Hot Tuna Is at Home in Laid-Back Niche : After 20 or so years, the duo, which stands for bluesy, off-the-cuff music, is still a crowd pleaser. It plays the Coach House tonight.

Hot Tuna can be fish or fowl.

Over the years, the act anchored by Jefferson Airplane veterans Jack Casady and Jorma Kaukonen has been flexible enough to play as a relaxed acoustic country-blues duo, bring in guest musicians as the spirit moves, or expand into a full electric band.

During its initial run in the 1970s, and in a subsequent reunion that has seen Casady and Kaukonen tour together again for the past five years, Hot Tuna has stood mainly for loose, off-the-cuff music. The sound is steeped in rural folk and blues sources. The basic, unassuming approach is the stuff of barrooms and back porches.

The release last fall of “Pair A Dice Found,” Hot Tuna’s first album of new studio material since the ‘70s, has made things a bit more structured lately, Kaukonen said in a recent phone interview.

“This is the first time (since the duo’s ‘80s reunion) that we’ve done a real band thing, where the people on the tour are the people (who played) on the record. It’s the first time we’ve taken the time and the money and the trouble to do it,” said the 50-year-old guitarist, who will front a four-man version of Hot Tuna tonight at the Coach House.

Hot Tuna began more than 20 years ago as a way for Kaukonen and Casady to kick back a bit, step away from the pressures of life in the Jefferson Airplane, and play some homey country blues. As the first major rock band to emerge from San Francisco in the mid-’60s, the Airplane was committed to a program of musical innovation and a political agenda of anti-war, anti-Establishment broadsides. The band’s three main singer-songwriters--Marty Balin, Grace Slick and Paul Kantner--served as the steering committee. Kaukonen and Casady, who had first played together in their hometown of Washington, provided instrumental firepower.

Speaking in an amiable, gravelly voice, Kaukonen recalled Hot Tuna’s origins.

“Jack and I would share rooms. In those days, every hotel did not have a cable TV. We’d finish (a Jefferson Airplane concert), we’d go back to the room, and we’d play. Pretty soon we had a repertoire of stuff, and nothing to do with it.”

By 1970, Kaukonen and Casady had launched Hot Tuna as an outlet for their folk-blues excursions. What began as moonlighting turned into a full-time career when they left the Airplane two years later.

“By 1972, the Airplane, in my opinion, was just repeating what it had been doing,” Kaukonen said. “Everybody wasn’t talking to each other as much, and the vibe was different. I said, ‘I got into this business to have fun, and I’m not having fun.’ I was really getting schizzed out until I realized it was unnecessary. I was making myself nuts. It’s important for me to maintain a kind of equilibrium in my life. When things get crazy, I move on.”

Being an Airplane alumnus has given him surer economic footing than some other musicians who play acoustic blues, Kaukonen said.

“It really has allowed me to do what I want to do for years, and be self-supporting. On the other hand, it’s damaged my credibility among people in folk and blues circles who don’t know what I do.”

A while back, Kaukonen, said, Johnny Winter caught his blues act for the first time. “He said, ‘Gee, that’s pretty good. I thought you just played that psychedelic stuff.’ He’d heard me with the Airplane. He’d never heard me play acoustic or blues.”

Just as the original Hot Tuna was launched from the Jefferson Airplane, the latest Hot Tuna record sprang from Kaukonen and Casady’s participation in a Jefferson Airplane reunion tour in 1989. The Airplane stage show featured a Jack and Jorma duo segment of Hot Tuna blues. Epic Records executives liked what they heard, and eventually signed Hot Tuna. Kaukonen said the label wasn’t looking for a Hot Tuna that would fit contemporary-radio tastes by polishing its act.

“They were really good about it. They just wanted us to be ourselves. It’s not a Top 40 album, obviously. But we have a really interesting cross-section of fans. It’s not just aging hippies.” The audience also includes some youthful hippies--the sort of new-generation Grateful Dead fans who are attracted to Hot Tuna’s folk and blues influences and ‘60s San Francisco rock roots, and to a laid-back ethic that stands against slick contemporary conventions.

Much of “Pair A Dice Found” has a rough-edged camaraderie, as if the players--Kaukonen, Casady, rhythm guitarist Michael Falzarano, drummer Harvey Sorgen and keyboards player Galen Underwood (the only member not on the current tour)--had hoisted a few at the bar, then adjourned to their studio before the amiable rapport could wear off. At the same time, several songs reflect on urban decay and world discord. One number, Kaukonen’s “Ken Takes a Lude,” has some bitter lines about life in the music industry that almost seem shocking coming from the grainy, homespun, laid-back singing voice behind Jefferson Airplane’s gentle “Good Shepherd.”

