It must have been tough for Isabel Charisius, the new, young viola player of the long-established Alban Berg Quartet. She has carved out a distinct place at the centre of its sound, ensuring the ensemble's survival at the highest level. And yet when the quartet's fans look at her, they also see who is not there: her charismatic predecessor Thomas Kakuska. Following his death from cancer 18 months ago, the quartet commissioned Grave (In Memoriam Thomas Kakuska) by Wolfgang Rihm.

The title of the piece, premiered in Vienna a fortnight ago, refers to the Italian or French musical direction to play slowly and solemnly. And yet it could perhaps also be read as the English noun. The sounds Rihm uses evoke hard-won breaths, heartbeats and an almost visceral sense of a body loosening its ties. Listening to the piece here felt like an intrusion on private grief.

The single movement opens with a soft, calm discord, but as the first violin moves into an angular, fragmented melody, the viola drops out and is conspicuous by its absence. Later, it assumes prominence, outlining a slow waltz before the four players are drawn inexorably together. The ending, which finds them back where they started, seemed inconclusive here; the players chose not to linger on a long silence but stood immediately to let us know the moment was over.

The Rihm was framed by two classics. Haydn's Op 20 no 4 quartet found first violinist Günter Pichler occasionally sounding offhand, but Beethoven's epic Op 130 was searingly focused. It seemed unreasonable to ask for an encore after the intensity of the Grosse Fuge, but the slow movement of Haydn's Op 76 no 1 was a suitably valedictory choice.