There aren’t very many trios out there with the improvisational chops that Scorch Trio has. Melaza, their latest effort, does nothing to thwart that idea, despite a change in the band’s makeup. Drummer Frank Rosaly has taken over for Paal Nilssen-Love, but he doesn’t miss a step coming into the fold. The playing here is dynamic and powerful, often as immediate in its punch as it is intricate in its wandering. Raoul Bjorkenheim’s guitar can shred or glide or cluster — hear him do all three successively on “Bambalan” — and Ingebrigt Haker Flaten’s bass is both a rumbling foundation and a curious, snapping oddity. Melaza can be a shock, but it’s also a delightful surprise all the way through. Vacillating between chaotic rundowns and syncopated runs, the band builds an off-kilter groove that never settles in, and you end up bedding yourself down in the sweet discomfort of it all. The songs here are all named after Puerto Rican slang words, and it’s a fitting trick the way they seem tossed off, even careless, when really they’re considered and carefully built. In the end, their wordless meaning runs pretty deep.