Mad fermentation scientist Bryan Greenhagen creates his highly regarded array of craft beers in Mystic Brewery’s home in a hulking Chelsea warehouse. It’s also the site of his taproom, where the expected assortment of dwarvishly bearded brew fanatics thoughtfully sip and discuss his latest forays into farmhouse-style ales, double IPAs and sour beers. But even if you can’t tell a porter from a barley wine, you’ll find something to relish among the products of Greenhagen’s distinctive, deeply personal vision.