The Canadian pianist Louis Lortie has established a reputation as one of the finest exponents of the music of Ravel, so his survey of the waltz - tracing it from the relative simplicity of Schubert to its apogee in Ravel's wild excesses - promised to be illuminating. It was exactly that, not just for a dance through history every bit as inventive and mercurial as Lortie's technique, but for the insight it gave into his interpretive style.

Things didn't begin well. Lortie looked dismayed at the empty seats, hardly a good omen for the rest of Birmingham's Great Pianist series, and his selection of Schubert's Valses Nobles and Valses Sentimentales were, understandably, almost grudgingly delivered. But with Liszt, in the Valses Oubliées, and in the glittering, capricious arrangements of Schubert waltzes, Soirées de Vienne, and of Gounod's waltz from the opera Faust, Lortie was reminded of the impeccable programming logic and warmed to his task.

After the interval, he went out at a glorious tangent with Helmut Lachenmann's Five Variations on a (waltz) theme of Schubert, written in 1956. There were moments in this recital when Lortie's curiously prosaic and matter-of-fact approach balanced most oddly with his more overtly virtuosic showmanship, but that suited Lachenmann well - the work's alernating irony and elan were realised with great precision.

It also served to release a reservoir of pent-up feeling in Ravel's Valses Nobles et Sentimentales, sometimes languidly poetic in its homage to Schubert, sometimes teasing out a more jazzy hedonism. Lortie's coup was to forgo any applause at the end of this and launch immediately into La Valse. It exploded with an intensity and expressive force that was stunning, at once exuberant and decadent, and a total vindication of the eccentric route to this peak of the piano repertoire.