To Brother Donald Paul of the Franciscan Brothers of St. Elizabeth of Hungary, the difference between baking bread and brewing beer is only in the details.

Combine grain, yeast and water in one way, and you get bread, like the enormous, fragrant loaves Brother Don bakes and he and his fellow brothers Kenneth and Stephan sell at the Friar’s Bakehouse, their bakery and lunch spot on Central Street in downtown Bangor.

Combine those same ingredients in another way, and you get beer, like the Whoopie Pie Porter and the St. Francis Brown Ale that Brother Don has spent the past few months brewing at their nano brewery on the grounds of the Bucksport monastery. Those two brews, along with a Monastery Ale, are the three inaugural offerings from Friar’s Brewhouse, the brother’s new line of craft beer that went on sale to the public for the first time on Saturday, Sept. 21, at Bangor Wine & Cheese Company.

“I’ve been brewing beer for about five years, but of course I’ve been working with grain and yeast and water for a very, very long time,” said Brother Don, a trained chef with broad interests in all areas of food and beverage. “You put those three things together in different ways and you get either beer or bread. It was really a pretty natural progression.”

The biggest buzz among the beer lovers and friends of the Friars assembled Saturday was created by the Whoopie Pie Porter, named for Brother Don’s popular whoopie pies at the bakehouse. The Porter — which sold out on Saturday — has a slight hop aroma, but mostly a silky, sweet body, with notes of chocolate and cream, as befits a beer named for a whoopie pie. It tops out at around 7 percent alcohol by volume.

The Brown is more aggressively hoppy, with caramel and malt flavors up front. The Monastery Ale, which has 5 percent alcohol by volume, is a smoother Belgian saison, with floral, spicy notes of coriander and orange complementing the hops. The week after Thanksgiving, the Friars will offer a Christmas ale flavored with cloves and other spices, and at Easter they’ll unveil a German Doppelbock.

At Saturday’s event, the Brothers held a drawing for beer fans to win the chance to purchase the first 10 numbered bottles of beer. At $12 for a corked, hand-numbered by Brother Kenneth, 750-milliliter bottle, it’s not unlike buying a bottle of wine — except it’s beer, of course, and it was made in small batches by Brother Don, in a real Franciscan monastery.

Eric Mihan, owner of Bangor Wine & Cheese Company, said Brother Don approached him earlier this year asking if he would sell the beer at his business. State liquor laws prohibit the friars from selling the beer out of the bakehouse.

And though it may seem strange to see friars dressed in traditional long brown robes brewing and selling beer, it’s actually a large part of their history. Monks were among the first in medieval times to brew beer as a trade, making beer in abbeys and monasteries across Europe. Originally, in the Middle Ages, beer was made in order to preserve water, as regular water was often unsafe to drink and beer has to be boiled. It was also an easy source of calories.

“It’s a great monastic custom. There’s centuries of brewing behind us,” said Brother Don. “And if you drink two liters of nine percent beer, you will have conversations with the saints as well. They’ll show right up in your living room and sit down and chat with you.”

Indeed, some of the world’s most acclaimed and sought-after beer is Trappist beer, made by monks in eight monasteries in Belgium, the Netherlands and Austria, and Abbey beers, made by 18 abbeys in Belgium. Labels like Chimay and Orval are familiar to beer fans worldwide, and both are made by monks. Money from sales goes toward upkeep on the monasteries, and to charity.

Brothers Donald, Kenneth and Stephan are Franciscan Friars — different from monks, in that they aren’t secluded in the monaster but are active in serving their community. Selling their beer will help keep the lights on at the monastery on Orcutt Mountain in Bucksport.

“I can’t deny it. We need to pay our mortgage,” he said. “We built this glorious monastery, but we’ve got bills just like anyone else. Hopefully this will help alleviate some of that.”

In the end, though, for Brother Don it’s all about the gratification, both earthly and spiritual, that comes with making things that taste delicious.

“The even more real truth beyond that is that I love brewing beer. I love doing it. It’s fun. Every batch is an act of faith, because you never know what it’s going to taste like until you crack the bottle open. It really is exceedingly gratifying,” he said. “Brewing beer is like baking, and baking is unlike any culinary art. Your formula’s got to be right. It’s always interesting.”

Friar’s Brewhouse beer is sold at Bangor Wine & Cheese Company on Hammond Street in downtown Bangor. For more information, like Friar’s Brewhouse or Friar’s Bakehouse on Facebook.