(SFGate) - Trademark-infringement lawsuits rarely garner more than a disinterested shrug, but when one of Northern California’s best-known craft brewers sues another over a beer label, furious drinkers take to the tweets.

On Monday, Petaluma’s Lagunitas Brewing Co. filed a lawsuit against Sierra Nevada Brewing in U.S. District Court in San Francisco regarding Sierra Nevada’s newest beer, which had yet to leave the Chico brewery.

Barely a day later, Lagunitas founder Tony Magee announced via a Twitter apology that he was dropping the complaint — prodded, no doubt, by a storm of social media outrage.

At issue: the packaging for Sierra Nevada’s Hop Hunter IPA, originally set to be released Thursday but now postponed by a week or more.

The suit claimed that Hop Hunter’s label copied the distinctive Lagunitas IPA trademark, with its serif font, slimmed-down spacing between the “P” and the “A,” and “slightly aged or weathered look.”

At best, Hop Hunter might look like a collaboration between the two breweries. At worst, well, Lagunitas was seeking a temporary restraining order against the beer’s release, as well as punitive damages.

“If you see someone out there using your mark in a way that’s confusingly similar, it’s incumbent on you to make sure it doesn’t become generic or widely used,” said Brendan Palfreyman, a trademark attorney specializing in craft beer.

A big seller

It’s a valuable trademark, too. Lagunitas has made the IPA — a bitter, extra hoppy beer style that British brewers originally made to ship to India — for almost 20 years. The beer represents 58 percent of the company’s considerable output.

This isn’t the first brew-based lawsuit in the Northern California craft beer scene. Anchor Brewing has sued smaller breweries over using “steam beer,” a historic style that the San Francisco company has trademarked, and Lagunitas itself was once required to change the name of a beer to avoid infringing on another brewery’s trademark.

Nevertheless, Palfreyman, based in Syracuse, N.Y., was quick to recognize the significance of the Lagunitas complaint.

“It is one of the first times that two big craft brewers have been in a lawsuit against each other,” he said. He was among the first to tweet out news of the lawsuit.

Another potential implication: Any brewery printing “IPA” in large, capital letters on its bottles could be targeted next. Considering that IPA — which stands for India Pale Ale — has become the most popular craft beer style in the country, that’s a lot of potential punitive damages.

Lagunitas’ suit seemed to violate the craft beer community’s image of itself as a congenial band of brewers and drinkers. A decade ago, Russian River Brewing and Avery Brewing avoided a similar lawsuit by jointly producing Collaboration, Not Litigation — the beer equivalent of the dance-off in Michael Jackson’s “Beat It” video.

Once word of the suit hit, consumers expressed pub-brawl levels of anger against Lagunitas on Twitter and Reddit and in the comment sections of news sites (which, to be fair, are rarely filled with genteel parlay).

Many of the mob were initially under the impression that Lagunitas was claiming ownership of the acronym IPA. At first, Magee took to Twitter to explain. His feed was then stormed with comments such as, “You’re suing over kerning? The labels look nothing alike and you’ve just done more damage to your brand than SN did.”

That was one of the polite ones.