As Big Beer buys more craft breweries, it’s gotten harder to tell who the true independent brewers are. Now a new industry effort hopes to clear up the confusion by declaring ownership right on the bottle.

More than 800 breweries – including Sam Adams, Sierra Nevada and New Belgium – will soon begin printing seals on their beers that identify them as “Certified Independent Craft.” The initiative, spearheaded by the trade group for independent craft brewers, is intended to differentiate “true” craft beers from those made by the likes of MillerCoors, Anheuser-Busch and Heineken.

To qualify to use the seal, breweries cannot be more than 25 percent owned or controlled by any alcohol company that’s not itself a craft brewer. Its annual production also can’t exceed 6 million barrels.

The growth of the craft beer segment, once in the double digits, has slowed dramatically since those multinationals entered the fray: from 18 percent in 2013 to 8 percent three years later. Some believe they could stem some of that decline if consumers realized some “crafty”-looking beers weren’t actually made by independent brewers.

A bartender pours a beer at The Sovereign in Washington. Dixie D. Vereen for The Washington Post

“We’ve been hearing from our members for almost two years that there is a lot of confusion in the marketplace, fueled by the Big Beer acquisitions,” said Bob Pease, chief executive of the Brewers Association, which represents the independents. “This is a way to give beer drinkers more transparency and more information.”

Small breweries have grown increasingly anxious about Big Beer’s incursion on their limited turf. Five international conglomerates – Anheuser-Busch InBev, MillerCoors, Constellation/Crown Imports, Heineken and Pabst – already control more than 80 percent of the U.S. beer market, according to the National Beer Wholesalers Association.

Conglomerates and craft brewers “have completely different business dynamics,” said Sam Calagione, founder of Delaware-based Dogfish Head. “They don’t have the challenges of access to distribution, capital and raw ingredients that we have. It’s not a level playing field, and that’s capitalism – but to pretend they’re the same type of business, when they’re actually brewed by a multinational conglomerate? It’s not apples to apples.”

Since 2011, 16 independent craft breweries – of the more than 5,000 in the U.S. – have been acquired by Big Beer.

“If I walk into a farmers market, I assume the produce was grown by an independent, local farmer,” said Daniel Kleban, co-founder and brewer at Portland’s Maine Beer Co. “If I found out that stuff actually came from Dole, I’d be upset, personally.”

Big brewers have, for their part, downplayed these concerns. Jim McGreevey, president of the Beer Institute, which represents large companies, said the complaints of indie brewers disguise the fact that the segment’s generally doing well.

Ultimately, craft brewers say, they just want the realities of the market to be clearer: that way, when consumers reach for a six-pack or order at a bar, they know whether they’re really drinking independently brewed beer.

Calagione, the founder of Dogfish Head, admits many drinkers won’t care. But he suspects some passionate minority will – and in an increasingly competitive industry, that could make all the difference.

“People are already seeking out fair-trade coffee and organic vegetables,” he said. Now he and other brewers hope that “Certified Independent” craft beer will be next.