Well, I hate to admit it but I am one of the newly converted. I stubbornly refused to appreciate sours. Until last year, when I tried their Chocolate Dipped Strawberries sour at our local craft beer bar (shout out to Bottle & Barrel in Aberystwyth). I am now a major sour fan, and love brewing my own to serve at MASHED Brewhouse in Aberystwyth. And proudly identify as a screaming fanboy of our friends over at Vault City. Needless to say, I played my ‘’I publish a homebrew magazine’ card to score an interview with them.

 If you don’t know much about Vault City, then a) go out and try some of their sours, they will change your life and b) here’s a quick intro to set the scene: based in Edinburgh, Vault City Brewing are Scotland’s largest sour beer producer brewing around 500,000 litres of beer each year. They’ve been around since 2018 and have been knocking people’s socks off with their epic modern fruit-forward sours, crammed with real fruit ingredients. They also make epic stouts, like Unbarreled V3, their 15% imperial stout conditioned on cacao nibs with shavings of deconstructed 14-year-old whisky barrels. Curious? You should be…

What’s the key to making the perfect sour beer?

Vault City: Our Head of Production jokingly said that the first step is accepting that nothing can ever truly be perfect… but quickly followed up to say quality ingredients, and a clear idea of the beer you want to make are both integral.

How do you pair your flavours?

VC: We tend to reference flavour concepts from cocktails, desserts, smoothies and sweets. We also listen to feedback and suggestions from our customers and team. We then do a lot of blending and benchtop trials in order to verify an idea or come up with an entirely new one!

“a general rule would be to make sure that anything with sugars in it goes in early in the fermentation so that the sugars can be fermented”

When is the best time to add adjuncts - whether it’s fruit juice, sweets or cake?

VC: It’ll vary depending on what you intend to get out of the ingredient, but a general rule would be to make sure that anything with sugars in it goes in early in the fermentation so that the sugars can be fermented. Or, alternatively, it would be added in the boil stage to sanitise and/or draw out more flavour, or you can steep dried ingredients like you would a tea.

What was your most surprising pairing? And worst?

VC: Most surprising: Coffee and Pear. Worst: We strive to avoid these! But, we did have a plan for Strawberry & Cucumber sour that just didn’t work out.

Which yeasts do you find work best for sours?

VC: A mix of yeasts, all bringing their attributes to the table in order to achieve something better than the sum of their parts.

To make a sour do you add additional acids etc?

VC: We control pH throughout the process, typically adjusting this before we add the bacteria.

What can Vault City fans look forward to in 2025?

VC: We made a monumental decision to buy a new brewery following a Crowdfunder sale, and are on a 12-month plan to pack up our current rented space and begin building our new site which is roughly 7 times bigger in size.

Once we’re settled in our new site, we’ll have everything under one roof which should help us become a more efficient business. Our growing team will allow us to experiment more with smaller batch releases, while also focusing on growing our existing customer base in the UK and in global export markets. We’re bringing back more DDF stouts in 2025, Stoopid sours and some incredible AF offerings. We’ll be collaborating with Siren again when they return to Edinburgh, and will also be looking at some more international visitors following our collab with Mikerphone this year.

What question do you wish we had actually asked you?

VC: What’s a “drizzleberry”?

Visit: Wee Vault Tasting Room, 

7a West Maitland Street, Edinburgh EH12 5DS 

Read more, buy beers & merch and find stockists: vaultcity.co.uk ■