Remember Bud Ice, that line of Budweiser whose label came adorned with a zippy typeface that seemed to say I’m chill without outright saying it? Most of the ’90s teenagers who made Bud Ice and its brethren (Busch Ice, Keystone Ice, Natural Ice) house party companions probably never knew why the word “ice” even appeared on the label. But that moniker denoted a method of freezing and concentrating the beer, a process known as icing (or eising, in German), to increase flavor.

Dedicated beer nerds might be familiar with German eisbock, a malty doppelbock that has historically used icing. While its origin stories vary, the accepted narrative involves a brewer’s apprentice accidentally leaving a barrel of doppelbock outside overnight and finding a deliciously freeze-concentrated beer the next morning. But since that fateful discovery more than a century ago, outside of the eisbock—itself a rarity—and those ’90s macro ice beers, which adopted the technique as a fast track to flavor, few beers have been produced using the iced method. That is, until brewers Brandon Capps and Phil Joyce recently revived it.

“I was inspired by ice wine, cordials … port wine and specifically Schramm’s Mead,” explains Capps of his Five for Freezing, an iced imperial stout. “Ice wines in particular use a process that is inverted from that of iced beer making, allowing whole grapes to freeze and concentrate flavors before making the wine,” adds Capps, founder of Arvada, Colorado’s New Image Brewing. The base stout that becomes Five for Freezing begins under 13 percent ABV before laying to rest in local Bear Creek bourbon barrels for 18 months. Capps then uses his custom-built “freeze skid,” a steel tank with a dedicated chilling system that allows the rig to reach subzero temperatures, to concentrate the beer to 16.48 percent ABV.

“I really want people to treat this beer differently,” explains Capps, who spent two years tinkering with the freeze skid to yield the desired result: a beer that takes the big flavors of a barrel-aged stout and concentrates them, boosting the flavors of maple syrup, cacao, coconut, marshmallow and oak. It’s thick without being syrupy, rich without being cloying. The beer is served still, so that, in a testament to its inspiration, it drinks more like a port wine or cordial.

In Denver, only 10 minutes east of New Image, lies Amalgam, a membership-only brewery whose taproom is open once a month. Like Capps, owner Joyce and his partner Eric Schmidt have been exploring icing, albeit with a different beer as the base. Their Balaton Reduction, a limited batch of 240 bottles, begins as a wine barrel–aged cherry golden sour, which is freeze-concentrated to 10 percent ABV.

“We really wanted to create a product that was as rich and robust as the Balaton cherries were whole, before they were fermented,” explains Joyce. “Cherries not only have flavor and color, but skin tannin, nuttiness from the pit, sweetness and acidity,” he says. By freeze-concentrating the liquid, however, brewers lost some of that inherent acidity. They were able to recapture it by blending a small portion of un-iced cherry beer to achieve their original vision for Balaton Reduction.

Both New Image and Amalgam see more ice beers in their future, in a range of styles. Joyce, for example, is planning to create a raspberry version of Reduction, while Capps hopes to use the technique to explore liqueur-inspired products such as Chartreuse- and fernet-flavored beer. “We’re really enhancing the subjective experience of the consumer,” explains Capps. “This isn’t just about putting liquid in a bottle; we’re building a story and a context that people get to be a part of.”