Champagne stirrers operate by two mechanisms&colon; agitation and nucleation. At a laboratory scale, mixing is achieved by magnetic stirrers or by simple hand-shaking. The Soul Stirrers, Staples Singers, Buffy Sainte-Marie and Peter, Paul & Mary all covered Johnson. The song was aiming for a sound similar to Cooke's former group, the Soul Stirrers. To reduce this inhomogeneity, one or more "tuners" ("stirrers") are used. He also sang with The Soul Stirrers briefly after the departure of Johnnie Taylor. The cast also included Morgan Freeman as well as members of The Soul Stirrers. Foster would stay with the Soul Stirrers until 1963. During this time, Franklin would occasionally travel with The Soul Stirrers. The Soul Stirrers were an American gospel music group, whose career spans over eighty years. That innovation led the Soul Stirrers, while still called a quartet, to acquire five members.