It’s more like a home movie than a modern music documentary. But that’s the charm of Grateful Dawg. Jerry Garcia and mandolin player David Grisman first met on the San Fran folk scene in the ’60s and remained friends for over three decades, getting together to play acoustic bluegrass music whenever Garcia’s band commitments permitted.

Directed by Grisman’s daughter Gillian, Grateful Dawg chronicles their partnership through live concert footage and, even better, relaxed and intimate jam sessions in Grisman’s living room. Their repertoire is vast, from old Bill Monroe tunes to Dead classics such as “Friend Of The Devil”, via bluegrass versions of reggae favourites such as Jimmy Cliff’s “Sitting In Limbo”. The playing is intuitive but earthy and their spirits became so kindred that they even ended up looking alike, provoking the endearing nickname “two beards of the same feather”.

The music is augmented by interviews that are moving rather than illuminating, as Grisman and others talk about what Garcia meant to them and their sense of loss following his death in 1995. But it’s the music that is the real star here?full of an easy and timeless charm that exists for no other reason than the shared joy of playing together.