Flute sonata in B minor

We know of only a handful of flute sonatas by Bach, and of those only the Sonata in B minor has survived intact in a manuscript by Bach himself. The identity of the flautist Bach envisaged in 1736/37 for this demanding piece filled with subtleties is shrouded in mystery. But there is no doubt whatsoever that it must have been written for an excellent musician. In 1724, it took a passing virtuoso – Gabriel Buffardin – to tempt Bach into using the instrument in one of his cantatas for the first time in Leipzig.

For the weekly concerts with his Collegium Musicum, Bach often called on the cream of Leipzig University’s music students. One of them was flautist Jacob von Staehlin, a fellow student of Carl Philipp Emanuel. Von Staehlin left for St Petersburg in 1735, so he probably did not play this sonata. But a later letter shows that he had really enjoyed playing flute duets in Leipzig with Carl’s younger brother Johann Gottfried Bernhard. This third Bach son, born in 1715, is barely mentioned in the Bach literature. This is hardly surprising, as he died young and no compositions are known by him. But it is not inconceivable that this son of Bach may have been the performer of the Sonata in B minor at the age of about twenty-one.

The fact is that although Johann Gottfried was very gifted musically, he also had a problematic character. Fifty years later, Von Staehlin referred to him in his letter as ‘windig’, i.e. a bit of a libertine. Johann Gottfried left his post as organist in Mühlhausen, after only a year and a half, leaving behind debts that his father cleared for him. Bach then found a new job for his son in Sangerhausen, from which he fled after a year, this time to an unknown destination, once again leaving debts behind him. Things did not turn out well for the black sheep of the family. In January 1739, Johann Gottfried enrolled as a law student in Jena, but he died four months later. Who knows how many more flute works Bach might have written had his son lived longer?