What Happened When a Brewery Fed Its Beer 11 Days of Heavy Metal Music

Bruce Dickinson has to be kicking himself. Four years ago, the Iron Maiden frontman partnered with Robinsons Brewery to release an ale called Trooper, in honor of the heavy metal band's early-80s single. But he really missed an opportunity to call the beer "Number of the Yeast," which would've been a much better name. Fortunately, New Zealand brewers Garage Project have grabbed that devilish pun by both horns and are using it in reference to its Dark Resonance IPA, which came from the craft brewery's 666th batch of beer.

To ensure that Dark Resonance was—as head brewer Pete Gillespie put it—"as dark as the devil himself," the beer was assaulted with non-stop black, death, and doom metal as it fermented. For eleven straight days, a speaker inside the tank blasted the kind of playlist that would cause the Sistine Chapel's paint job to peel, in the hopes that it would affect the beer in the most diabolical way.

Antichrist-approved IPAs aside, Garage Project has made a name for itself as an innovative, if not flat-out eccentric brewery. Some of its previous beers have included volcanic rocks, fermented fish, and hop hash—but they've all worked. Although the Project was just established just over five years ago, it has already been named New Zealand's Brewery of the Year three straight times. MUNCHIES had the chance to speak with Gillespie about Dark Resonance, dank hops, and the appropriate drinking vessel for the blackest of black ales.

MUNCHIES: Congratulations on your 666th brew. How long did it take you to make that much beer?

Pete Gillespie: When we set up the Garage Project here in Wellington, we set up on a really tiny little kit. We were only brewing 50 liters of beer at a time, because it was all we could afford. We started out with something we called the 24/24, which meant that we did a completely brand new beer every week for six months. A lot of them were quite experimental, a little bit out there, and we launched them in tiny batches in a bar in town. It was great fun but kind of terrifying, because every week, we'd go down there with something brand new on offer. And we often had no idea what it tasted like, because the quantity was so small, we couldn't spare much to try. We managed to get a bit of a cult following from that, got some money, and set up a bigger brewery. We've been going for 5 ½ years now and it took us quite a long time to get to 100 [batches of beer], but now we're whizzing along. We're up to 800 now, but 666 seemed like a notable number that should be celebrated.

READ MORE: This Craft Brewery Infuses Its Beer with the Wu-Tang Clan

How do you decide what direction you're going to take each beer?

It's kind of a whim. For this, there has been a lot of scholarly paperwork on the effect of music on yeast. There are vintners who play music constantly to their barrels of wine and hope the yeast is happier and produces a better quality product, which I find fascinating. We decided to pursue the idea of playing music to our yeast. For the first project, Resonance, we got in touch with the New Zealand Symphony Orchestra. Their assistant conductor produced a playlist for us of classical music that we thought would match the various moods of the yeast during fermentation. We also managed to get an underwater speaker from a researcher at one of the universities here. It will only play under liquid; if you try to play it out of liquid, it explodes, which is terrifying.

How did the yeast—and the beer—respond to the Symphony?

It was quite a disastrous project, actually. We managed to destroy three Apple computers and three cameras in the process, mostly because brewing and computer technology seem to not mix. Water and Macs don't like each other very much, but it was a fascinating exercise and the beer we got out of it was really interesting. The yeast fermented far more than it would usually and we thought we got a lot more hop flavour out of the subtle, dry hopping we did of the beer. It fit with the research, that maybe the vibration of the music encourages the yeast to be more active.

And you decided to build on that discovery for Dark Resonance?

Yeah, we wanted to progress the project to see what would happen next. We've got a friend, Jimmy, who's covered from head to toe in demonic tattoos and we share his love of darker music. We got him to prepare a playlist and he arranged 11 days of nonstop dark metal, doom metal, death metal and heavy metal. He arranged it chronologically, with no repeats for those 11 days. That's dedication.

Was the beer itself different than the classical version?

For this, we used a lot of your American hops, which have a dank, kind of weedy quality. We chose the weediest and dankest of the hops, which was designed to be super black and super strong, over 10% alcohol. We brewed the beer, submerged that speaker and played it all this metal.

Could you actually hear the music when it was playing?

I've got to say, it's the most eerie experience having music playing in a giant stainless steel tank. It's 40 hectoliters and it's hard to explain the noise that comes out of it. It would go quiet, and then you'd walk past the tank and suddenly you'd hear this kind of demonic [muffled metal vocal sound] coming out. We've got some real fragile creatures around here, so some of the brewers got to the point where they couldn't cope anymore, because it was all too demonic for them. It was awesome.

And you filmed the process too. What are we seeing in the video clip?
You're seeing the empty tank, then you're seeing the wort. That's the yeast food, the sweet sugars from the malt, with water and hops added. As brewers, we have to look after the yeast. If you don't have happy yeast, you don't have good tasting beer. So you'll see the wort coming up and filling the tank, then there's a little pause—the lag phase—when the yeast is starting to get going. There are these various phases of activity where the yeast forms what's called a barm. The naked eye doesn't see it, but by speeding it up, you see what a dynamic creature yeast is. The yeast then ferments, eating the sugars in the wort and converting them to alcohol and carbon dioxide, which makes the beer fizzy. That huge eruption goes on, it subsides, then there's a moment when it becomes quite dark. That's when we've thrown a load of hops in, which sit on the surface and then fall into the beer. It's essentially done at this point, so you see it disappear out of the tank. I like to think that playing aggressive, fast music encouraged the yeast to ferment in an equally fast and furious way. We'll thank someone either up above or down below that it worked out.

You can raise a glass to the deity of your choice.

[Laughs] You know what's fascinating? The accounts department has to work out how much we charge for one beer. There's a formula: they plug in the case price, the price of the can, all of the raw ingredients, the tax—it's very complex. Tickety-tickety-tickety, they type it in, get a case price and you divide that by 24 cans. They came to me and said "Look at this." Can you guess what the price per can is?

$6.66?

Six dollars and sixty-six cents. Exactly.

There is none more black than this beer.

I shit you not.

Have you tasted it?

Oh yeah. It's deceptively drinkable for 10.5% alcohol. Pitch black, but not overly roasty, which is what we wanted.

How does it taste out of a goat skull?

I think we're going to have to try that, aren't we? The correct drinking vessel is a goat skull with a pentagram carved in its forehead. You're lit only by candles, surrounded by your naked acolytes.

While you're burning the hair of someone who wronged you.

Yes. That's the kind of Friday night I'd enjoy.

This interview has been edited for length and clarity.