Bars and bottle shops across the UK have credited a soft drink-inspired sour beer brewed in Edinburgh for helping them to weather a dreaded January sales slump.

The Iron Brew sour beer from Vault City promises the taste of Scotland in a can, with the same orange hue as the fizzy drink it’s modelled on, but infused with an alcoholic tang which forms the base of all of the brewery’s flavoured creations.

Released at the start of each year to coincide with Burns Night, the beer has become something of a phenomenon amongst the county’s craft beer lovers, with close to 25,000 pints sold in over 100 bars during the latest limited edition run.

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Colin Gardner, who opened the Caledonian Craft Beer Merchant shop in Dunfermline in  2019, said: “Though January is traditionally the quietest month of trade for on and off-sales businesses, we can rely on Vault City’s Iron Brew Sour to bring plenty  of people through the door as the first ‘hype’ beer of the year.”

The Herald: Pictured: The Iron Brew sour beer from Vault CityPictured: The Iron Brew sour beer from Vault City (Image: Supplied)

Demand is high south of the border too, with Rosie Fryer, co-founder of  R&G's Beer Vault and R&G's Tap House in Macclesfield adding: “We are constantly asked about when Iron Brew is coming back; it's made a huge impression on our customers.

“When we get a heads up that it's on its way, we know we always have to order double what we did the year before. 

“We held a Scottish Showcase event to highlight the brilliant breweries we love to drink, and Iron Brew was the headliner.”

 So successful was this year’s run, which for the first time included two sister editions of an ‘Iron Brew Float’ and ‘Fiery Ginger’, that Vault City’s sales were boosted by nine per cent in January, making it an ‘outlier in the industry’.

Knowing that tempting customers in with a familiar flavour is a surefire way of opening their eyes to the world of sour beer is Vault City founder Steven Smith-Hay, who left behind his nine-to-five as an IT consultant to pursue a passion for all things fermentation in 2018.

What began as a series of ambitious kitchen experiments to create a fruit-forward brew now sees his team brew 1.4 million litres of sour beer per year from the firm’s 5,000-square-foot production facility in Portobello with plans to upscale even further soon.

“We know products like this, beloved, filled with nostalgia and a bit of novelty, can help bars during those difficult months where people aren’t buying lots of beer,” he said of his Iron Brew.

“Every Scot loves a can of the orange stuff; the bold colour and unique flavour evoke a sense of national pride that’s otherwise only found when talking about Scottish tap water.

“Pubs are such an important part of our culture and it’s incredibly concerning whenever we see one close – that’s something that happens all too often.

“All year round, we work in partnership with pubs to drive footfall and create one-of-a-kind experiences.”

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Of course, it’s not just the Iron Brew beer that has made Vault City one of the top-rated breweries in the UK, as head of marketing Richard Wardrop told the Herald.

The Herald: Pictured: Vault City head of marketing Richard WardropPictured: Vault City head of marketing Richard Wardrop (Image: Supplied)

He said: “We’ve often tried to tie into key calendar dates with releases like the Iron Brew beer or our Love Hearts for Valentine’s Day.

“Obviously we’ve also worked on a core range, and have a significant supermarket presence now, but the bread and butter of Vault City is essentially six new flavours released every month.

“It’s small batch, rotational stuff.”

Watermelon Slices, Raspberry and White Chocolate Swiss Roll or Toasted Coconut and Lemon Drizzle Doughnut are just some of the Wonka-esque combinations that have previously been released by the team.

Wardrop believes that this lighter-hearted approach to craft brewing has helped to make their products more accessible, allowing them in turn to extend their reach.

“Steven really saw an opportunity to appeal to people who are looking for an entry into craft beer rather than looking for more complex flavours you would find in Lambics or Saison beers,” he said.

“What we do seems to resonate with people who wouldn’t typically be beer drinkers.

“I like to joke that my wife, for example, would never order a pint of Tennent’s but she loves our Cloudy Lemonade.

“Our ratio of male to female drinkers is about 60% to 40% which is something that’s very interesting for our brand.”

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When Smith-Hay first launched his business in 2018, his beer of choice was still considered a ‘niche’ product, with many sceptical of a base flavour that has been likened to the punchy hit of sour sweets.

While it has become more popular in the years since, Vault City has recently launched a brewery  tour and ‘sour school’ experience to help educate visitors on ‘how the magic happens’.

Wardrop said: “We’re not Johnnie Walker, but we do get a lot of people making a sort of pilgrimage to the brewery.

“It’s lucky that we’re based in Scotland because it gives us access to so much lovely fresh fruit.

“We work with literally tonnes of purees and juices and our own house culture, like a sourdough starter, which is the same we have propagated and cultivated since 2018.

“That gives us a consistent flavour which we can then keep adding different twists to.

“At the sour school, we give people the chance to make their own concoctions which is a really fun way to help them understand how the secondary fermentation stage works.”

The Herald: Pictured: Vault City has developed hundreds of flavour combinations over the yearsPictured: Vault City has developed hundreds of flavour combinations over the years (Image: Supplied)

Tours are keeping the team busy for now, but following a crowdfunder which raised more than £250,000 in just two weeks, the next challenge will be moving to a new ‘forever home’ which is seven times the size of their current unit.

Wardrop said: “Sours are big within craft beer at the moment, but having an edge in the mainstream market has definitely worked for us.

“We now have UK-wide distribution in four or five major supermarkets, which would have been unheard of a few years ago.

“We’ve been totally independent since we started so any growth we’ve had has been real blood, sweat and tears stuff.

“Building a community of people who love those really wacky, sour beers has helped us to do that and all of the support for the crowd funder was just amazing.

“We’re really excited for the future.”

For more information on Vault City, visit their website at vaultcity.co.uk.

The brewery is also preparing to host the Big Swally, a craft beer festival bringing together 20 of the best UK and international breweries at the 02 Academy in Edinburgh on Saturday, October 19.

To book tickets now, click here.