The sudsy celebration that started Portland's obsession with gathering to slurp tiny tasters of craft brews is back for its 24th year. These days it has metastasized into a juggernaut of an event featuring more than 80 breweries from across the country, live bands, food, home brewing, and drunken frat brahs. But at its heart, it's still just about more than 70,000 local and visiting beer lovers communing with their favorite beverage on the planet. Since 2009, Preston Weesner has given the fest's most committed übergeeks a more intimate set of sips in OBF's "Buzz Tent." That's where the local beer industry insider and "chugmaster" houses one-off kegs of the craft brew world's weirdest and wildest beers—the kinds of expensive, experimental suds that brewmasters have held onto for a number of years but don't have in enough volume to sell commercially. Weesner says he's excited to tap the lone keg of Full Sail's Old Boardhead Barleywine Ale, which brewmaster John Harris (the man behind McMenamins Terminator Stout and Deschutes Black Butte Porter) made back in 1995. Weesner is tasting more than 60 "buzz beers" in the course of the four-day fest, tweeting the names of the beers as he starts serving them. But he warns that when each special keg runs out, they're gone for good. "If you're not there when it gets tapped you might not get it at all…," he warns. "You might just hear how good it was."

GO: Tom McCall Waterfront Park, Southwest Naito Parkway between Southwest Harrison and Northwest Glisan streets. Noon-9 pm Thursday-Saturday, noon-7 pm Sunday, July 28-31. Free entry. $6 souvenir mug required to drink; taster tokens $1. General info at Buzz Tent tasters costs two tokens. Follow the Buzz Tent on Twitter: @OBFBuzzTent to find out what they are currently pouring.