It's here. It's beer. It happens once a year. This Saturday, September 20, marks the release of the venerable Zwanze. And although it sounds like some sort of infectious disease to be desperately avoided, craft beer connoisseurs line up by the thousands to experience this rare Belgian lambic produced annually at the legendary Cantillon Brewery on the outskirts of Brussels. A sort of Halley's Comet for the craft community, it makes a brief appearance at only a handful of select bars across the globe, flashing brilliantly before vanishing as quickly as it came. Tapping at just 23 locations in the United States, New Yorkers are fortunate enough to have two options for tomorrow's big day: Alewife in Long Island City and Spuyten Duyvil in Williamsburg.