On a warm, windy 60-degree afternoon in early February, Freddy Bensch was basking on the new rooftop deck at Sweetwater Brewing dressed in his executive uniform — an open-collared short-sleeved shirt, shorts and flip-flops.

“What a day,” Bensch said, taking a sip of his beer and gazing toward the Midtown skyline. “It’s fantastic, really.”

The 40-year-old Sweetwater owner/president and self-styled Big Kahuna may look and talk like a veteran surfer. But Bensch just landed on the 2012 Georgia Trend list of the 100 Most Influential Georgians, alongside the likes of Governor Nathan Deal, U.S. Senator Saxby Chambliss and Atlanta Falcons owner Arthur Blank.

“I think that was partly because we are a catalyst for people to become involved in important things like the environment,” said Bensch, who is an avid fly fisherman and outdoorsman. “We can bring those ideas to market.”

Asked about his outfit for the January ceremony at the Ritz-Carlton Atlanta, Bensch smiled and shook his head.

“I didn’t shave but I put on a jacket,” he said. “Believe me, we were getting a lot of looks when we walked in. It was like, ‘Who is that guy?’ But it turned out to be a lot of fun.”

Speaking of fun, Sweetwater will celebrate its 15th anniversary with a party at the brewery on Feb. 18. Bensch co-founded Sweetwater in 1997 with University of Colorado roommate Kevin McNerney.

Since then, the business has grown by leaps and bounds, joining older, bigger companies such as Sam Adams and Sierra Nevada to rank among the top 30 U.S. craft breweries.

In 2008, McNerney decided to leave the company to spend more time with his family and take a job as brewmaster at Five Seasons in Sandy Springs. Still, Bensch and McNerney remain close friends. In fact, McNerney recently returned to the brewhouse to create an amped-up version of Sweetwater’s original ESB in commemoration of the 15th anniversary.

“There are so many stories, so many years, so many adventures,” Bensch said. “As great as everything else is here, one of the things I’m most proud of is that Kevin and I have been able to maintain our relationship. You build a business with somebody, that’s harder than being married.”

Last year, Sweetwater embarked on an ambitious expansion project that will dramatically increase its brewing capacity from 100,000 barrels a year to 500,000. In the buildup to the expansion, Bensch hired several key people, including brewmaster Mark Medlin and quality assurance manager Paul Chlup.

“We have really smart people here now,” Bensch said, laughing. “When it was just Kevin and I, that was really hard. I think that’s what I exceed in now — bringing in people who know what to do and how to do it.”

But bigger is not necessarily better or even an absolute goal, Bensch said.

“All hype aside, this expansion is three-quarters about increasing the quality of the beer. The extra capacity is great. Right now, we are brewing 24/7 and 365. That’s not how you want to run a beer business. The expansion will allow us to slow down somewhat and ultimately focus on quality.”

Looking back on 15 years of Sweetwater Brewing, Bensch reflected on the company motto, “Don’t Float the Mainstream.”

“To sit up here right now, and to do what we just did with Kevin, it's absolutely amazing,” Bensch said. “I get to wear shorts and flip flops. I get to hang out with great people. The business revolves around beer, and creatively, it’s still wide open.

"We jumped in the water 15 years ago, and we’ve just been swimming along this entire time. It’s been a nice float.”

Sweetwater 15th Anniversary Party, 2-6 p.m. Feb. 18 Open to the public 21 and over. 195 Ottley Drive NE, Atlanta, 404-691-2537, www.sweetwaterbrew.com.