Sebago Brewing is releasing limited four-packs of its Barleywine, with each beer made in a different year, starting in 2019. Photo courtesy of Sebago Brewing

Barrel-aging beer is always lengthy process, but two new releases from Maine breweries represent even more than the usual time and effort, and both pack a significant punch.

In celebration of its 25th anniversary in April, Sebago Brewing is releasing four-packs of its Barleywine, with each beer brewed in a different year between 2019 and 2022. Called a vertical release, the limited-edition four-packs will allow the 250 beer aficionados who nab them to taste how the wine-strength ale, which ranges from 9-14% ABV, changes over time.

Meanwhile, Belleflower Brewing, which just marked its second anniversary on Sunday, recently released a double barrel-aged Baltic porter with coffee – the result of a process that started not long after the East Bayside brewery opened.

A collaboration with J. Wakefield Brewing of Miami, Florida, the 10% ABV beer – called Revival of Consciousness – started aging in Old Elk Wheated Bourbon casks 18 months ago. After a year, it had developed charred oak and vanilla aromas from the wood, but the brewers felt that the spirit character could be further enhanced, so it was transferred into fresh rye whiskey barrels for another six months, which gave it flavors of toasted oak and baking spices, according to Belleflower co-owner Zach Page.

The beer was then blended with freshly brewed Baltic porter, a style similar to an imperial stout but with lighter roast flavor, to “reach the perfect balance of dark malt flavors and barrel character,” Page said. Next, it was aged for a week on top of coffee beans from Time & Tide in Biddeford, which he said added a “beautiful, fruit-forward cold brew quality.”

Zach Page and Nick Bonadies, co-owners of Belleflower Brewing, which recently released a double barrel-aged Baltic porter that’s been in the works nearly as long as the two-year-old brewery as been open. Photo by Caylin Henderson

Sebago’s Barleywine spends a year aging among 16 fresh bourbon barrels that come from a variety of distilleries through Maine-based barrel procurer River Drive Cooperage & Millwork. Fresh barrels impart more bourbon aroma and flavor into the beer aged in them, said Sebago’s director of brewery operations, Peter Dahlen, and the charred wood adds flavors of toasted oak, vanilla, coconut or caramel. These qualities vary widely, even among barrels from the same distiller, he said, giving the aged beer a lot of nuance once it’s all blended together.

Barrel-aging beer is not only time-intensive but also challenging. Page said that every time a beer is moved between vessels, there is a risk of introducing oxygen, resulting in stale flavors, as well as a risk of infection from wild yeast and bacteria. That makes it important to regularly taste and evaluate the beer to monitor the development and ensure that it’s packaged at its prime.

Dahlen added that the condition of the barrel also plays an important part in protecting the beer from too much oxidation. The first thing the team at Sebago does is check the barrel to make sure it doesn’t leak and can still hold liquid. The less fresh and the drier the barrel, the more air it will allow in, and the more liquid it will allow out.

Next, Sebago uses carbon dioxide or nitrogen to purge the barrel of oxygen before adding the beer. Some amount of oxygen always gets into the beer, Dahlen said, and just the right amount can intensify sherry and coconut flavors in the Barleywine without bringing on any detrimental flavors.

I asked Dahlen and Page what else I should look for when tasting their new barrel-aged beers. Dahlen said, for a vertical tasting of Sebago’s Barleywine, to pay attention to how age mellows some of the sharper characteristics and bolsters fig, date and sherry aromas and flavors. With Revival of Consciousness, Page said to look for roast flavor and restrained fermentation character from the use of lager yeast for fermentation and the cold-conditioning of the beer.

Caitlin Enz is a Certified Cicerone® who lives in Portland. Follow her on Instagram at @hops_and_brains.