A new BBC podcast has suggested that BrewDog chief executive James Watt was involved in preliminary discussions about a potential sale of part of the business to Heineken.
The six-part series features claims that Heineken walked away because BrewDog's valuation of the company was "outrageous" and that TSG, the brewery's US private equity partner, believed Watt's valuation of the company was "not realistic".
Leaked emails from 2018 reveal Watt told the global brewing group he was "open to being more pragmatic in our views on independence", having previously criticised craft brewers for selling out to bigger companies.
BrewDog said the BBC's reporting had demonstrated "vindictive scrutiny and malicious criticism" of the beer firm, but it has not directly responded to the new disclosures.
The BBC stated that it understands the Heineken discussions did not progress beyond the preliminary stage.
Since launching in 2007, the Ellon-based brewer's crowdfunding model has seen it raise £100m via around 200,000 'equity punks' minority shareholders.
In January, the BBC's Disclosure programme questioned just how punk the company still was, while also looking into claims of a toxic workplace and inappropriate behaviour by Watt.
He denied behaving inappropriately and apologised to anyone who has felt uncomfortable because of his behaviour. BrewDog has since submitted a complaint about the programme to Ofcom.
Last week, Watt told Insider that BrewDog is still preparing for an initial public offering (IPO), although it is now waiting for better market conditions before listing.
The BBC understands that in late 2018, investment bankers representing BrewDog approached the world's second biggest brewer to discuss an IPO alternative, via selling a stake in the business.
Documents show that Watt met senior Heineken representatives, and later wrote to the then European president Stefan Orlowski.
Watt told him that BrewDog was "open to exploring potential strategic partnerships" if it could be "better for the long-term of our business than an IPO", adding that he was "open to being more pragmatic in our views on independence".
In its documentary, the BBC revealed that Watt had purchased about £500,000 worth of shares in the Dutch beer giant in 2017. He has since said he no longer holds the shares and only bought them to help with negotiations about a potential distribution deal with Heineken, which fell through.
A source close to the discussions in 2018 told the BBC that Heineken walked away before negotiations properly got under way, adding: "It was so outrageous, in his price idea, that we said well this is going nowhere - the guy doesn't know what he's talking about."
Other claims made in the podcast relate to TSG, which bought a 22% stake in the company in 2017 and took two seats on the board.
Documents from late 2018 appear to show that the private equity firm was unhappy with aspects of how the company was being run, with a recent board meeting being a "low point" and was "sloppy, free ranging", with "no discussion on real business topics".
TSG was worried about a shortfall of earnings, while the documents also suggest TSG believed Watt was "spending aggressively" to "create growth stories in order to reach an unattainable valuation" - adding that his valuation goal was "not realistic".
BrewDog recently stated that a manager from Goldman Sachs valued the company at more than £1.8bn.
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