Christa Schönfeldinger walked on stage carrying a pot of water: the accessory of choice for any player of the glass harmonica, a curiosity of an instrument that works on the same principle as licking your finger and running it round the edge of a wine glass. Armonica, written by Jörg Widmann 10 years ago and here receiving its UK premiere from the BBC Philharmonic, is not a concerto, but the pure, unearthly sound of the instrument plants the seed of the piece, along with an equally prominent accordion, and colours it throughout.

Time slows down. The orchestra seems to breathe in slow, massive throbs, the sound gaining substance with each inhalation until the sleeping beast stirs and threatens to wake. Widmann layers up the instruments so that each expanding note cluster feels denser than the one before, and the result is a mesmerising, sonically fascinating piece – even if at 15 minutes it perhaps takes a single idea a notch too far.

The great exhalations of the Widmann found an echo in the massive waves that crash throughout Sibelius’s prelude to The Tempest, which opened a second half devoted to the Nordic music that is conductor John Storgårds’s speciality; the orchestra was also red-blooded in the clashes between warmly woven order and military-drum chaos that drive Nielsen’s Fifth Symphony. However, in between, Schumann’s Violin Concerto was less convincing, featuring direct playing from soloist Thomas Zehetmair but stuttering momentum, and with the orchestral melodies failing to sing. Can anyone make this problematic piece work?

• Available on iPlayer until 31 August. The BBC Proms continue until 10 September.