Jazz producer and label founder Orrin Keepnews died March 1 at his home in El Cerrito, Calif., according to his son, Peter Keepnews. A cause of death has not been disclosed. He was 91. Keepnews, who started his career as a music journalist, co-founded the revered jazz label Riverside Records, along with partner Bill Grauer. The label's roster included jazz giants such as Bill Evans, Thelonius Monk, Wes Montgomery, and Sonny Rollins, and Keepnews emerged as a regarded producer in jazz. After Riverside folded, Keepnews founded a second label, Milestone Records, in 1966. He remained active after both labels ultimately became part of Concord Music Group, primarily working on re-releases of the labels' earlier titles. Keepnews earned four GRAMMY Awards during his career, including wins as a producer and album notes writer. He was honored with a Recording Academy Trustees Award in 2004.