At heart of Beethoven’s grandiose ‘Emperor,’ pianist Paul Lewis detects an image of grace

Interview: At the core of Beethoven’s “Emperor” Piano Concerto, says British virtuoso Paul Lewis, dwells a tenderness that belies the work’s outwardly heroic trappings. That lyrical middle chapter, he says, bespeaks the concerto’s true heart. “Liszt called the slow movement of the ‘Emperor’ an angel between two demons,” says Lewis, who plays Beethoven’s last and most exuberant piano concerto with the Chicago Symphony Orchestra and conductor Vasily Petrenko in performances Jan. 8-10 at Orchestra Hall.