One of the beer ads boasts naked people, but they've stripped down to save the Poudre River, not because they're fixing to mud wrestle.

Print ads from New Belgium Brewing Co. focus on the brewer's sustainable philosophies and environmental concerns, a significant departure from the boobs, rubes and flatulence jokes that have often defined traditional beer commercials.

"I think we started with that back with our TV ads (two years ago)," said Greg Owsley, the Fort Collins-based brewer's chief branding officer. "We wanted to stand out from typical beer ads."

Still, creators at Denver's Cultivator Advertising made sure to keep some whimsy in the new "Follow Your Folly" campaign. It's a tone that carries over to the Web site and videos produced in-house at the Fort Collins company. They are selling beer, after all.

Print pieces appear to be printed on recycled brown paper, with plenty of detail and sepia-toned elements to catch the eye. One carries a message of thanks from brewery founders Kim Jordan and Jeff Lebesch. Another - this one with the naked people - tells of efforts to keep a dam project on the Cache La Poudre River from going ahead.

This summer New Belgium will introduce John, who drives the "wormbulance" and has as his stated mission "to lift the lowly worm up from the dirt and into its rightful claim of eco-superhero."

Each ad introduces consumers to an environment-related project going on in the world. Then they can learn more by logging on to www.followyourfolly.com and viewing related pages and videos. The company expects to continue adding content over time.

"We think we'll be more successful communicating to people this way than saying, 'Here's this beer - drink it'," said Cultivator account manager Matt Neren. "That's not true to New Belgium's values."

Print ads are breaking now in 55 publications, a lineup of diverse regional and national magazines including 5280, Men's Journal and Sierra.

The brewery isn't saying what it expects to spend on the campaign, which will continue over at least the next couple of years. National advertising is rare among craft brewers, which by definition brew fairly small batches and tend to sell all of it close to home.

New Belgium sells its brews in 16 states, all of them west of the Mississippi. Its Fat Tire is consistently the top-selling craft brew in the country, according to research by the Boulder-based Brewers Association.

The brewer's sales grew more than 18 percent last year, Owsley said.

Despite growing national exposure through the new campaign and increased sales outside its home base, the company's particularly happy about its 12 percent sales jump in Colorado last year, he said.

"We're proud of that because it's our home market," he said.

forgrievej@RockyMountainNews.com or 303-954-5191