San Francisco Symphony, Davies Symphony Hall, San Francisco

Whenever Michael Tilson Thomas takes the San Francisco Symphony on tour, audiences can expect a guided expedition through the conductor’s current preoccupations. To judge from a hometown preview last week, the orchestra’s imminent European dates promise a portrait of a musician with an unquenchable thirst for rediscovery.

The conductor’s championing of Copland’s mature output has brightened many a concert, but what will the continent make of his youthful and rarely performed Organ Symphony? Composed at the behest of pedagogue Nadia Boulanger, the work reflects the neo-classical imperatives to which the 24-year-old Copland was drawn during his Paris sojourn. The organ, fluty at one moment and grandiloquent the next, spices the orchestral texture.

The structure is unorthodox, with the central scherzo assuming the predominant place in the design, not for any obvious formal reason but simply because Copland’s imagination led him here.

For all the Organ Symphony’s heady invention, one listens in vain for any of the demotic flourishes – the open intervals, the folk sources, the dancey rhythms, the jazzy inflections – that secured Copland’s reputation.

But Tilson Thomas has always found the expressive possibilities in the composer’s less immediately ingratiating effusions, and here, with the collaboration of organist Paul Jacobs (at his most sprightly and decorous), and an orchestra that seems an extension of the conductor’s will, the feeling of nascent genius is too prominent to ignore.

The tour also inaugurates the SFSO’s Mahler year with an arresting reading of the Fifth Symphony. Returning to the composer at the completion of the San Francisco Symphony’s recording project, Tilson Thomas charts the work’s progress from funereal grandeur to ironic inebriation with a spontaneity that may surprise even those listeners who have followed this Mahler project through the 15 years of the conductor’s tenure here.

Now we are permitted expressive flourishes, subtle diminuendi, daring rubati, that suggest an almost obsessive relationship. Yet sentimentality, all too easy too summon in the Adagietto, is kept at bay. For Tilson Thomas, there is still much to say about Mahler and the discourse continues to fascinate. (

The programme is repeated on September 11 at the Lucerne Festival, www.lucernefestival.ch