The newest member of the world-famous heavy metal group Metallica doesn’t sing or play an instrument—he makes whiskey.

Rob Dietrich was recently named distiller and blender of the band’s American whiskey brand Blackened.

Dietrich spent the last 13 years in Denver distilling acclaimed American single malt whiskey Stranahan’s. “Honestly, I absolutely love Stranahan’s. I love what I’ve helped build there and to me it’s one of the most spectacular whiskies in the world,” he says. “It was not an easy decision to make. Certainly, a bittersweet one. However, that being said, I was really excited about the opportunity to work with Metallica.”

It certainly doesn’t hurt that Dietrich calls himself a lifelong Metallica fan. He first heard Master of Puppets in the 7th grade and was pretty much hooked on their music ever since.

He takes over for Blackened’s founding master distiller Dave Pickerell, who passed away unexpectedly last fall. “They are big shoes to fill,” says Dietrich. “He was certainly one of the most legendary distillers in modern times.” Pickerell, who helped create the craft-spirits boom, had worked at Maker’s Mark for years before becoming the preeminent consultant to craft distilleries around the country.

He was integral in formulating the concept for Blackened, which is currently a blend of straight ryes and bourbons. The unique—and genius—twist is that soundwaves from the band’s music help with the aging of the whiskey, pushing the spirit into the wood of the barrel. The idea, according to Dietrich, was inspired by the vibrations caused by the huge pipe organ at West Point, where Pickerell was a student and later a professor.

The members of Metallica—lead vocalist and guitarist James Hetfield, lead guitarist Kirk Hammett, bassist Robert Trujillo and drummer Lars Ulrich—create playlists of songs from their catalog that play in the warehouse. (The playlists are available on Spotify and Apple Music.) As a result, Ulrich, who is also the band’s co-founder, says each batch is slightly different, but cautions that you shouldn’t overthink it. “We can’t take it so seriously. The idea of connecting it to the music in an abstract way is supposed to be fun,” he says. “Now, I’m not sure I can tell the difference between the batches, but I’m sure somebody can. But that’s okay also. It’s the same thing as when we play “Enter Sandman.” It’s slightly different in Philly last night than it was in Charlotte on Monday. And it should be because it’s fucking human.”

Ulrich might not be precious about how you drink the whiskey, but he takes the brand quite seriously. Sure, Metallica is popular enough, with an incredibly loyal following, that they could have put their name of any liquor bottle and it would have sold. But they spent several years working on Blackened and wanted to create a quality spirit with talented whiskey makers.

“We wanted it to stand on its own,” says Ulrich. “We didn’t want to call it Master of Puppets Whiskey or some bullshit like that.”

The band also wanted a whiskey that was drinkable. “It’s very assertive, but it’s still very smooth and has a very kind of easy aftertaste,” says Ulrich, who was very concerned with making the whiskey seem modern. “When we started drinking, we would drink beer and maybe drink some cheap wine or whatever. But whiskey drinks, that was kind of a different generation. Then when we came to L.A. and started hanging around some of the L.A. bands, Guns & Roses, it was Jack Daniel’s and all that type of stuff. It felt like the people who were enjoying the whiskey, not just drinking it to get drunk, but enjoying whiskey, that was more of an older generation. One of the things that I really wanted to do with this was try to modernize it a little bit.”

It’s an interesting project for the band, since its other co-founder Hetfield doesn’t drink. “I didn’t know how this would play out,” admitted Ulrich. “James’s interest in the creative part of this, obviously, other than the taste has been way more than I expected. We look at it as another creative outlet. It’s another creative bridge to the fans that are interested.”

Dietrich and Hetfield bonded quickly. “I hit it off with James over motorcycles,” he says. “We’re both gearheads.” Dietrich is being modest, having worked on cars and motorcycles since he was a teenager growing up in rural Colorado. He’s particularly excited about a 1948 dual cab GMC, with barrels on the back, that Hetfield gave the brand.

Right now, Blackened is sourcing the whiskey that Dietrich will blend. When I asked Ulrich if one day Blackened will have a distillery and visitor center, he said, “The one-word answer is yes. The two-word answer is fuck yes.”

That will also allow Dietrich to come up with new products, something that he showed a real interest in and aptitude for at Stranahan’s. Every winter, fans of his limited-edition Snowflake Whiskey would line up days before it went on sale at the distillery, even camping out on the sidewalk in arctic conditions to make sure they got one of the few bottles.

“For me it’s definitely an honor to be able to continue to uphold Pickerell’s legacy and maintain the quality and consistency of Blackened, as well as creating new and unusual expressions,” says Dietrich. Ulrich is also open to expanding their portfolio; a tequila or a gin may be in the works one day.

Just as Dietrich was able to help establish the American single malt category with Stranahan’s, he hopes to do the same for the profile of blends. “I think historically blends have had a bad rap in the United States, but if you look elsewhere, if you look at Scotland, Japan, blends are world class,” he says. “I feel like we’re bringing back that reputation.”