Here’s the thing about freeform improv and jamming: It’s all about letting these long, wild pieces spin out and unwind for 10 minutes or more without lyrics and with no apparent unifying force — just sheer force of will blazing it along. The music is perfect both for listening intently, or as background music while your mind is on something else, even as you can’t quite help swaying or tapping to the sound of drums and bass. Which was precisely the sort of feeling delivered by the distinct collaboration of Blackberry Jam with DJ MetroGnome at the Jazz Kitchen last Wednesday as part of Midwest Fashion week.

After a blistering opening from Thursday night regulars Triology + 1 (one of the most reliable bands in the city, incidentally), the gang was on full force from the opening minutes. One of the things inherent in the jam genre is how readily it accepts unexpected outside influence. MetroGnome’s old-old-school jams from the deck overlaid the band’s instrumentations in ever-more creative ways.

The setup itself was something to behold; it was quite an experience to listen to MetroGnome whip out something obscure from 1987 or thereabouts, and the Blackberry Jam crew listened for a few bars before joining in, sometimes with long lazy bits that worked their way up to pace, other times blazing ahead with mad force.

And the solos! When most of the band backs off a bit and one takes center stage, it’s not sparks, but full-fledged fireworks. Wah-wah riffs from the guitar; bass lines right from the glory days of Sly and the Family Stone; keyboard rhythms coming from I don’t know where. The best bits, for my money, came whenever it all slid together so seamlessly you couldn’t even tell MetroGnome’s backbeats from the live music. This is great stuff, and it always keeps you guessing.