COHASSET, Mass. » When Rhonda Kallman set out to create a beer that would draw a crowd, she never expected the attention her Moonshot ’69 brew received this month.

The problem is that the light beer, made by Kallman’s company, New Century Brewing, contains caffeine. This month, she and three other manufacturers were told by the federal Food and Drug Administration that they must remove the stimulant from their beverages or stop selling them.

While most of the focus has been on two fruit-flavored, high-alcohol malt energy drinks, Four Loko and Joose, Kallman said her small company, which has suffered years of setbacks, is reeling from the news.

"This is prohibition in 2010," Kallman, 49, said. "It’s devastated the company, and as a U.S. citizen, I’m just flabbergasted."

Kallman, a co-founder of the company that makes Samuel Adams, came up with the idea for a caffeinated beer around 2003, when energy drinks like Red Bull were soaring in popularity. She left Samuel Adams in 2000.

"I was looking at what consumers were drinking, and clearly it was caffeinated — look at Red Bull and Starbucks and even Mountain Dew," Kallman said during an interview at her home overlooking Cohasset Harbor. Her office, a single desk, sits behind a couch in the living room. She is the company’s only employee.

And while everything from water to energy drinks with caffeine were selling briskly, Kallman’s amped-up beer was not. She re-introduced the beer in 2006 with more caffeine — 69 milligrams, about twice that of a can of Pepsi — and a bit more alcohol.

Distribution was small and limited, but Kallman pulled the product from the shelf when she was diagnosed with breast cancer in 2008 and health issues made it difficult to run the company.

It was one of a number of struggles Kallman went through, including a long and costly naming-rights lawsuit against her other beer, Edison Light, which Kallman eventually won.

She put Moonshot back on the market in April 2009, but months later she got her first call from the FDA, which had started looking into caffeinated alcoholic beverages.

Kallman said she complied with various requests but did not expect to receive a letter saying she had to fundamentally change her product or pull it from shelves.

She said her beer, which has an alcohol content of 5 percent, is being unfairly lumped in with high-alcohol, high-caffeine malt energy drinks that bear no resemblance to Moonshot or other beer.

The FDA said the letters were sent because caffeine was put directly in the beverages as a food additive and was not naturally occurring, as it would be in a beer brewed with coffee.

Kallman said the agency should set parameters for alcohol with caffeine, including those from naturally occurring sources.

"Give us a base line," she said. "I’m happy to comply. Regulate, but don’t ban."

Michael Herndon, a spokesman for the agency, said its investigation was continuing "and might lead to action against other, similar products."

But Moonshot ’69 has been controversial within the craft brewing community, said Jay R. Brooks, an independent beer writer who runs the Brookston Beer Bulletin blog.

"Her Moonshot product has taken a lot of shots not just this time, but from some craft beer lovers who don’t like Moonshot for the same reason, because the caffeine is added," Brooks said. "They sort of see it as a stunt beer or novelty beer. She is in kind of a difficult position."

Brooks, who vehemently disagrees with the FDA’s action, said Kallman’s beer became unfairly caught up in the regulations.

"There’s nothing about what she’s doing that makes it similar to Four Loko," Brooks said. "She was the dolphin that got snared in the net."

Kallman has stopped brewing Moonshot for the time being. She was planning to serve it at a recent beer festival, but Massachusetts passed an emergency resolution prohibiting the sale of caffeinated alcohol, and she could not.

So now Kallman has $25,000 worth of inventory she cannot sell. While she is not sure what she will do next, Kallman said she would go down fighting.

"I’m a responsible marketer who has more than 25 years in the business," she said.