Boise firefighters were called to a report of a fire at the Woodland Empire Ale House on Front Street just before 1 p.m. Monday.
They found the fire in the cockloft, which is between the ceiling and the roof. They attacked from above and below, with the responding ladder companies cutting a hole in the roof, Boise Fire Battalion Chief Aaron Hummel said.
For safety reasons, the fire department had the power to the brewery building shut off.
Firefighters stayed on scene to be sure the fire hadn't traveled quickly inside the walls of the building. Hummel said those inside the building at the time of the fire used a hose to try to slow its spread and that appears to have helped.
Fire trucks parked in front of the brewery at the corner of 11th and Front were causing traffic to back up in the area.
The cause of the fire is under investigation.
In a Facebook message posted Monday afternoon, Woodland Empire staff said the fire wasn't expected to hamper production and that the brewery's tasting room is expected to be open Tuesday.
"We had the misfortune of experiencing a small structural fire today that ate up a bit of roof in our back warehouse," the message states.
"We wish to extend a heartfelt thanks to the fire companies who responded and worked so hard to contain and minimize the damage. We will overcome this hurdle. Thank you all for your support and patience as we rebuild."