Jenny Lewis has traded her hot pants for a fedora and sexy pop beats for sultry gospel-country rock rhythm. On her second solo album, “Acid Tongue,” Lewis looks to music reminiscent of decades past to carry her craft forward.

Lewis is best known as the redheaded goddess of Rilo Kiley. The twangy soul sound of “Acid Tongue” dramatically strays from the poppy spawn of the studio tunes of last year’s disappointing “Under the Blacklight,” a Rilo Kiley album with mainstream tendencies. But with “Acid Tongue,” Lewis has departed from glitzy studio sounds in search of a bolder Americana. Her new solo album offers raw music with country flavor that seems straight from the stage. At moments it sounds like it could have been pulled from parents’ record collections — the record tries to reach the charisma of Joni Mitchell, Neil Young or Crosby, Stills and Nash.

“Acid Tongue” digs deeper into genres that Lewis’ first solo album, “Rabbit Fur Coat,” merely alluded to. Songs jump from the country-rock of “The Next Messiah” to the soulful ballad of the title track. Lewis’ first solo album stuck close to the folky, acoustic style she has returned to throughout her career, but “Acid Tongue” traverses genres new to Lewis’ song writing but familiar to listener’s ears. These experiments with blues and country rock rhythms both complement her lyrics and allow her to explore vocally. Her voice has evolved into a gritty alto, and she isn’t afraid to embellish her lyrics with expressive, twangy vocals. “When did she come to detest you?” she condemningly asks in “The Next Messiah.”

The album summons images of musicians collaborating in a dark room hazy with smoke, calling on a time when rock still had soul. But the influence of another era doesn’t stop at sound. Lewis’ approach to the recording process yearns for the grass-roots collaboration of the seventies. It’s easy to imagine her on stage with these tunes, pounding out every note earnestly — the album was recorded mostly live, with little touch up in the studio. The approach results in self-assured musicianship that lyrically admits weakness and vice. Lewis has never been afraid to sing boldly about her regrets and fears of the future and it’s this irony that makes people love her.

On the title track Lewis again achieves what she has always done best. She invites listeners into the confessional, and pleads guilty to her failings: “You know I am a liar,” she sings. It’s her vulnerability that makes this song personal and accessible, but unfortunately, no other track reaches this sincerity and intimacy.

Lewis may croon words of loneliness, but she gets by with a little help from her friends (and family). M. Ward and Zooey Deschanel lend their vocals to the album. Lewis’ more-than-a-friend Jonathan Rice and her father and sister also make musical appearances. But it doesn’t always work out for the best: Elvis Costello’s wailing on “Carpetbaggers” defiles an otherwise enjoyable track. With all of the album’s collaborators and genre constraints, sometimes Lewis doesn’t sound like herself; listeners are left longing for the days of Rilo Kiley’s “More Adventurous” or “The Execution of All Things.” On “Acid Tongue,” Lewis loses some of the quirkiness that could’ve made the album stand out from other gospel/blues/soul/rock albums.

Lewis has a ways to go before conquering the bold genres of blues, gospel and country-rock that so many have shaped before her. She may not be Lucinda Williams or Carole King, but the direction of her solo career holds promise as long as she doesn’t hesitate to make her mark.