[HopDen]

I made a Belgian Style Dubbel in December 22' and kegged on Jan 23' This is the last of 3 kegs. That belgiany flavor that we get from "Belgian" yeast seems to have faded rather extensively. I used WLP500. The flavor that one expects from Belgian yeasts was very present early on when tapping #1 & #2 kegs. It is a guess but both were tapped and consumed from mid February thru easter, maybe the end of April so within 4 months of kegging.

This leads me to a quandary. Does yeast lose their flavor influence over time? Do the latent yeasts have a negative effect on the flavor compounds that are inherent? In other words, do they act like scavengers much like when they re-absorb diacetyl during a D-Rest?

[jeffy]

Maybe, but it could be that other flavor aspects increase over time, like oxidation.

[HopDen]

Maybe, but it could be that other flavor aspects increase over time, like oxidation.

I agree oxidation can have an effect on flavor but I am not convinced this applies to me here in so far as the beer tastes very good but has diminished Belgian flavor. I take great effort to minimize O2 ingress, both hot and cold side.

[dmtaylor]

You've basically lagered (stored for a long time) your Belgian ale.  It's long been known that long-term storage results in a milder tasting beer.  The same effect that you are seeing here is well known with Bavarian hefeweizen, everyone will say "wheat beers taste best young!"  The same applies though to really any style.  IPA is another example of course.

Oxidation can definitely be a factor, who knows what the oxygen level was in your finished beer when you packaged it, or whether there are leaks someplace in the system.  But oxidation is not the only factor either.  Time is a big factor.  And the chemical changes that come over time are extremely complex, there are dozens of chemical reactions happening at any given time in any beer, it is extremely complex and can be difficult to predict and replicate.