So ... I'm experience some flavor-fade on kegged beer that's months in service ...
Miyagi stout's once-dominant (and wonderful) flavor is almost totally absent now, and was partially gone 3-4 weeks ago when I first started noticing it ...
The flavors from the yeast and the bittering hops and the maillards from one of the ingredients are ingredients using in the boil are still around, but the flavor from the main adjunct added at flameout are at a level low enough now that ONLY nitrogenating the beer brings them out ...
About a month ago there were noticeably absent right after pouring, while it was still really cold, but they would appear as the beer headed towards being on the warm side, close to room temperature ...
This is interesting to me, mostly because it seems to also be true of the hopping timing's ... the one's used during the boil seem to have a much better half-life of decay that the one's used at any point after flame-out ... for whirlpooling ... for dry hopping etc ...
I think I've read anecdotal accounts along the way that would suggest that flavors added in secondary tend to fade over time, too ...
It's looking like if you've made something "too aggressive," flavor-fade is your friend ... but if you started out just right, you might get to enjoy a gradual decline in your brew ...
In this case, I'm sad ... the now-relatively-absent flavor was righteously delicious, and I would have pounded that 2.5 gallons straight-away without blinking an eye ...
Guess it's not just IPA's that wilt/fade ... time to update my strategy a bit ... and I guess I'll seek some flavor science 101, aging info, etc ...
Interesting ... and a little bit sad, really ...
PS - Unfortunately, I'm going to have to hypothesize that this is the long-term punishment from not managing oxidation during racking op's ...