Introduced in late 2007, the "Smokestack Series" joined Boulevard's family of beers with year-round, seasonal, and limited edition lines of artisanal selections packaged mostly in 750 ml bottles, while some are also available in 12 oz. bottles and on draft. These bold, complex varieties were inspired by Belgian Trappist beer, and share several characteristics including their higher alcohol content. Year-round Smokestack beers include "The Calling" double ipa, "Long Strange Tripel", "The Sixth Glass" quadrupel, "Dark Truth Stout", "Tell-Tale Tart" a slightly sour ale, and "Tank 7", a farmhouse ale. Additional Smokestack beers have been released, including some limited release and some that are available year-round.