The craft brewing industry often describes itself as a big extended family of small business owners who won’t hesitate to work together, share ingredients or raise a pint to their shared success.

But beer is also big business. And as the field grows more competitive, that business increasingly involves lawyers.

In the latest example, Left Hand Brewing Co. of Longmont is attempting to trademark “Nitro” as it applies to beer, a term the brewery brought to greater prominence by becoming the first, and so far only, U.S. brewer to bottle a beer carbonated primarily with nitrogen.

“Our main push — and I don’t want to get into it any more than this — is that we have a bottle that is pretty unique,” Left Hand president Eric Wallace said. “That is why we are pursuing it.”

The case is unusual because many breweries pour nitro beers on draft, and the stakeholders range from leading American craft brewers to tiny neighborhood breweries and the maker of Budweiser.

The application has drawn the attention of St. Louis-based Anheuser-Busch, which received an extension from the U.S. Patent and Trademark Office to potentially oppose the application. The nation’s largest brewer has until June to decide.

Left Hand says it spent several years and hundreds of thousands of dollars on technology to bottle nitro beers, which are creamier than those carbonated primarily with carbon dioxide.

“Left Hand strongly supports the craft beer industry and our fellow brethren,” Left Hand spokeswoman Emily Armstrong said in an e-mail. “We have made significant investments, in both technology and people, in the innovation of nitrogenated beers and it is in the best interest of our brand and our employees that we take steps to protect these investments and the Nitro name.”

If granted, a trademark would give Left Hand ammunition to send cease-and-desist letters to other breweries arguing that its use elsewhere might cause confusion, said Ross Appel, a Hollywood, Fla., lawyer who has worked on brewery trademark cases.

Trademark holders are required to not just use their marks but police them, and going after some offenders but not others could result in a trademark being rescinded, Appel said.

Left Hand’s Wallace said: “We are not looking to take over the world and prevent people from doing certain things. But there is so much trademark activity going on right now in our business, it’s not even funny.”

Trademark disputes over names of breweries, names of beers and other issues have become common in craft brewing booms. The Boulder-based Brewers Association announced this week that independent craft brewers experienced an 18 percent rise in production volume and posted $14.3 billion in revenue last year.

In the most high-profile local dispute, Massachusetts homebrew shop Strange Brew Beer & Wine Making accused Strange Brewing of Denver of violating its trademark. After a year of bickering, the parties announced they had reached a settlement. The terms have not been disclosed.

The government can reject trademarks that are “merely descriptive,” meaning a term describing “an ingredient, quality, characteristic, function, feature, purpose or use” of the specified goods or services.

Arvada lawyer Michael Drumm, who has represented breweries in trademark cases, said he considers “Nitro” to fit that definition.

Wallace points out a Nitro trademark has been granted for beer before — in fact, Left Hand successfully pressed its Canadian owner to surrender it. But the government is not beholden to previous decisions, Drumm said.

The saga will be closely watched as other breweries work on nitro beers in bottles or cans. Oskar Blues in Longmont and the Utah Brewers Cooperative in Salt Lake City have either announced or hinted at plans for packaged nitro beers.

Terri Vogt, vice president of communications for Anheuser-Busch, said in a statement Wednesday: “As a brewer, we have produced our own nitrogenated beers and, like many other brewers, large and small, we need to maintain the ability to identify them to consumers. We have not formally opposed the trademark application, but the extension lengthens our window to do so.”

Eric Gorski: 303-954-1971, egorski@denverpost.com or twitter.com/egorski