A Northern Ireland man who was a winner of one of Brewdog's "solid gold" beer cans says he feels “let down” after he learned it is only gold-plated brass.
The Scottish firm offered 10 people the chance to find a gold can hidden in a case of its beer.
Some winners questioned the worth after discovering the cans are gold plated, and one has asked the Advertising Standards Authority (ASA) to probe whether any rules were broken.
A company spokesperson has admitted the use of the term "solid gold" was a mistake, but the firm has stood by its £15,000 claim, saying the estimate was made up of more than just the metal used.
Mark Craig, from Lisburn, asked for a valuation after he won his gold can and discovered it was actually made of gold-plated brass.
"If you're told something is worth £15,000, that's what you would hope you had sitting on your mantelpiece. I bought two cases online in my attempt to win,” he told the BBC.
"The past 18 months have been tough for everyone. I myself was made redundant and had plenty of need of extra cash. I wanted to sell the can and contacted Brewdog for any certification they had.”
Mark added: “The certificate they sent said it was gold-plated but they promoted it as solid gold. When I contacted them they told me the 'solid gold' claim was an error.
We’ve hidden 5 Gold Lost Lager cans in 5 cities around the world. Today the hunt begins!— BrewDog (@BrewDog) May 31, 2021
Find the secret location with @what3words from 13:30.
Thurs: Berlin (announced at 6pm)
Fri: Columbus, Ohio
London you’re up first! #LostandFound pic.twitter.com/GiuDc5bjC8
"It's not just me that's been let down. Lots of people have lost out on this. Buying extra beer - and buying it online from them directly handing them a higher share of the profits."
Another winner, sales manager Adam Dean, from Shrewsbury, Shropshire contacted the ASA to investigate the prize claim of £15,000.
"I realised I had won after I treated myself to a can after having mowed the lawn and spotted something glistening away in the case,” he told the BBC.
"It said on the can 'you've won a £15k 24 carat gold Hazy Jane can'. Once I'd got over the shock I wanted to cover it on my house insurance. I got in touch with the can's makers, Thomas Lyte, who told me it was actually brass with a 24 carat gold plating.
"I had it valued by a jewellery expert. He told me it was only worth £500. I'm just totally disappointed and I want it resolved. I legally entered a competition to win a solid gold can but I've not got that. I asked for shares to make it up to £15,000 and Brewdog basically said no, so I called the ASA."
He said the ASA had asked for all the emails he's received from the company and told him it will "assess my concerns".
Addressing Mark’s complaint, Brewdog said in a statement: "We have reached out to Mark privately to apologise for the erroneous use of the phrasing 'solid gold' in some of the communications around the competition.
"Once the error was flagged by our internal teams, we immediately removed or changed all such mentions.”
The company continued: "This error may have informed his complaint regarding the value of the can. Importantly, the phrasing in question was never included in the detailed terms and conditions of the competition, nor in the wording informing the lucky winners of their prize."
The ASA said it was assessing the complaint to establish whether or not it needed to take action.
"A complainant has challenged whether the claim that the prize was solid gold is misleading as they believe it's not made from solid gold and rather brass and gold plating,” said a spokesperson for the watchdog.
"They have also challenged whether another ad is misleading as they understand the can is not worth £15 000."