We visited the Westvleteren monastery - or at least the adjacent bar - in summer 2007, and we picked up a few bottles, at a very reasonable price, in Bruges, which we finally broke into in May 2008. The beers are widely reputed as being among the world's finest, although we do sometimes wonder if that's as much because they are hard to get as anything else.
We started with the Westvleteren Blond (5.8% abv), which is the beer that the monks themselves are apt to drink. It has a wonderfully intense aroma, with hints of honey, and there's a faint hint of honey in the taste, too. It's a complex beer, crisply carbonated with a large number of bubbles on the tongue. There were some disagreements as to whether it was sweet or dry, and while we agreed that it had some herbal/spicy qualities, some chose coriander and others cardamom as the dominant flavour.
We moved on to the Westvleteren 8 (8% abv) next. Again, the beer is intensely carbonated, and there was no disagreement this time that it was a much drier beer. The most prominent flavour was that of raisins, although there's no mistaking that this is a beer. Given the jump up in alcohol content, it was surprisingly light, even refreshing, in taste.
We concluded with Westvleteren 12 (10.2% abv),which has an exceptionally intense flavour, more obviously alcoholic even on the tongue. The beer had strong hints of sherry and port and fruit flavours. It was much sweeter than the other two brews, and tasted like a real after-dinner beer rather than a beer to drink with food. It wasn't as carbonated as its less alcoholic siblings.
After much mulling and swirling and glass exchanging, the consensus favourite was the Westvleteren 8: the final few sips from that bottle were in notably high demand.