With over 100 cask beers from 18 different states, plus one from DC-based Capitol City, the Blackwell/W2 bar at GBBF has one of the largest ions of US real ale in the world.
And it's proving a big draw, according to deputy bar manager Jim Laws. "Some people go for the strength, but a lot are going for the hops," he said, noting that while the US is famed for its big hoppy IPAs - and it is International IPA Day today, after all - there are plenty of porters, stouts and others on tap too.
He added that the beers from bar sponsor Sierra Nevada have been going particularly well: "The Sierra Nevada beers have been flying out - we've got three on, the Pale Ale, the Porter and the Torpedo Extra IPA."
There's even been a few that weren't in the programme, due to last minute shipping changes. Lowell Beer Works is the house brewery for a small chain of pubs in Massachusetts, and its tasty 15% Godzilla sold out in just a few hours on Tuesday afternoon. Its smooth Brookline Weizen Bock was still available on Thursday, fortunately.
So how have the US cask beers measured up to the exacting standards of CAMRA's volunteer cellar staff? Overall they have done extremely well, it seems. "One or two gave a few problems," Jim said. "But considering they've had a heck of a journey that's only to be expected."
Around half of the 100 had already run out by late Thursday afternoon, but Jim said there were still several more casks to go up on the stillage - including some more from Sierra Nevada - never mind the ones that had already been tapped and would be ready for sale shortly.
"There should still be a good range by Saturday," he concluded. "You can never tell though, it depends how busy we get tomorrow."