Jamming With moe.

The label is a mystery even to Rob Derhak. His group moe. (lower case and with period, thanks) didn’t arrive at the “jam band” title the usual way. The singer and bassist was never a huge Grateful Dead fanatic, and was initially inspired more by such punk-funk acts as Primus and the Red Hot Chili Peppers. He prefers hard rhythms to noodling.

The jam band label is a broad one, and while Phish, the current masters of the genre, can often drift into a jazzier bluegrass direction, Derhak feels more in tune with such ‘70s rock heroes as the Allman Brothers, who regularly stretched a four-minute pop song into a 20-minute live improvisational epic.

“There is definitely something going on,” Derhak says. “But it’s not like we all hang out in coffee shops together in the same town wearing the same kind of clothes.”

The band, which is set to perform Friday and Saturday at the John Anson Ford Amphitheatre, has been hailed by some critics for songwriting that is tight, hard-edged and accessible. The result has been two distinct identities for the quintet, one as a live improvisational band, another as musicians and composers in the studio.

Crafting tightly wound rock songs for recording has given crucial form and foundation to moe.’s live jams, preventing a drift into aimlessness. In one example, the 10-minute “Spine of a Dog,” which opens last year’s live “L” album, moe. edges far closer to a late-’60s rock wind-out from the likes of early Santana.

“There are definitely hooks in our music that grab you, but there are a lot of other things you have to look for yourself,” says Derhak. “It’s like watching a movie you really like five or six times--you see something new and different in it every time. I think people dial us up in that type of vein.”

Derhak says he has probably grown far more as a musician in the improvisational mode than he ever would have as a typical rock player doing the same songs the same way every show. “It’s like rehearsal every night,” he says. “It’s always learning new things all the time. If I was just playing bass in some pop band that played the same set and the same songs every night I don’t think I’d ever get any better.”

Along the way, the band has learned to create during these onstage jam sessions, and then to let those moments slip away. Trying to reenact any of those ideas later never quite works, he says. “Just let it go,” he explains. ‘Never try to re-create, otherwise it will blow up in your face.”

That isn’t how moe. began, when this group of one-time University of Buffalo students first gathered a decade ago to perform their versions of college-rock songs. By the time the band relocated to New York, moe. had progressed from sharing bills with punk bands to working in an unexpected improv mode.

“Initially, things changed pretty early on because we were trying to get gigs and we had to play all night,” Derhak says. “So we had to stretch the tunes out, and we didn’t have enough material.”

While his interest in the jam band forefathers of the Grateful Dead was minimal (“I went to a few shows because it was a good party”), Derhak says he and the band did find inspiration in the example of Phish.

“I was into Fishbone and bands like the Royal Crescent Mob and 24-7 Spyz,” he says. “Then I saw my first Phish show and it blew my mind. I didn’t even understand what they were doing; I was trying to catch on. They probably made me want to open up and improvise a little bit more.”

Band Has Its Own Label

The group is currently finishing a new album, “Dither,” for release in January on moe.’s own Fat Boy label. And songs from the album are already part of the band’s live repertoire.

“It’s a lot different from what you’ll hear live,” Derhak says. “We’re doing backwards loops and stuff like that. It’s stuff that we really wanted to do. It represents that piece of art at that time. I don’t think an album defines a band, and I don’t think our live show defines the band. Each particular thing should be taken at face value.”

BE THERE

* moe., Friday and Saturday at the John Anson Ford Amphitheatre, 2580 Cahuenga Blvd. East, 7 p.m. $19.50. (323) 464-2826.