Occidental home brewer Michael Kelly and local beer brewer Bear Republic won top honors this weekend at the Great American Beer Festival in Denver, Colo., the world’s largest commercial beer competition.

Kelly and the Cloverdale-based brewer won a gold medal in the festival’s Pro-Am competition, which pairs amateur brewers with professional brewers.

For the competition, Bear Republic chose earlier this year Kelly’s Bonnie Prince Charlie’s Scottish 80 Shilling, a Scottish style ale that Kelly described as a “refreshing diversion from the big high-alcohol hoppy beers.”

Pro-Am entries must be scaled-up versions of the amateur’s home-brew recipe. That means both Kelly and Bear Republic had to figure out how to produce up to 15 barrels of the beer, a process that does not abide by a “one-to-one” increase in ingredients, Kelly said.

Kelly said the recipe was inspired by the late Greg Noonan, who was head brewer at Vermont Brewing Co. and authored a book called “Scotch Ale.”

Kelly said his recipe has already garnered several awards, including honors at last year’s Sonoma Community Center’s third annual Beervana festival and fundraiser. That competition is sanctioned by the American Homebrewers Association, and such recognition is one of the requirements of the Pro-Am competition.

“We already had an award-winning beer in front of us,” said Clay Grosskopf, marketing manager for Bear Republic.

“We chose this beer because it was one of the best beers that we tasted and we wanted to work with local home brewer Michael Kelly,” Grosskopf said.

Bear Republic’s Double Aught pilsner also won a bronze medal in the festival’s Bohemian Style Pilsner category. Prior to this weekend’s competition, Bear Republic has won 19 awards at the Denver beer festival.

This is the first time Bear Republic won the Pro-Am category, Grosskopf said.

Russian River Brewing Co. also took home two medals, bringing the total for Sonoma County brewers to four, Grosskopf said. Russian River’s Pliny the Elder earned a bronze and its STS Pils a silver.

Kelly said the win was a “dream come true,” and he thanked Bear Republic for all of its support.

He said the Bear Republic version “is every bit as good as my home-brew version.”

The award-winning batch of Kelly’s Scottish ale is currently on tap at Bear Republic’s Healdsburg pub.

“They’ve had it on tap at the pub since Aug. 25,” he said.

Reach Staff Writer Martin Espinoza at 521-5213 or martin.espinoza @pressdemocrat.com.