Ohio-raised keyboardist talks discarded demos and the challenge of evolving

When My Morning Jacket released The Waterfall in 2015, band members said another album of material would soon follow. Singer Jim James recorded more than 30 demos for The Waterfall, and only 10 tracks made their way onto the album.

But that was two years ago, and while James released a second solo album, Eternally Even, in 2016, fans are still waiting for a new MMJ record.

“We had thought we'd go back in and finish a second record because we had so much left over,” said keyboard player Bo Koster by phone in late July. “It's been so long now that I think nobody wants to go back and revisit that stuff. We don't want to go back in time. We're different people now. In hindsight we probably should have just soldiered on and made a double record. It was a little ambitious to expect that we would revisit it.”

Koster said the band has some recording dates tentatively scheduled for the fall, but My Morning Jacket isn't rushing or forcing anything.

The Louisville band began as a cult folk/alt-country act in the late '90s and found a wider audience on 2003's It Still Moves, thanks in part to the track “One Big Holiday,” a “Free Bird” for the Wilco generation.

On 2005's Z, My Morning Jacket began messing around with new sounds, and on every album since, the band has surprised listeners with psychedelic experiments and genre-hopping tracklists.

“That's the cool thing about being in a band for a long time, but also the hard thing — for the band and for the fans,” Koster said. “People change. The things you liked 10 years ago, you don't listen to now, but your fans still want you to be that person you were 10 or 15 years ago. And if you don't evolve, you're not doing yourself a service, and you're not doing your fans a service because you're not being authentic and true to who you are. So it's hard to really know what it will be like the next time we get together and record.”

Koster, a native of Lakewood, Ohio, joined up with My Morning Jacket years ago on the It Still Moves tour after a mutual friend recommended him to the band. “It was kind of a lucky strike, honestly,” said Koster, who now calls Los Angeles home. “He'd been a friend for a long time, and I had just been talking to him at a party, saying I didn't want to end up being a studio musician or a guy who's a hired gun. I wanted to find something that was more creative and personal. He called me up six months later and said, ‘I think I found something for you.'”

When not touring or recording with My Morning Jacket, Koster plays keys on other records, like recent releases from Ray LaMontagne and Sam Outlaw and a forthcoming solo album by the Scissor Sisters' Jake Shears. He also co-produced a 2010 album by Delta Spirit.

“I always felt like I was good in that helper role,” Koster said. “I like being somebody's mirror to give them positive and accurate feedback.”