KPLU All Blues host John Kessler has expanded "The Blues Time Machine," which has been a popular segment on his weekend blues shows. The weekly series tracks one great blues song through history - from its earliest recording to its latest and sometimes, with some surprising interpretations. "The Blues Time Machine" airs on KPLU on Fridays at 12:10 p.m. during the "Blue Plate Special," and on All Blues Saturdays and Sundays at 8 and 11 p.m.