Police are looking for thieves who stole a lorry containing 15,000 pints of real ale, from a haulier's yard in Lincoln.
The beer was in 18-gallon barrels which brewing industry experts believe will be melted down and sold for scrap.
The lorry, which was due to transport the real ale to London for the Great British Beer Festival, was stolen in the early hours of 4 August.
Replacement beers were found and sent to the festival.
James Daley from the Campaign for Real Ale (CAMRA) said he did not know how the thieves would get rid of the haul apart from trying to sell it to pub landlords.
"I don't know if there are some discerning thieves out there who actually like real ale and have stolen it for their own purposes but 15,000 pints is going to take a few weeks for them to drink," he said.
Tony Eastwood, managing director of wholesale company Small Beer from whose premises the lorry was stolen, said the firm had been supplying the Great British Beer Festival for 20 years and had this year received its largest ever order.
He added: "There's a growing concern in the brewery industry about casks being melted down and sold for their scrap metal value which can be as much as £30 a cask."