Think of the great J.S. Bach, and an image of “Bach the law-maker” springs to mind. One imagines a stern German bank manager in a wig, who’s just said “nein”. About his composer sons we’re much less clear. Times had changed, the dusty old laws of counterpoint were out, and (for CPE Bach at least), perfervid emotionalism was in. When he played the clavichord, we’re told he got so worked up that “drops of effervescence stood on his brow”.

There was no effervescence on the brows of the Orchestra of the Age of Enlightenment at this all-CPE Bach concert, as far as I could see. Nor on the brow of conductor Rebecca Miller, who shaped things with a nice blend of grace and urgency. But there may have been on mine, because the music was truly extraordinary, and genuinely unsettling.

The OAE offered five of CPE Bach’s symphonies. The first of them in Eb major launched off with a bustling and somewhat motoric busyness, which lulled us into thinking we were still safely in the Baroque. But then the bass did an odd side-slip, followed by an unexpected pause, then a loud chord appeared in the “wrong” place. Suddenly we were in uncharted waters, with no compass.

Of course CPE Bach wasn’t Schoenberg. The oddities always made sense eventually, but before light dawned there was a delicious and dizzying moment of uncertainty. The weirdest moments were in the junctions between movements, where often the new mood and tempo just started without warning.
The orchestra was careful not to make these sudden shocks too explosive. Too many blows to the nerves can become wearing. And in any case not all these original moments took the form of shocks. Sometimes they were rooted in a strange fevered pathos, as in the slow movement of the B minor symphony. In the F major symphony the slow movement had a tiptoeing, gaunt remoteness, very like some of Haydn’s slow movements.

Most surprising was the pastoral sweetness of the slow movement of that big D major symphony, which featured some beautifully poised trios and quartets from the woodwind section. The least startling piece of the evening was the Double Concerto for harpsichord and fortepiano. The graceful phrases passed back and forth between soloists Mahan Esfahani and Danny Driver were lovingly shaped, and the contrast between the harpsichord’s silvery tinkle and the fortepiano’s drawing-room intimacy was a delight.