Bach's cantatas open a window onto the intensity of early 18th-century Lutheran piety. The text of No 199 begins with the image of a heart swimming in blood, then dwells on the anguished guilt of the sinner before he is reconciled to God in the joyful final aria.

Without the medium of Bach's music, some of these lines would be hard to take. But his settings transform them into something approaching universal experience, so that today's listeners can still find them profoundly involving.

The soloist in Florilegium's performances, the Dutch soprano Johannette Zomer, might not possess a perfect voice or technique but she captured much of the directness and simplicity of belief that lie at the heart of these pieces. She warmed to the sense of release in the last aria, and throughout the better-known Cantata No 82, Ich Habe Genug, with its constant longing for death, her confidence allowed her to find the key to the music's expressive power, while Alexandra Bellamy's dark-toned oboe playing manifested extraordinary sensitivity to Bach's melodic shapes.

Florilegium is a seemingly infinitely adaptable group, able to traverse whole swaths of the baroque and classical repertoires, and more. Slimmed down here to a chamber scale with single strings, its accompaniments were secure and measured. The all-Bach programme began with the Second Orchestral Suite. Florilegium's artistic director, flautist Ashley Solomon, tackled the tricky solo part. His delicate tone was never covered by the other players, and, though he took the famous final Badinerie too fast for comfort, he managed to find room for the odd flourish.

The evening's most exemplary playing came in the Fifth Brandenburg Concerto, realised in a vital yet unrushed account given special memorability by James Johnstone's perfect balance between freedom and control in his harpsichord cadenza.