"All of a sudden there's countries calling that never would've entertained the thought of an American metal band playing in front of their kids," the band's then-bassist recalls of 1991 album's popularity.

Jason Newsted is certainly busy these days launching his new, acoustic-oriented Chophouse Band and the adjunct duo Would & Steal. But you can bet the former Metallica bassist is as attuned to this week's 25th anniversary of the group's Metallica, aka The Black Album, as anyone else in the world.

"Yeah, in my garage I have a bunch of old Metallica posters and stuff, banners kids made and different things like that," Newsted tells Billboard. "We just came home the other day and I look over and there's a poster for the album sitting in the back that says 8/12/91. I'm like, 'Holy crap...' I said to my wife, 'Y'know, that's 25 years,' and she's like 'Oh my gosh...' But it could've been about three weeks ago -- that's how I feel about the music."

Metallica was Newsted's second album with the band after joining in 1986 to replace the late Cliff Burton, and it was, of course, the group's worldwide breakthrough, selling more than 16 million copies in the U.S. alone. Newsted's main memory of making the album, meanwhile, was of a band taking on new creative challenges in the studio with an album that was considerably more direct and focused than its more long-winded, virtuosic predecessor ...And Justice for All.

"Everybody had built themselves up through hard knocks and scars and so forth to be ready for what was coming, to create this thing that was bigger than all of us and greater than any of us," Newsted recalls. "That includes all the people that worked with us, like the label and QPrime [management] and [producer Bob Rock]. [Rock] came in and he whipped us into shape about tonality of things and power of things and actual sound quality. We were ready for him, he was ready for us, the world was ready for the sound. We didn't sit down and say, 'It's gonna be like this,' no, but I think we pulled in somebody who could control us for a second, harness us for a second, and everybody put their nose to the stone and worked hard, like Metallica always did, and the floodgates just opened and we got the fruits from it. I'm really proud of what we did."

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Newsted's favorite song on Metallica is "Sad But True" -- "Just because of the weight, the six-string bass and that big, big bottom," he says -- but he also has a particular pride in "My Friend Misery." "It was the bass, by itself, introducing that song, which was not the easiest thing to do at that time within that band," he explains. "That was a moment where those guys kind of bowed and said, 'Here you go, man, put your song on there,' being the guy who came up with that; as opposed to being part of the team, I got to be myself for a minute there, which was a real accomplishment."

Newsted's other great memory of the Metallica album cycle was the worldwide territories it opened for the band. "That's the biggest deal about that. We worked so hard on the record for so long, and to take that music around the world like we did was really, hugely powerful," he says. "'Nothing Else Matters' was, like, No. 1 in 35 countries the same week or some sh--, and all of a sudden there's countries calling that never would've entertained the thought of an American metal band playing in front of their kids, and they're calling us up 'cause they know they can make a bunch of money because it's so freakin' popular at the moment. So we got to do a bunch of pioneering and be the first heavy band to go to a bunch of those places. That's what I remember the most."

Amid the Metallica bonhomie, meanwhile, Newsted is putting the pedal down on his new acoustic projects, including five West Coast dates booked for September with plans for more around the country. He's using a corps of musicians from his four Chophouse studios -- at home in Northern California, in his native Michigan, in Montana and in Florida -- with a repertoire of folk and country material as well as more contemporary material rearranged for an acoustic setting. The acoustic direction was inspired by private shows Newsted played with fellow musicians at his California Chophouse, as well as some documentaries about American roots music and musicians and songs he played for his ailing mother back in Battle Creek, Mich., who passed away earlier this year.

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"It's stuff I've been playing for 20, 25 years," Newsted says. "I've been collecting these songs and now I'm kind of taking them out in a more public way than I have before. It's important to come down from that heavy music for a second and getting to take a breath again and really do something with these wonderful, wonderful songs. Fun is the key -- fun, fun, fun. No more grind. I don't want to put that on myself anymore." Newsted has no recording plans for the Chophouse Band or Would & Steal just yet, though he's written some originals for the groups as well. For now, he's happy to let the music be spread by word of mouth -- or even social media -- and he may adapt some Metallica material for the performances too.

"I have been messing with it, like 'As the Crow Flies' or something like that," Newsted says. "It's not as easy as I thought it was going to be. You can't just slow down the tempo. It's got to be a real change of flavor to do it appropriately. I want it to be equally cool if we do something like that."

Newsted reveals he also had an offer to write a memoir but has put the brakes on it for right now, though he's not ruling it out for the future. Nor does he feel Newsted, the heavy band he operated from 2012-14 -- including an EP and album and some live shows -- is permanently finished.

"I was trying to take on too much stuff at once. You can only do so much and make it work right," Newsted says. "I won't call it over 'cause I did write a whole 'nother record, but it just hasn't been put together. It hasn't been recorded all the way. It's not ready for the people. That's something that's just on the back burner right now."

Newsted's upcoming tour dates:

9/2 - Crystal Bay, Nevada @ Crystal Bay Ballroom

9/7 - Santa Cruz, CA @ Moe’s Alley

9/8 - Mill Valley, CA @ Sweetwater Music Hall

9/10 - Napa, CA @ Silo’s

9/17 - Sebastopol, CA @ HopMonk Tavern