Arran Dark will now progress to take on other beers in the Great British Beer Festival held in London in 2017.
The Arran Brewery is currently undergoing a major upgrade on the island and has seen new malt silos installed as well a malt mill, bright beer tanks and a bottling line as part of recent expansion plans.
Managing Director Gerald Michaluk said: “I am very proud of our team winning this award, especially when considering the limited capacity for current brewing with all the refurbishment going on.
"They pulled out the stops again. The new brewery will triple our current capacity and means all beers will now be brewed, matured and bottled on the magnificent Isle of Arran their birth place.”
The brewery has invested over £250,000 in the first phase of the upgrade and a further three phases are planned.
The brewery has also introduced cans for the first time on an experimental basis and a new and exciting Certified as Craft Beer range.
Gerald added that there will perhaps be a shortage of Arran beers in the short term as the work continues: “Yes as we have had to close down production during the upgrade and tanks have not been available for use we have had to severely restrict the supply of our beer so it's official you can feel free to panic buy.
"Our normal production will resume in time for the Christmas, I hope.”