MUNICH—Beer enthusiasts might want to keep closer tabs on the Catholic calendar. Two weeks after Fasching, or Fat Tuesday, each year, a short list of local celebrities gathers at the Paulaner cellar in Munich to watch an honorary braumeister drive a brass tap into a new keg. The content he unleashes is called "strong beer," and when it starts flowing, Starkbierzeit, or strong beer season, officially kicks off.

This is Munich's subdued and slightly delayed Mardi Gras of sorts. It's also described as the insider's Oktoberfest—there...