If music be the food of life, then Hoots and Hellmouth is about to serve up its second helping of sustainable sounds.

The all-acoustic but often raucous Philadelphia band - whose principal members are songwriter-guitarists Sean Hoots and Andrew "Hellmouth" Gray, plus mandolin player Robert Berliner - is releasing its sophomore album, The Holy Open Secret (***), on Drexel University's Mad Dragon label on Tuesday.

Last month, the musical locavores concluded a rambunctious performance at the Fishtown Shadfest in Penn Treaty Park with Holy Open's haunting rumination "Roll, Brandywine, Roll," and a heartfelt signoff from Hoots: "We're from here, and you're from here, and that's beautiful."

Tonight and tomorrow night, the band, whose music often leads to thoughts of dinner - its songs include "Home for Supper," "Forks and Knives," both off its 2007 self-titled debut, and "Dishpan Hands," off Holy Open - will be back to celebrate the new CD's release with headlining gigs at Johnny Brenda's, in Fishtown.

Hoots and Hellmouth came together in 2005 as part of the West Chester University music scene that produced Dr. Dog, the Philadelphia indie heroes whose American Diamond studio in Kensington the group used to record the new album. And what was The Holy Open Secret that they discovered there?

"Wouldn't you like to know?" says Hoots, the band's 33-year-old, redheaded leader, who studied philosophy and religion at West Chester and has worked as a cook, most recently at the Morning Glory Diner in South Philadelphia. "It's a secret."

He's kidding. Hoots was sitting down to talk, along with Gray and Berliner, on a rainy afternoon this week. They were in an empty retail space in Center City where Gray, 30, a part-time construction worker, was on his lunch break.

The album's title comes from a passage in the scientific writings of 19th century polymath (and Faust author) Johann Wolfgang von Goethe.

"It's the mystery behind what you claim to know already," explains Hoots. "It's the hidden secret that's out in the open. You can look at a flower and study it and pull it apart. But you still don't know what makes it alive."

That sense of curiosity and wonder courses through the band's music. The new album grabs the listener with Hoots' finger-snapping rallying cry "You and All of Us," before drawing one in with Gray's quieter, contemplative tracks such as "Ne'er Do Well" and "Three Penny Charm."

The group will head out in the fall on a "harvest tour" of community-supported agricultural farms. (The band's revolving bass chair, currently held down by touring member John Branigan, has elicited humorous comparisons to the roster of spontaneously combusting drummers of Spinal Tap.) Though they wield acoustic instruments, don't mistake the group for wimpy singer-songwriter types.

The acoustic band was formed out of the ashes of two electric ones: Hoots and Berliner's Pilot Around the Sun, which released three albums on the Chester County punk label Creep Records, and Gray's Midiron Blast Shaft, a metallic unit described by a Baltimore blog as having "the stage presence of an angry rhino . . . and the shortest cut-off jeans ever."

In 2005, Gray, a West Chester grad, started playing acoustic shows with Hoots at Fennario's Coffee and Tobacco in West Chester. While working as an English teacher, Gray borrowed the stage name "Hellmouth" from an ex-girlfriend's description of a salty-tongued roommate.

Along with Berliner, a University of Delaware grad who met his bandmates while bartending at the Iron Hill Brewery in West Chester, they went on a 10-day tour that year. And they realized that they could deliver their songs with as much foot-stomping energy without plugging in as they did when they had the volume turned up to 11. "We went out with a bunch of songs," recalls Hoots. "And we came back with a personality."

"On the surface, it's extremely different," says Berliner, 33. "With Pilot, we had electric guitars, very loud amps, and a drummer that played very loudly. It was an alt-rock band with R&B and gospel influences, and a very high-energy stage presence.

"Now we're an acoustic band, but we incorporate some of those same elements, with a very energetic stage presence. It's a different sound, but the same attitude."

"With less ringing in the ears," says Hoots, who, along with Moby and Citizen Cope, will speak on the panel "Does Radio Still Matter to the Artist?" at the Non-Comm radio convention today at World Cafe Live, hosted by WXPN (88.5-FM).

For Gray, the decibel level is beside the point. "Whether it's loud or soft or whatever," he says, "if it's emotionally cathartic, I think that's how it's similar."

Terry Tompkins, the president of Mad Dragon, who also managed Pilot Around the Sun, praised the band's work ethic - it will play 150 shows this year. Tompkins says that long before Hoots and Hellmouth demonstrated the impressive growth as songwriters that's apparent on Holy Open Secret, "the gusto of the live performance has always been there. With two acoustic guitars, a mandolin, and a stompbox, they've really created a sound that can hold its own with anyone, even without a drummer."

The basis of that sound is in the group's passion for rambunctious American vernacular music. Before Hoots and Hellmouth came together, "I had started really digging into old-timey and Appalachian folk music," says Hoots, citing an LP by the Stanley Brothers bluegrass duo that he picked up at a flea market, "almost as an attempt to reconnect with where my roots were coming from."

Until his father's job as a chemical engineer brought his family to Exton when he was 15, Hoots lived mainly in the Carolinas and Virginia. And the now-nonreligious songwriter says he "grew up in nondenominational tongue-talking churches."

His growling vocals carry echoes of the Southern church. "That's part of my fabric, so it's something I'm constantly referencing."

This summer, Hoots and Hellmouth will play a number of festivals, including the Xponential Music Festival in Camden's Wiggins Park on July 25, before heading out on the road in earnest to try, in Hoots' words, "to enrich the communities amongst which we travel."

Before then, though, Hoots has a little traveling,of the cross-town variety, to do - moving from South Philadelphia to the Art Museum area. (Gray and Berliner live in West Philadelphia.) While packing the other day, he listened to Good God!: A Gospel Funk Hymnal, a compilation on the Numero label. In describing it, he inadvertently captured what he and his bandmates are trying - and at their best, succeeding - in doing with their own music.

"The feeling and the gut-level honesty of what they're putting out there!" he enthused. "It's undeniable, and undeniably human. And there's this connection we all can make . . . just guys screaming their guts out. It's so real."

Contact music critic Dan DeLuca at 215-854-5628 or ddeluca@phillynews.com. Read his blog, "In the Mix," at http://www.philly.com/philly/blogs/inthemix.