There isn’t much that is predictable about Edgefest. That’s the way it’s supposed to be.

But one thing you can generally count on is that the festival - the Kerrytown Concert House’s annual celebration of creative improvisational music - uses its Saturday performances to weave together all of the various threads that the three previous days’ performances began.

Saturday was a culmination but, as is the nature of improvisational music, it was also a jumping-off point.

Edgefest’s 2009 theme was “Reeds of Change,” celebrating reed instruments and their place on the avant-music spectrum. And there were plenty of reeds on Saturday, with a particular emphasis on the bass clarinet, a criminally overlooked vehicle for jazz expression, which has finally received its due, at least in Ann Arbor.

Several Edgefest acts this year - Jason Stein’s Locksmith Isidore; Positive Knowledge with Oloyemi Thomas; and Saturday’s headliners, Hamster Theatre, from Colorado - featured bass clarinet prominently in their orchestrations.

But nowhere was that more evident than during a freewheeling, anything-goes jam session under a Farmers Market shelter, when Detroiter and Sun Ra Arkestra veteran Wendell Harris, Thomas, and Piotr Michalowski joined forces for a three-part improvisation under the “direction” of University of Michigan Professor Ed Sarath. The event, "Reeding: The Riot Act,” culminated with an all-star, 16-part improvisational extravaganza. Then came a smaller-group exploration, in which drummer Han Bennick led the ad-hoc group through its paces for a full-throated, seat-of-the-pants, poly-tonal journey that cooked more than enough to warm an otherwise chilly crowd on a brisk fall evening.

To hear these musicians laying it all bare as they traded solos out in the cold was to revel in the freeform nature of the music. The musicians created a joyous noise that echoed throughout Kerrytown.

Headliner Hamster Theatre concluded the evening with a strong set of accordion-infused jazz fusion that, for what it lacked in improvisation, made up for in a driving intensity that proved a perfect outro to four days of intense, challenging and, ultimately, beautiful music.

Do we really have to wait another year for Edgefest to start again?