Following up two unique, adventurous releases of acoustic Americana, accordionist/pianist Sam Reider takes an unexpected detour with Petrichor, an album of gorgeous solo piano meditations. The audio quality is superb, the music at once sweeping in scope and intimate in feel. One gets the sense of listening in on Reider’s musical diary, a song cycle inspired by his return to San Francisco after a decade-long stint in New York. The opening “Mirror Lake” sets a mood of dreamlike abstraction, while other pieces are more pattern-oriented, with steady left-hand ostinatos in the manner of classical etudes (“Petrichor” being the most technically demanding). The common thread is Reider’s boundless harmonic imagination, reflecting influences from Debussy to Ellington to Keith Jarrett (“Kansas” sounds like something Jarrett might improvise). His admiration for Ethiopia’s Emahoy Tsegué-Maryam Guèbrou—captured in the flowing, dramatically unfolding lyricism of “Emahoy”—is evidence of Reider looking beyond the usual Western touchstones for knowledge and creative guidance.