[Will's Swill]

You're all heart. 

[SpanishCastleAle]

There is a little blurb towards the end of Kaiser's Doppelbock recipe that says a similar thing that tomsawyer mentioned.  It's a chemical reaction with the higher alcohols in an acid environment.  It takes a while to happen:

After lagering rack the beer to a serving keg or bottle and age at cellar temperatures ( 10 C / 50 F) for another 2-3 months. During that time most of the dark fruit notes will be formed by reactions between the alcohols (especially the higher alcohols) and acids in the beer. Some oxidation processes contribute to that as well. Since it is a chemical process, it works better at higher temperatures. Hence the suggestion to lager only for 2-3 months and then take it off the yeast completely and age for another 2-3 months

[ccarlson]

Most of us seem to store at cellars temps for long periods of time. I've often wondered what the optimum temperature really is. Are you better off in the 60 F range or all the way down to just freezing, as in lagering? It would be interesting to take several bottles of a less than desirable beer and store them at various temperatures and compare after a few weeks. Which ages quicker?

[morticaixavier]

Most of us seem to store at cellars temps for long periods of time. I've often wondered what the optimum temperature really is. Are you better off in the 60 F range or all the way down to just freezing, as in lagering? It would be interesting to take several bottles of a less than desirable beer and store them at various temperatures and compare after a few weeks. Which ages quicker?

it's a balance thing. The higher the temp the faster the aging occurs. at low temps it will change much more slowly but will last longer before going over the edge. Higher temps will age it faster but it will go over the edge sooner

[thomasbarnes]

There are several perceptions for fusel alcohols: aroma, taste, and splitting headache.  I concur that the first 2 can diminish or disappear.  What about the third aspect?

Time + heat + O2 + fatty acids degrades higher alcohols into the equivalent esters/solventy esters. To the extent that esters aren't as serious hangover fuel as higher alcohols their headache-inducing power will diminish as well.