Out Dec. 4, the newest edition of the GarciaLive series showcases Jerry Garcia and Merl Saunders’ May 21, 1971 gig in San Francisco.

Garcia and Saunders’ palpable musical chemistry was rounded out by Martin Fierro on saxophone and Bill Vitt on drums, and to stoke excitement for the release, fans can now listen to the show’s 16+ minute “Keystone Korner Jam.”

As press release notes, the wide-spanning improvised segment is a “funky jazz-fusion romp,” and “while Saunders is credited with teaching Garcia ‘regular, straight’ music, there’s certainly no evidence of anything mundane here.”

Pre-order GarciaLive Vol. 15 here.

Listen to the “Keystone Korner Jam” in crispt 1080p audio below: