PORTLAND, Maine -- The state of Maine has banned a beer, not because of what's inside but because of what on the outside.

The state said that the label for "Santa's Butt Winter Porter" is "undignified and improper" and may attract children. The label shows Santa's large behind, fully clothed, sitting on a beer barrel.

The beer's name has a double meaning by referring to Santa's rear end and to the "butt" of beer, a term that designates a 126-gallon barrel.

Maine civil liberty groups are taking the case to court. They argue that any artwork, even those on beer bottles is protected by the First Amendment.

"A lot of people think that the first amendment is something abstract, a philosophical idea, but it's really not. It's about the books we read, the movies we see, and the beer we drink," said Zachary Heiden with the Maine Civil Liberties Union.

"I was really surprised that Maine would be the place that would show this kind of odd 1950s-style prudishness," said Daniel Shelton, with the Shelton Brothers microbrew in Sheltertown, Mass.

The microbrewery said it already sells alcohol products that may be considered equally offensive such as wines with topless women on the label.

By law, the liquor licensing division of the Department of Public Safety reviews between 10,000 and 12,000 applications a year for beer and wine labels. The agency typically denies about a dozen a year because they contain inappropriate language or nudity, or might appeal to children, said Maine State Police Lt. Patrick Fleming.

"Basically, the standard we use is what are people going to see walking up and down a store aisle," he said. "We stand by our decision and at some point it'll go through the court system and somebody will make the decision on whether we are right or wrong."

The episode is reminiscent of last year when Connecticut told Shelton Brothers it had problems with its Seriously Bad Elf ale.

"Last year it was elves. This year it's Santa. Maybe next year it'll be reindeer," said Shelton.