NEW YORK >> The integrity of a cherished Brooklyn-based brand of craft chocolate bar has been called into question after a food blogger published a four-part series of blog posts this month that accused the two brothers who founded it of faking everything from how they learned to grind their cacao beans to the ingredients in their candy and even their beards.

The accusations published on the website Dallasfood.org elevated what had been a long-whispered rumor in the fine chocolate world about Rick and Michael Mast, the two brothers with trendy lumberjack beards and a charming origin story behind Mast Brothers Chocolate in Williamsburg, and it quickly spread to those whom cacao bean varietals and cocoa percentages mean little.

The allegations have drawn comparisons to Ponzi schemers and on social media to Martin Shrekli, the former pharmaceutical company executive who steeply raised prices on some drugs and has been charged with securities fraud. It has thrown into question not just the provenance of a chocolate bar, but the predilection for such goods, with perhaps larger implications for the picked-by-hand, farm-to-apartment movement, underscoring the fact that claims of homespun authenticity are not regulated, or often verified.

“The Masts did not become pariahs in the fine chocolate world because of their beards, publicity or product mediocrity,” the blogger, Scott Craig, wrote in the series, “What Lies Beyond the Beards.” “It was because of their lies.”

In thousands of words, which compared the Masts to Milli Vanilli, the 1990s R&B group caught lip syncing, Craig voiced skepticism about their skill and their beards, and offered a theory: that early in their career — before their three shops, celebrated chocolate wrapper designer and finding favor with the French Laundry chef Thomas Keller — when making chocolate early on and in their own apartment, it could not possibly have been from scratch.

In an interview on Sunday, Rick Mast, who with his brother began making chocolate in a Brooklyn apartment in 2006, said the allegations were untrue — for the most part. But on the claim that the Masts were “remelters” at the start, Mast confirmed the brothers did use industrial chocolate, what is known as couverture, in some of their early creations, before settling on the bean-to-bar process for which they are now known.

“It was such a fun experimental year,” Mast said, adding that the brothers were transparent “to anyone that asked.”

Craig, who lives in Dallas, said in an interview that the admission, following his articles, was a stark departure from how the brothers had publicly represented their product. Their brand is “one of authenticity, one of care, obsession, commitment integrity, transparency, all of that,” Craig said, adding, “This was all a facade.”

That the Masts say they no longer remelt does not matter, he said. He compared the chocolate makers to Lance Armstrong. Had the cyclist used only performance-enhancing drugs to win some races, it would not have lessened the scandal, he said.

“They have a great story,” said Brady Brelinski, 44, who has reviewed over 1,600 bars on his website, “Flavors of Cacao,” and is a founding member of the Manhattan Chocolate Society, a tasting group. “I’m not convinced that what they built there is on chocolate they made.”

What has taken the controversy beyond the chocolate cognoscenti seems to be the Masts’ Brooklyn-tinged narrative of do-it-yourself chocolate bootstrapping. It is mentioned in their articles and recited by guides during the $10-a-person tours of their Williamsburg shop, where tattooed and mustachioed young men pour silver scoops of beans into grinders. Old pictures of the brothers, then clean-shaven, have been circulating as if to prove inauthenticity.

Over the weekend, Twitter seethed with hipster schadenfreude. “The exposés of the Mast Brothers only make me more self-satisfied about hating their chocolate” a writer named Michelle Dean posted. “The story is a hipster ouroboros.”

Rick Mast said the backlash had come as a surprise. “To be boiled down to how you dress or how you wear your beard, or where you live — I think it’s a distraction,” he said. “Our chocolate is our No. 1 focus.”

On a tour of the main factory in the Brooklyn Navy Yard alongside his brother on Sunday, the Masts stressed their transparency. The smoked glass windows were not to keep people from seeing in, they said, but to prevent sunlight from ruining chocolate. In response to charges by Craig that their output in their early days was thousands of bars a week — far more than an apartment-based operation could have churned out — they emailed The Times a copy of the nascent company’s 2008 tax return, and said they made no profit that year.

In the Williamsburg shop, referred to as a chocolate “Potemkin” factory by Craig (the bulk of the product is made in the Navy Yard factory, but about 1,500 bars a year are made at the North Third Street Shop, the Mast company says), however, some customers were concerned.

“I would be bummed,” said Alison Littman, 43, a designer. “I personally love super pure chocolate and also being vegan I prefer to know what’s going into my food.”

At the Navy Yard factory on Sunday, winnowers growled as beans shuffled through them, crackling as cacao husks sloughed off. Rick Mast stood amid his scuttling employees.

“This,” he said, over the noise, “is not a show.”