When the band Lettuce crushes a groove, it’s packed with chemistry that was sealed across the quarter-decade since those funk-meisters met at a Berklee summer program, enrolled in school and jammed every night in their dorm.

“It’s like some camp we never got to leave,” bassist Erick “Jesus” Coomes says of the group, which coined its name after asking bands at college parties to “let us” borrow their gear and play. “How many people do you know that even have friends as long as we’ve been friends?”

Schedules and membership have shifted along the way. Coomes infiltrated the hip-hop hierarchy, recording with Dr. Dre, Eminem and Kanye West. Drummer Adam Deitch served with jazz guitarist John Scofield as well as rapper 50 Cent. Guitarist Eric Krasno and keyboardist Neal Evans launched the jazz-organ trio Soulive and are now off working on other projects. But Lettuce’s core family has remained true. “Nothing [else] gave us that feeling of fulfillment,” Coomes says.

“We’re all perennial students,” Deitch adds, citing their continual study of soul, jazz, funk, Afro-Cuban, West African and Brazilian music—as well as electronic textures. When Lettuce formed in the early ’90s, he admits, “We were kind of all over the place.” But certain influences were clear: Earth, Wind & Fire, James Brown and the Meters, in addition to hip-hop and the jazz-fusion of Miles Davis.

In fact, Lettuce just released Witches Stew, its recording of a 2016 live tribute to Davis where the band tackles the trumpet legend’s electric period in a ghostly, psychedelic way. “We gravitated toward that side of improvisation, mixing funk in that free-form sort of way,” Deitch says of the project spearheaded by trumpeter Eric “Benny” Bloom. “Miles sort of created that path.”

Indeed, while Lettuce often gets lumped in with jam-bands, the group mainly generates its heat from the bottom up through fierce ensemble precision, like a show band with greater depth. “We respect the simplicity of the hardest grooves in music,” saxophonist Ryan Zoidis says. “That’s what gets us excited. The solos and jams happen, but we can improvise together as a band just with grooves.”

“The simplest stuff is what stands the test of time,” agrees Coomes. “As a bass player, there’s a job you need to do, like a bridge that’s going to take everybody from one place to the other. You have to be that road, that pavement.”

He credits the “right place at the right time and being humble” for studio gigs through his affiliation with hip-hop producer DJ Quik. That’s the name that Coomes dropped when he slid backstage at an LA club to say hello to a nascent Kanye West—and ended up on West’s 2004 debut The College Dropout.

“He gets a little excited, and that gets confused,” Coomes says of West. “If you make something awesome, like a painting or sculpture or piece of music, it’s pretty easy to realize that it’s not you making this by yourself. The universe is spinning around you. You become awestruck at what’s happening through you.”

Sounds like how the Lettuce guys feel about an early 2018 studio follow-up to Witches Stew. “It got way out of our hands, beyond us in a good way,” Coomes says of improv-heavy sessions honed after concerts that included new originals. “What we’d do after the show usually is grab some food, hang out in the back of the bus and listen to the [live] recordings,” Deitch recalls. “I take a lot of notes on things that could have been better or that we should remember to record.”

Expect a taste of that new material when Lettuce rolls into the Paradise Rock Club on Dec. 28, with Berklee professor and guitar guru Jeffrey Lockhart sitting in for Adam “Shmeeans” Smirnoff, who’s tending to a new arrival in his own family.

The sextet also adds another element at shows these days: Nigel Hall both sings and plays keyboards on a permanent basis, contrasting the mostly instrumental brew with vocals that pump up the crowd. “We’re here to party, but we mean business,” cracks Coomes. “And we mean business, but we’re here to party!” ◆

Lettuce plays the Paradise Rock Club on Dec. 28.

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