Many musicians have had lengthy careers in San Diego, but few could match the collective accomplishments of The Farmers, who appear at Humphrey’s Backstage Lounge tonight, Aug. 25. One of the most beloved bands in San Diego music history, the quartet’s mix of rock ‘n’ roll, blues and R&B makes it the ultimate roadhouse band, with a slew of original hits and a lineup of great covers. Though the band’s members had known each other for years and had played in various combinations since the 1970s, The Farmers first got together in 2002. An indirect offshoot of The Beat Farmers, who played the world’s stages between 1983 and 1996, The Farmers released “Loaded” in 2005 with a lineup that included the original band’s Jerry Raney and Buddy Blue on guitar, as well as Rolle Love on bass and latter-day drummer Joel Kmak. Blue’s death in 2006 and Love’s exit not long after found a revamped lineup comprised of Raney and Kmak, bassist Chris Sullivan and singer Corbin Turner. This lineup’s members have been part of some of Southern California’s most inspiring bands of the last four decades, including Glory (Raney), The Penetrators (Sullivan) and the Hitmakers (Kmak). The Farmers’ most recent album is 2009’s “Fulmination,” with studio work on a followup beginning this fall. Kmak said the appeal of the band is in its presence as a high-energy bar band, with a restless nature. Anything can happen at a Farmers’ show, including recasting of old favorite songs and medleys that can top 10 minutes — all while keeping the dance floor packed. “Every gig is different,” he said. “The songs change. There is freedom and trust between us as musicians, so the band is open enough to follow where ever Jerry might lead us.” He said one of the band’s most popular songs, “Aw Man, C’mon!” started as a jam session, while a Yardbirds/Animals medley can be expanded or contracted at will. He said that during the band’s five-year run with this lineup, it has gotten even tighter. Having played together for so long, the quartet practically has interband telepathy, even honing its older original material. “It’s not like we record songs and think, ‘That’s it, we can never do them different,’” Kmak said. “Our last album came out about a year and a half ago. As good as it is, the songs are still evolving. I wish we could go back and record them now. Of course, when you’ve played a song for a couple of years, they’re going to get better.” While the band is known for its high-voltage performances, it can also sneak in a slow blues song or a quieter moment in the set. “We’re not a ballad-heavy band, but when we do something like that, people dig it because Jerry can nail that stuff too,” Kmak said. While The Beat Farmers were a globetrotting band with a major label, landing appearances on “Letterman” and generating fodder for movie soundtracks, The Farmers have been more low key, with just a pair of tours through the Pacific Northwest and Canada to their credit so far. However, the band has a diehard group of fans that follows them from show to show. Kmak considers this to be a direct result of the band’s own excitement during performances. “We just love playing,” he said. “I’m 54 and I look forward to every second of every gig. And I think everybody in the band feels the same way.” Kmak noted that although time off from the band is rare, even when it comes, it’s often wasted. “When we have a weekend off, we all call each other and ask, ‘What are you gonna do?’ It’s a curse to our loved ones,” he joked. The Farmers perform at 9 p.m. on Saturday, Aug. 27, at Humphrey’s Backstage Lounge, 2241 Shelter Island Drive. $12. For more information, visit www.humphreysbackstagelive.com.