IT could add up to the mother of all hangovers for hipsters. A shortage of hops for brewing, combined with a boom in traditional ales, is leaving Scottish craft brewers struggling to cope with demand for some of their most popular beers.

Recent poor hops harvests across the globe - combined with a boom in microbreweries - has left producers scrabbling for supplies of varieties such as Simcoe, Citra and Amarillo, used for adding flavour to ales.

Some brewers have even had to halt production of their most popular ales while waiting for fresh supplies from the next harvest.

Top Out Brewery in Edinburgh brewed the last batch of its bestselling IPA The Cone last summer after it ran out of Simcoe hops.

Michael Hopert, co-founder and head brewer at Top Out, said they were now waiting for supplies from the US in autumn to enable production to resume.

He said: “The Cone was our bestselling beer and it was very highly regarded. But I am probably going to have to wait until January next year before I can make it again.

“It is very frustrating. When we told people we were going to brew our last batch it was all pre-sold before we had even bottled it.”

Hopert said they had since launched a new beer made from New Zealand hops and a new pale ale made with a single hop variety.

He added: “Less supply combined with increased demand has led to these shortages. It is not a new phenomenon, it has happened before, but I think it is pretty bad this time round.”

Aidan Canavan, who founded the Bute Brew Company on the island of Bute two years ago, said the hops shortage has meant he has been unable to brew any more of his bestseller, Scalpsie Blonde, and supplies had dwindled to just half a pallet of bottles.

He said: “Microbreweries are opening up everywhere and the one thing they all need is hops – it is not just in Britain, it is globally.”

Canavan said he was ordering more supplies of hops for 2017 and hoped to be able to resume production of Scalpsie Blonde next year.

But he pointed out the unreliability of the situation also meant there was more need to be creative and experiment with other flavours, such as a new blonde beer he is currently trialling.

“You make a beer and everyone loves it and it has taken you six months to create that beer – then you find out you can’t get the hops for it,” he said.

“So you have to go back to scratch and create new beers. But it makes you a better brewer as it puts you outside your comfort zone.”

Fiona MacEachern, owner and director of Loch Lomond Brewery, said they were trying to secure extra supplies of hops to meet the demand for their “Southern Summit” beer, which was named the best cask beer in the UK at the Society of Independent Brewers' (SIBA) National Beer Awards 2016.

She said they may have to slow down production of this beer at some point this year, but they were doing everything possible to prevent that from happening.

She said: “We just don’t have enough hops for the beer we want to make. It is catastrophic for us, as we are in such a delightful position to be holding that title.

“There are lots of different people we are speaking to and trying to get more supplies of hop especially of the Citra hop, which is our favourite.”

According to the most recent figures from the Campaign for Real Ale, there were 93 breweries in Scotland in 2015 – an increase of 20 from the previous year.

Will Rogers, sales manager at UK hop merchant Charles Faram, said while worldwide beer sales were not growing that quickly, craft beers were taking an increasing share of the market from big international breweries.

“In the UK, for instance, if the big guys lose a 1 per cent share there is probably room for 100 microbreweries to have a reasonable stab at it,” he said.

“On average a microbrewer will use four to five times as many hops per pint of beer brewed compared with a macrobrewery.

“Globally there isn’t a hops shortage, but there is a shortage of the most popular ones people want to brew with.”