RE: Orval: three different beers in one bottle?

This is very intersting! I'm in aging beers and wines as well too. Leffe (not really improved), Duvel (you could discuss if it improved, it's definitely "different") and Westmalle Absolutley improving the beer to name a few of them. It's very surprising for me to hear that Orval would change the taste towards Lambic tasts and gets sourness. I'll definitely try this! Apart from beer I've got wine I'm aging. I've been opening a chateau Branaire from 1976 for my birthday last month (Grand Cru Classé 1855) and recently I've been opening an Cotes de Castillon (Bordeaux) and Minervois (south of France) from the year 2000. All splendid wines and definitely worth to try and to see what the evolution was after all these years (well, the Chateau Branaire I didn't taste at the time as a young wine obviously, but the two others I did) !LUV