Originally Posted by ChandlerBang
Interesting. I hadn't heard of this. Do you have a source? I always blast a secondary with co2 for a few seconds before racking anyway.
Chandler, this is the old "wine into vinegar" conversion, but with beer instead. I don't know if that was the reaction that happened in my case, but it definitely involved oxygen (I knew I was incorporating O2 since I didn't have CO2 to purge the secondary), and I knew the temp of secondary was too high, since I don't have a lagering fridge (yet). The resource was Google, and I stumbled on a website explaining the conditions for the reaction, and it sounded plausible that my conditions were perfect. It was so severe with one batch (I forgot I left it in secondary) that I had to dump the entire thing. A few times I noticed the really small bubbles after I transferred to secondary, immediately siphoned to keg, and drank the beer with a slight off taste. Now I only do primaries and straight to keg, and don't get any of this effect/flavor. I will soon have a lagering chamber and will go back to secondaries the right way...
Hope this helps.