One Saturday afternoon, Michael Anderson and Brian Purcell were kneeling in front of a copper pot still, watching a steady stream of spirits flow into a bucket.

“Wow, that’s interesting,” Purcell said, sniffing and sipping the clear liquid from a tasting glass.

“You can really get the spices, even after distilling,” Anderson said. “It’s almost like a gin.”

Anderson, the co-founder and president of Independent Distilling, and Purcell, the founder and president of Three Taverns Brewery, run their businesses out of neighboring warehouse spaces along East College Avenue in Decatur.

But they recently bridged the few hundred yards between the distillery and the brewery for an experiment that is turning 32 quarter-barrel kegs, or about 240 gallons of beer, into a single, one-of-a-kind barrel of whiskey.

The beer, Feest Noel, is a strong, Belgian-style quad spiced with cardamom, allspice and cloves that Three Taverns made for the holiday season, but didn’t quite sell through.

“We were sitting on some extra kegs,” Purcell said. “We wondered if these guys would be interested in distilling Feest Noel into whiskey, and they jumped on the idea.”

“‘I’d been wanting to distill some beer,” Anderson said. “This would not have been my first choice because of the spices. That’s a wild card. But when Brian asked, I was ready to try it.”

It turns out, beer and whiskey have been boon companions for a very long time. Many styles of whiskey begin as a mixture of malted barley, water and yeast, called “distiller’s beer” or “wash.” Most beer starts the same way, except it’s flavored with hops, which impart bright and bitter aromas and flavors.

More than that, American craft brewing and distilling have a history that goes back to San Francisco’s pioneering Anchor Brewing Co., which began its spirits program in 1993. Since then, Anchor Distilling has produced award-winning Old Potrero Whiskey, Junipero Gin, and host of other spirits, alongside famous beers, such as Anchor Steam.

Independent Distilling came to the Atlanta market in July 2014 with a Georgia corn whiskey called Hellbender. In December, Independent, a white rum made with premium grade molasses followed.

Anderson compares his style of creative, small batch distilling to craft brewing. “Before craft beer, everything tasted the same, and it was mostly sub-par, American-style lager,” he said.

“Then people realized what beer could taste like, and that there were all these different styles. With distilling, there’s no lack of quality. We have to bring something new to the table. I love the idea of using local grain and other ingredients to make something local and distinctive.”

“It’s all pretty exciting because craft distilleries are growing along with craft breweries,” Purcell said. “To have a distillery across the parking lot, where I literally brought the kegs over on a forklift, was pretty cool. The collaborative effort is the most fun — to know that we’re making beer over there and it’s about to be turned into something completely different over here.”

The grand plan is to release the barrel-aged, whiskey version of Feest Noel around Christmas 2015, at the same time the next batch of Feest Noel beer is released.

“How many opportunities do you get to drink a beer right next to the whiskey that was made from that beer?” Anderson wondered. “That should be a pretty unique experience.”

But Purcell had another idea to take the beer and whiskey collaboration one more step. “What I’m thinking is that once this whiskey is finished and released later this year, we’ll take that barrel and age Feet Noel in it for release next year,” he said. “How crazy is that?”

“That will be crazy,” Anderson agreed. “This is the kind of thing that fires me up.”