Metallica bassist Robert Trujillo has admitted he hadn’t originally believed that the band’s music was capable of changing the flavor of their Blackened whiskey. They previously revealed they’d used a technique they called “Black Noise” to help the liquid interact with the barrels that contained it, before the blend of North American whiskeys is launched later this month at the suggested price of $43.

“I’m always one that has skepticism initially,” Trujillo told Rolling Stone in a new interview. “Then I study whatever it is and check it out. I have to go through a process. I was won over by this process maybe five or so months ago.” He added that he called the technique “the mash pit,” adding: “there’s a molecular structure that is somehow mixed in with the sound and vibration.”

The Black Noise concept was devised by master distiller and chemistry professor Dave Pickerell, who worked with Metallica at their Sweet Amber Distilling Co. premises. Explaining that the aim was to “make the barrels feel happy,” he continued: “If you can cause the interaction between the whiskey and the wood to be enhanced by sonic vibration, you can cause the whiskey to pull extra goodies out of the wood,” he said. “We can show with colorimetric data that we’re impacting the color of the whiskey,” he says. “As soon as we’ve got the patent all cleared up, we’ll publish the scientific data on it.”

Drummer Lars Ulrich said the aim of making whiskey was to create a closer bond with their fanbase. “We didn’t want to just get in the business with somebody who had made whiskey and slap a Metallica label on it,” he explained. “We felt it was important to be able to look our fans in the eyes and go, ‘This is something that we started from the beginning and it’s something that has at least, for better or worse, a Metallica touch to it.'”

He added that they aimed to dispel the idea that whiskey was an “old man’s drink,” recalling, “It felt like it belonged to a different generation when I was really young. I would like to think that Blackened, if anybody who’s 21, 22, would feel was something they could embrace.”