Hot Tuna started as a Jefferson Airplane side project, formed by bassist Jack Casady and guitarist/vocalist Jorma Kaukonen, though it became their full-time band once Jefferson Airplane dissolved in '72. The duo has been collaborating for more than five decades, and they've got the stage banter and chatter down pat, plus instrumentals that find the two venerable musicians trading riffs and solos; Kaukonen's a preeminent picker who complements Casady's low-end prowess. They tread blues- and folk-rock territories with ease and much solid melodic input from mandolin player Barry Mitterhoff. by Leilani Polk