened to my Second Round Pilsner last year.  The keg was fine, and it scored high in the first round.  I got rushed bottling and did not purge the bottles with CO2, maybe was a little rough getting them filled.  I had bottled a few extra, and the one I drank after I got the scoresheets had enough diacetyl that I could pick it up, even with my medium high sensitivity to it.   Live and learn.

Title: Re: Occassional diacetyl problem
Post by: hopfenundmalz on February 28, 2011, 11:13:45 am
This is a good reference.
http://www.brewingtechniques.com/library/backissues/issue1.2/fix.html