BANGOR — Beer is booming in Bangor, prompting a local brewery to plan another expansion even before it completes one that’s already underway.

Geaghan Brothers Brewing Co. will purchase a three-quarters of an acre plot from the city for $55,000. Bangor City Councilors enthusiastically approved the deal Monday night, congratulating the Geaghans even before the vote was taken.

The expansion into what the city has called the “Roundhouse Lot,” which is bordered by the railroad tracks, I-395 offramp, and Geaghan’s, will give the business space to build a roughly $1.5 million, 3,000-square-foot addition to the brewery, the owners said.

The 37-year-old, family-owned restaurant and pub located at 570 Main St., which added a brewery in late 2011, already is in the midst of an expansion that will double its current brewery space, providing more room for storage, an automated keg washer that will drastically reduce cleanup time, refrigeration and more.

“Our goal with this first expansion is to have more styles available more often,” said Peter Geaghan, who runs the business alongside several family members. The brewery has produced about 15 different beers so far, but only has room to carry six or seven of those in stock at any given time.

Geaghan’s beer, which is only available at the Bangor pub and is produced in a tightly-packed brewery attached to the restaurant, has been catching on in the Queen City, according to Andy Geaghan, manager of the pub and nephew to Peter.

“We’ve been doing just crazy numbers for the equipment and size building we have,” Andy Geaghan said. The brewery, with five fermenters holding a different batch every 16 days or so, is pumping out enough product to supply the restaurant and fill patrons’ growlers. Each batch can fill about 10 kegs. Andy Geaghan said the small expansion that’s under construction right now will give brewers “breathing room,” while the larger future expansion will help Geaghan’s meet a growing thirst for beer in Bangor.

Food still makes up about 75 percent of Geaghan’s sales, according to Peter Geaghan. Beer contributes about 15 percent, with the remainder brought in through merchandise and growler sales.

Geaghan’s has been approached by groups ranging from the American Folk Festival and Cross Insurance Center to restaurants and wedding parties asking if the brewery could supply them with beer for events, according to Peter Geaghan.

So far, the Geaghans have had to say “no” because all their production has to go toward meeting the needs of customers at the pub.

“We’ll never be able to supply that demand in the facility we have now,” Peter Geaghan said.

Now that Geaghan’s has the land it needs, owners and brewers will begin ironing out exactly what equipment will be needed to best use the new space, according to Andy Geaghan. They haven’t set a timetable for when construction on that facility might begin.

The land acquisition also will ease a persistent pain for Geaghan’s — parking. Anyone visiting the restaurant on a Friday or Saturday knows it can be a challenge to find a spot, and some prospective customers turn around when they see there’s no nearby parking available, even though there might be room in the restaurant, Peter Geaghan said.

The restaurant shares parking spaces with the attached Fireside Inn & Suites. Both businesses expect to see an influx of customers after the Cross Insurance Center opens later this fall across the street.

As part of the expansion, Geaghan’s will level out a portion of the Roundhouse Lot to build a parking lot extension. The Geaghans hope the lot will be completed by the end of October, providing about 60 more spaces.

City officials say there will still be room in the Roundhouse Lot if a hotel developer or another entity expressed interest in the site.

Andy Geaghan said the brewery will be careful to not grow too fast and that it likely will focus on ensuring its pub patrons have the beer they want. After the expansion, the Geaghans hope to be able to produce enough to say “yes” to Bangor restaurants and events organizers who want to serve Geaghan’s beer. Geaghan’s plans to stay away from larger-scale distribution, at least for the foreseeable future.

“The goal for us is to grow in a way that we never lose our heart as Bangor’s beer brand,” Andy Geaghan said.