Stan's concern is epistemological: is the term even valid--can we know what it means to be world class; what are the qualities that describe world class; which beer can legitimately be described as world class. To this end, he quotes Jackson's definition:
“. . . no one can deny that a Premier Cru Bourdeaux is likely to have more complexity and distinction than a jug wine (Or, in the British phrase, “plonk”). A beer rated ***** [five stars] is a world classic either because it has outstanding complexity and distinction or because it is the definitive example of the style, and no matter whether everyone is capable of appreciating it; some people probably don’t like first-growth Bordeaux, either.”In these formulations, there's some benefit to chronology. So long as a beer has stood as the exemplar of style long enough, it doesn't actually have to win every single blind-tasting competition. Never mind how good Allagash's lambics become, they will not displace Cantillon's as the exemplar of style any time soon. We credit history.
My interest is slightly different, but related to this. I wonder about the mobility of world classics--how does a beer move on or off the list? One of Jackson's world classics is Anchor Steam. My guess is that this is a bit of bone-throwing. America had become a real hotbed of brewing, but he wasn't about to displace Paulaner Salvator, say, with a new-world doppel. So he gave us the signature example of an indigenous style.
Generally speaking, that's a good way to go. Let a beer wear for a while, see what the brewery does with it. If, after two or three decades, it remains one of the regular islands in an archipelego of regularly-changing examples of the style, that's worth a lot. Yet I wonder, is it possible for the gears of history to turn enough--however slowly--so that an immigrant brewery, the decendant of a venerable classic, may one day supplant the old country's hold on the style? Is it possible for a New Jersey pilsner to take the mantle from Pilsner Urquell? (We know how that old-world standard has declined.) This is not a question for judges, of course. These designations are much more anthropological. We commend classic status by slow cultural agreement.
Guinness is definitely not the tastiest draft Irish stout, but it is of course the world classic. A New Jersey pilsner? Maybe. I'm not holding my breath.