“I’m not any kind of brilliant message songwriter. I just write about what’s going on in my life,” Kaukonen said, adding that the album’s socially aware material is not a deliberate move to balance Hot Tuna’s image as a good-time band. “There’s no really conscious image decision made here. Whatever people get out of what we’re doing is fine with me.”

Having crisscrossed the country from Washington to San Francisco, where he became a famous psychedelic rocker, to Woodstock, N.Y., where he has lived for the past seven years, Kaukonen said his next move will be to middle America.

After Hot Tuna finishes touring for the year, Kaukonen said, he and his wife, Vanessa, will move to a 119-acre farm they bought outside Athens, Ohio. Besides turning it into a homestead for raising a family, he said, they hope to establish a camp where youngsters can spend summers learning to play the guitar. According to Kaukonen, this plan is also based on a pattern from the ‘60s: “Wavy Gravy (one of the San Francisco rock culture’s resident jesters during the ‘60s) has run a clown camp in Northern California for 22 years. He has good classes for the kids. He’s my paradigm in this.”

Hot Tuna plays tonight at 8 at the Coach House, 33157 Camino Capistrano, San Juan Capistrano. Tickets: $19.50. Information: (714) 496-8930.

FOLK LIVES: Traditional folk music has long been the anemic stepchild of the Orange County music scene, but there are some hopeful vital signs registering of late.

Carolyn Russell, who used to stage concerts at her home in Garden Grove until city officials shut down the monthly series several years ago, is about to begin “The Living Tradition,” a series of folk music shows at the Anaheim Cultural Arts Center, 931 N. Harbor Blvd. Bob Blair, a locally based singer with a repertoire of cowboy songs, Civil War material and work songs, will play the first concert in the series on March 9 at 8 p.m., with admission $6 (free for children under 12). Singer-guitarist Bob Brozman has been booked April 13 at 8 p.m., with admission $8. Plans call for concerts the second Saturday of each month, promoted by Russell, Betty Glasser and the Occasional String Band. Information: (714) 535-3059 or (714) 638-1466.

In another development, a fledgling organization called the Folk Music Society of Orange County is trying to establish itself, with the aim of sponsoring concerts and festivals of its own. President Corinne Welch said she became involved in folk music about a year ago, when she took up the dulcimer. Noting how limited the opportunities were for hearing traditional folk in Orange County, the Huntington Beach woman decided last fall to launch an organization that would help foster folk music here.

Welch, an administrative secretary for the Ocean View Elementary School District, said the society’s first event was a jam session on Feb. 16 at the Anaheim Cultural Arts Center that attracted about 30 players and listeners. Plans call for jam sessions on the third Saturday of each month at the center. The 5 p.m. sessions will precede the monthly old-time folk dances and potluck suppers hosted at 7 p.m. by Carolyn Russell and her group, the Occasional String Band. The next jam will be March 16.

The Society’s immediate aim, Welch said, is to recruit members and raise enough money to begin sponsoring concerts in private homes--a staple of the Los Angeles County traditional folk scene. She also has a bigger, longer-range goal: “Maybe by the fall of ‘92, we’ll be able to have a folk festival here in Orange County and bring in some top names,” she said. “But to do that we’ll have to raise money.” Information: (714) 536-2743.

Meanwhile, Shade Tree Stringed Instruments in Laguna Niguel, the county’s steadiest venue for local and touring traditional folk talent over the past two years, has announced its spring concert schedule. Tracy Schwarz plays Cajun and Appalachian music March 16, with admission $12; Irish singer Mick Hanly performs March 23, admission $10; Local acts Cottonwood and Rob Hoyt play April 13, admission $8; Andy Irvine, former singer of the Irish folk band, Planxty, appears April 22, admission $14; the Swamp Zombies, a lighthearted Orange County folk-punk band, play May 4, admission $8; and the duo of Carol McComb and Ed Johnson appears, along with opening act Tom Long, on May 17, admission $9. The Shade Tree’s winter schedule ends Friday with a St. Patrick’s Day warm-up concert of Irish music by Golden Bough, with admission $9. All shows start at 8 p.m. Information: (714) 364-5270.