Spiralling energy costs could push the price of a pint of beer up by more than 50p, experts have said.

Unlike domestic energy users, there is no price cap for industry – leaving businesses at the mercy of the open market.

Fergus Fitzgerald, head of production at Southwold-based brewery Adnams, said all aspects of beer production had been hit by the increase in energy price rises – from the cost of making bottles and cans, to the availability of CO2 used to make some beers fizzy.

"All through the brewing process we're either heating or cooling at some point," Mr Fitzgerald said.

"We are seeing substantial energy costs coming through. And it is a big chunk of our of the cost of making beer and not just for us, but the cost of the things we buy."

Earlier this week, the UK's last fertiliser plant – which produces the CO2 used by breweries as a by-product – halted production after energy costs made production "uneconomical".

Mr Fitzgerald said the brewing industry was still coming to terms with what the closure would mean.

For customers, this could mean the cost of a pint would rocket by more than 50p.

Mr Fitzgerald said: "You might be seeing 50p on a pint, but it will vary dramatically depending on the pub's own energy bill situation."

"We've got to be mindful that we want to make sure beer is still an affordable treat, we don't want to push it into being a luxury. It needs to be something everyone can enjoy," he added.

Smaller breweries are also having to prices up. John Bjornson, owner of Earl Soham Brewery, said he had been forced to put prices up by an average of several pence per pint – but, he said, this translated to an increase of around 20p on the pump price in order to preserve the landlord's profit margin without taking into account the pub's overheads.

Despite being hit by Covid and the costs crisis in such quick succession, Mr Bjornson said: "I've been doing this for nearly 40 years. We've seen tough times and been down to our last farthing several times.

"I've already put the prices up a little, we'll just have to see what the bank statement looks like at the end of the year really."