From 1720 to 1741, Zimmerman’s Kaffeehaus in Leipzig was the home of the Collegium Musicum, a concert society originally founded by Telemann and later directed by JS Bach. Naturally its musical evenings often featured works by the two friends. The OAE presents an evening of music that may have featured at these coffee-fuelled gatherings, including a new reconstruction of a concerto of which J.S. Bach left only an intriguing eight-bar glimpse…