'Reaction in G': Pink Floyd's 1966 Instrumental That Foretold Their Improvisational Future

“Reaction in G” is a ghost in Pink Floyd’s early setlist – a live instrumental from 1966 that never made it onto a studio release. Only known from bootlegs and a single surviving recording, the track runs about seven minutes and relies on a simple, modal riff anchored by Roger Waters’ driving bass and Richard Wright’s organ drone. Syd Barrett’s guitar slips in and out of the riff, adding bent notes and feedback swells that feel closer to free jazz than pop.

What makes the piece a clear premonition of later Pink Floyd is its structure: the riff acts as a launchpad for open-ended improvisation. The band locks into a hypnotic groove, then breaks away into a collective, noisy middle section where rhythm and melody dissolve into texture –