Mozart’s music sounds very different on the smaller, softer pianos of his own period, and the Australian pianist Kristian Bezuidenhout is an expert on these historical instruments. The popular “Alla turca” finale of Piano Sonata in A Major, K. 331 has a puckish crispness more difficult to achieve on a modern Steinway piano. The opening “Adagio” of the Piano Sonata in E-Flat Major, K. 282 sounds more sparse and vulnerable on Bezuidenhout’s tonally less opulent instrument. Some of the most entertaining moments on this double album come in the four sets of variations included. Fleet of finger and alive to every twist of mood, Bezuidenhout makes a strong argument that these lesser-known pieces should be heard more often. His Mozart series, as a whole, is a reference point for recordings made on historical pianos.