You’re acquainted with J. S. Bach, master of the Brandenburg Concertos and the St. Matthew Passion. But who knew he had a flair for opera buffa? Though not cataloged as such, his sparkling little gem of a cantata “Schweigt stille, plaudert nicht” (Quiet there, don’t chatter), BWV 211, gives us an inkling of what might have been. Here’s the skinny. Lovely Lieschen loves her cuppa Joe, Pop takes a dim view. It’s thought that the so-called “Coffee Cantata” first played at Zimmermann’s Coffee Shoppe, in Leipzig. Now On Site Opera brings it to The Lost Draft, a similar stronghold of the bean in Lower Manhattan, with tastings in counterpoint to the music. —Matthew Gurewitsch