A few years ago Evan Parent would frequent his local supermarket or convenience store in San Diego to buy a six-pack of Blue Moon. The witbier’s placement among other craft beers led Parent to believe he was enjoying an artisanal microbrew with a refreshing hint of orange peel. Then, in July 2012, his friends informed him of a fact anyone can confirm with a quick Google search: Blue Moon is not a craft beer; it’s a mass-produced Belgian-style ale made by MillerCoors. It is also true that the name MillerCoors does not appear anywhere on the Blue Moon label. So Parent, angered that he’d been fooled into thinking Blue Moon was a craft beer, decided this past April to do what any red-blooded American might: sue the brewing behemoth for duping him.

Parent’s lawsuit, which at press time was in preliminary filings, has raised eyebrows in the alcohol industry. “I’m a little surprised that he was duped,” says Danielle Teagarden, a lawyer who specializes in the brewing industry. Although Blue Moon’s advertisements tout the witbier as being “artfully crafted,” the term has no legal meaning. Most consumers would recognize it as marketing, Teagarden says.

Yet to many beer enthusiasts, the distinction of being a craft beer matters. Defining a craft beer is the hard part. Ask 10 experts what craft means and you’ll get 10 different answers. There are also no federal regulations when it comes to defining craft beer.

The Brewers Association, a trade group that represents independent brewers, boils it down to three criteria: A craft brewery is one that sells fewer than 6 million barrels of beer a year, uses “traditional or innovative” brewing methods and is no more than 25 percent owned by a non-craft brewer.

The question of ownership has been testing the limits of what counts as “craft” ever since brewing giant Anheuser-Busch bought out popular craft breweries including Goose Island, Blue Point, 10 Barrel and Elysian. Dick Cantwell, co-founder of Elysian Brewing Company, cast the sole dissenting vote when his partners decided to sell the company to Anheuser-Busch. Cantwell, a former member of the Brewers Association, helped create its definition of craft brewer but admits the term is somewhat arbitrary. A few years ago the association raised the craft production cap from 2 million to 6 million barrels, in part to accommodate Boston Beer Company, whose popular Sam Adams brand has given Budweiser and MillerCoors a run for their money. Cantwell says that adding craft brews to its portfolio could help Anheuser-Busch sell more of its mass-market brands by giving the company access to craft-heavy markets such as Portland and Seattle. The concern for people like Cantwell is that these buyouts will make it even harder for craft breweries to compete.

The turf war over craft beer is a foreign concept in Europe, where small breweries dominate the market and consumers are more likely to differentiate among beer styles than the size of the brewer. Belgian Simon Spillane, who represents breweries of all sizes for the trade group Brewers of Europe, believes removing the “craft” imprimatur when a brewery reaches a certain size—or decides to sell out—is unfair. “I think we shouldn’t stifle innovation from large companies or smaller ones,” he says. “It’s a strange way of dividing up the world.” As for Evan Parent’s case against MillerCoors, it’s unlikely to go to trial. If a judge doesn’t dismiss it outright, Parent might expect a modest settlement—perhaps even enough to buy a few six-packs of Miller High Life. After all, it is the champagne of beers.