What is Barrel Aged Beer?

Of all the weird and wonderful beer styles that come through the shutters of Craft Metropolis towers, there’s one that holds more authority and decadence than any other – the barrel-aged beer. But what is it, how is it made and why – despite an exhale-inducing price tag – is it so flipping sought after? Let me take you on a guide through the barrel-aged beast… and shine a light on some of the finest barrel-aged brewing in the craft beer world right now.

What is a barrel-aged beer?

A barrel-aged (BA) beer is quite simply a beer that’s been stored in an old barrel. Typically bourbon, whisk(e)y or wine, but in the crazy world of beer, pretty much any booze-laced old barrel will do – sometimes brewers use port, sherry or even brandy barrels to age their concoctions.

The eventually chosen barrel has of course stored a glorious liquid before, which means its inners have soaked up all the boozy goodness of a previous occupant. By shifting a recently fermented young beer into one of these old barrels and leaving it to ‘rest’ for a while, the process begins to reverse: the boozy flavours remnant in the barrel’s wood slowly seep into the encased beer, and the beer starts to change and evolve. It’s not just the booze in the barrels that starts to ooze into the beer either. The wood also plays a part, lacing the resting beer with notes of oak, cedar, redwood, or indeed whatever it is the barrel is made from. So you have a new beer with the potential to take on flavours from multiple, unique sources. Already you can imagine the myriad possibilities. The beer going in, the age of the barrel, the wood, the previous beverage… the outcomes are, speaking practically, limitless!

How does it work?

When the beer goes into the barrel it will initially take on some of the flavours of the previous liquid. That’s the first stage. Most barrel-aged beers also take on some base flavours from the wood quickly, which will generally fortify them with light vanilla and strong caramel notes too. Already sounding good, yeah?

From here the beer ferments further and it’s as this happens that the biggest flavours and transformations begin. All in all, barrel ageing takes a long time: it’s not uncommon to leave beer in a barrel for at least a year! The results, if you ask me, are usually worth it. Over time you can coax bigger flavours like roasted coffee and burnt toffee out of hiding, along with subtle coconut, roasted almonds and treacle – all depending on the wood and the previous inhabitant, of course.

Can you BA any beer style?

You can; any beer will age, but with wildly differing outcomes. If you try to barrel age, say, an IPA, or something with a similarly subtle flavour, the barrel’s much more grandiose flavours simply stomp all over the encased beer. The big flavours dominate to the point the IPA’s initial flavours are indetecatable. Barrel-ageing IPAs and such, then, is rarely worth the hassle. By contrast, the logical and most commonly BA beers are stouts. Stouts’ big, bold flavours and relative alcohol heft mean they stand up well to the barrels’ attempted bullying. They’re not trampled. They’re turbo-charged.

So just stouts then?

No. Belgian lambics are sour beers that have been brewed and barrel-aged since the 1200s! They lean on the barrel a bit to take the flavour from it but even more so for the brettanomyces. In the case of lambics, the microfauna in the wood start a spontaneous fermentation which creates a skin and spores on the top of the beer… all very geeky, and a bit gross to look at, but the process creates the face-melting goodness and wonderful sour tang that Belgian lambics are famous for.

Why do barrel-aged beers cost so much?

Obviously the barrel-ageing process requires patience and space, hence the hefty price tag of BA beers. Plus, because of the rarity and expense of the barrels in the first place, BA beers tend to be small batch in a world that is already very small batch. These are micro-batch in the scheme of things!

What are the best BA beers I can buy right now?

In terms of dark beers, I’m a huge fan of Nerdbrewing. A small brewery in Sweden, they make a world-famous barrel series and historically they’ve never failed to deliver. The Polish brewery Maltgarden is also a brewery to look out for. In fact, head Maltgarden brewer Łukasz Rokickieven recently dropped into our new venue in Brixton and treated patrons to a BA Maltgarden tasting – the genuine astonishment of those in attendance just proves how otherworldly BA stouts become.

With lambics, 3 Fonteinen are world-renowned. This brewery’s beers marry the classic Belgian sour taste with subtle funky flavours that make things much more approachable than you might otherwise expect. Elsewhere, Cantillon are a little further towards the nerd-end of the lambic scale. You’ll find Cantillon lambics at the top of most aficionados’ must-try lists.

Closer to home, you could do much worse than seek out a BA stout by Emperor’s brewing. Damien, who runs the cuckoo brewery, is heavily, bizarrely and brilliantly inspired by Star Wars, and ages some of the UK’s finest dark beers to perfection time and time again. Emperor’s brews are among the most highly sought-after, limited-release beers you’ll find in the UK. If you’re ever lucky enough to spot one, snap it up!