In this Aug. 20, 2011 photo, beer taps are shown at Cigar City Brewing Co. in Tampa, Fla. Cigar City uses ingredients such as Spanish cedar, guava, Cuban espresso and citrus woods to craft beers that taste of Tampa?s heritage. (AP Photo/Chris O'Meara)

(Corrects spelling of Brewers Association director in paragraph 8 from Gatz to Gatza)

By Barbara Liston

ORLANDO, Fla., April 3 (Reuters) - Beer fans line up every winter at Intuition Ale Works in north Florida for the annual tapping of Underdark, a world-class dark brew aged for a year in bourbon barrels that sells out quickly even at $15 a bottle.

Ben Davis, who owns the four-year-old local craft brewery in Jacksonville, counts on Underdark's two-day spike in revenue to grow his small business.

But a bill pending in the Florida Senate that would cut into Underdark's profit has craft beer-makers crying foul.

The law would force craft brewers to sell their bottled and canned beer directly to a distributor. If they want to sell it in their own tap rooms, they would then have to buy it back at what is typically a 30-40 percent mark-up without the bottles or cans ever leaving the brewery, according to Joshua Aubuchon, a lawyer and lobbyist for the Florida Brewers Guild.

The rule would not apply to draft beer.

"That to me looks like racketeering," Aubuchon told Reuters.

While other states nurture craft breweries, the smaller craft brewers say politically influential national distributors have drawn a line in the sand in Florida to slow the growing popularity of independents who offer an alternative to the standard American light lager fare.

U.S. craft brew sales grew 18 percent by volume in 2013, while overall beer sales dropped about 2 percent, according to the national Brewers Association, which defines craft breweries as those producing under 6 million barrels annually.

Still, the craft industry remains small, accounting for about 8 percent of all beer sold nationally but as high as 20 percent in craft brew-friendly Oregon and in the double digits in states like Colorado, California and Washington, said Brewers Association director Paul Gatza.

In Florida, where craft brewers say their market share remains under 6 percent and most breweries produce under 3,000 barrels annually, the small beer makers are out-gunned in the legislature, where influential politicians have vowed loyalty to the national distributors.

Mitch Rubin, lobbyist for the distributors' Florida Beer Wholesalers Association, told Reuters their goal is to re-write the state's rules governing the craft brewing industry to create strict lines between manufacturers, distributors and retailers, which he said would preserve competition.

Craft brewers say the distributors' clout has resulted in odd regulation in Florida, including a ban on the use of 64-ounce (half gallon) "growlers," which are reusable jugs that can be filled directly from a beer tap and sealed for sales to-go.

Florida allows the use of quart and gallon growlers, but the 64-ounce size is the most popular in 47 other states where it is legal. Craft brewers are trying for a fourth straight year to overturn the ban.

"It's not going to be that big of a deal (to distributors)," said Joe Redner, owner of Tampa's Cigar City Brewing. "But their response is always to come over the top with a nuclear option."

The result was a Senate bill filed without a named sponsor that permits 64-ounce growlers but forces direct sales of all bottles and cans to a distributor, Aubuchon said.

The bill passed its first committee hurdle last week by 10-0 vote.

By contrast, the Brewers Association counts 37 craft brew-friendly states - Texas and Michigan most recently - that permit beer makers to distribute their own beer under various limitations.

"What it's doing is it's allowing all these new breweries to pop up. We're seeing more than a brewery opening per day," the Association's Gatza said. (Editing by David Adams)