POP MUSIC REVIEW : Venerable Hot Tuna Takes Time to Cook : After a cold start with thin and bland vocals, the blues-folk band took its performance into high gear at the Coach House.

If you went fishing for some good music Thursday night at the Coach House, it took lots of patience to catch some Hot Tuna that you weren’t tempted to throw back.

For the first hour or so, Hot Tuna, the blues ‘n’ folk roots band that spun off from the Jefferson Airplane more than 21 years ago, sounded more like cold mackerel. An opening segment of electric blues had little heat or cohesion. But by the end of the night--and, at more than three hours, it was a long night--mainstays Jorma Kaukonen and Jack Casady and their two sidekicks in the current Hot Tuna lineup had managed to fry enough fish worth savoring.

Part of the problem during the early going was the poor match between Kaukonen’s singing voice, which is thin and dry as parchment, and the stormy blues settings that surrounded it. Things got worse when rhythm guitarist Michael Falzarano took over lead vocals. At least parchment has some texture, which is more than you could say for Falzarano’s bland, barely tuneful husk.

The one highlight early on was “Death Don’t Have No Mercy,” a quiet, dire blues by one of Hot Tuna’s chief early influences, the Rev. Gary Davis. Kaukonen’s attenuated voice was perfect for a song full of dread and resignation. But his real expressive means is his guitar, and his six-string cries and moans on “Death Don’t Have No Mercy” drove home desolation so deep that the song could have served as a blues for the people of Iraq.

Instead of building on that fine moment, though, Hot Tuna segued right into a terrible rendition of “Bring It on Home to Me,” courtesy of the dull-voiced Falzarano, who spelled Kaukonen vocally on several songs throughout the evening. It didn’t help that Kaukonen had put down his guitar and switched to lap steel, which he played with far less imagination and assurance.

Soon came a lifeless version of “It’s Alright With Me,” a Kaukonen original that is one of the highlights of the band’s new album, “Pair a Dice Found.” The recorded version is about holding on to zest for life, even when the world seems about to cave in. The slogging stage rendition sounded as if the band had decided to cave in after all. By that time, Hot Tuna already had put in what would be a full evening’s work for many bands, and a bad one at that. But instead, the band set about putting in two more hours of very good work.

The key move was a switch from electric to acoustic guitar settings; a sequence of songs based in the bouncy, ragtime-influenced blues that dominated Hot Tuna’s earliest work brought life into the show. The first spark came when Kaukonen’s guitar raced Casady’s bass through an up-tempo passage of “Hesitation Blues.”

Having righted itself with light-stepping blues, Hot Tuna gathered force with graceful, folk-based songs that took on a stately, elegiac cast, peaking with “Good Shepherd,” an oldie from the Airplane days.

Again, Kaukonen’s limited, ungainly voice proved evocative on the material. With his nasal, wizened tone, the scraggly bearded, bony-faced musician could have been a long-suffering farmer who has seen too many hard winters and parched summers, yet still hopes for good growing weather in seasons to come--an image in line with the chastened but unbowed emotional tone of much of Hot Tuna’s folk-based repertoire.

The show’s last sequence was devoted to proving that this version of Hot Tuna could play some good, rocking blues, after all. A crunching “Rock Me Baby,” one of the show’s many blues chestnuts, found Hot Tuna in fine form. Casady, as he did all night, laid down a rumbling, fast-moving bass part that made up in mass and force what it lacked in sharp articulation. It served as a firm bed for Kaukonen’s guitar work, which was as beautifully articulated as it was tonally varied, as he shifted between finger-picking and a plectrum.

Overcome by the bass, Falzarano’s rhythm guitar parts were more subliminal than apparent, but if nothing else they added some extra layering to what otherwise would have been a basic trio sound. Drummer Harvey Sorgen was an energetic, animated presence. His smiling enthusiasm was a help, since Casady and Kaukonen are both reserved performers who concentrated on their playing and relied on musical intensity to make up for an absence of showmanship (Charlie Tuna used to say more in a 30-second commercial than Hot Tuna said in more than three hours of all play, no talk).

Once it reached a good level of intensity, Hot Tuna kept on playing--and playing, and playing some more. Those who hung in until the end got to hear a storming, swirling bit of blues-psychedelica and an encore version of “Parchman Farm” that featured Kaukonen’s most biting vocal of the night.

Far Cry, the Los Angeles band that opened the show (and recently signed with Hot Tuna’s label, Epic Records) is fronted by a singer, Joan E. Jones, who has a vocal reach worthy of the group’s name. At times Thursday night, she sang in a countrified style that fell somewhere between Exene Cervenka and Maria McKee; at others, some Rickie Lee Jones jazz inflections crept in. The band went for sparse instrumentation that left several songs sounding unfurnished.

On first listening, Far Cry’s songs were not as grabbing as its lead singer’s voice. Jones resorted several times to sustained, stratospheric (and on-key) cries that were impressive, but also overdone.