Early evening in the hills of Siena's Val di Chiana, and the sun hung low over the 14th-century hamlet-turned-hotel, Locanda dell'Amorosa, deepening the natural glow of its pink brickwork. Further shades of blush emanated from the abundant blooms spilling from the circling walls' flower boxes. Then, throwing all of the rosy above into gorgeous relief was the verdant green of the gently sloping central lawn on whose lowest point stood the stage, from which the audience seating rose backwards and upwards in a perfect piece of ready-made grassy tiering.

Which is all to say that the second night of Incontri in terra in Siena left you in no doubt that this Tuscan festival boasts some impossibly picturesque open air concert locations.

Predominantly focussed around chamber music, the festival had opened the previous evening at its base, the equally picturesque La Foce farm estate and gardens, with a string quartet of young Jewish and Arab musicians from the Polyphony youth orchestra in Israel, who had received a standing ovation for spellbinding performances of Mohammed Fairouz's Named Angels extracts and Shostakovich's Piano Quintet Op.57, the latter performed with pianist Saleem Ashkar (who had opened the evening alone with Beethoven sonata opuses 22, 31 and 111 in anticipation of his Berlin, Prague and Osnabruck Beethoven cycles this coming season).

Second Night then maintained the focus on the musicians of tomorrow, Simon Over conducting London's orchestra of music conservatoire graduates, Southbank Sinfonia, in Beethoven's “Emperor” Piano Concerto with Italian pianist Alessio Bax, who next year takes over as the festival's incoming artistic director. The preceding Rossini and Mendelssohn pieces not only continued the youthful thread by being student works, but also brought an additional clever thematic crescendo to the table, Rossini being Italy's “little German”, followed by the Mendelssohn symphony with its Beethoven-influenced finale. Nice.

Still, this wasn't an easy-ride programme for an orchestra of musicians-in-training; with the Rossini they were handed not only just a chugging accompaniment, but also the responsibility for maintaining the pace, and the mood of operatic romp. Then, Mendelssohn's first attempt at a full-scale symphony is not a masterpiece, and thus a hard sell to an audience unless blisteringly well done.

This was at least a festival audience predisposed to enjoying themselves, though, and Over and his musicians did well. After a slightly treacly start, the Theme and Variations hit its stride as the variations kicked off, and although the whole was characterised more by politeness than pep – Rossini's trademark forward-pushing momentum was never indisputably established – the operatic feel was certainly there. Jordi Juan-Perez meanwhile leapt around the solo acrobatics with enjoyable humour, even whilst not all his top notes delivered on tone.

Mendelssohn's First Symphony then got off to a good, angsty start with some strong emotional gear-shifts, which made it all the more surprising that the third movement's Minuet and Trio sections weren't more contrasting; however, this did contain some lovely passings between sections, and in fact a feel for lines turned out to be a strength in general, as displayed in the finale's double fugue.

Then to the Emperor Concerto, and Bax's was largely a beautifully crisp, sharp, satisfyingly phrased performance. His capacity for softness and for evenness of touch came beautifully to the fore for the concerto's many top-keyboard pianissimo flutterings, as his strong relationship with the orchestra also reaped dividends, producing satisfyingly sympathetic chamber pockets amidst the surrounding symphonic excitement. As a result, the strings' less-than-tight delivery, and Bax's own occasional overbleeding of notes into each other, mattered not a jot to the audience, who registered their approval with the second standing ovation of the festival.

What with Bax's brilliantly despatched encore, György Cziffra's arrangement of Brahms' Hungarian Dance no. 5, it was a very satisfied crowd that finally picked its way back through the fields.