Beer and barrels have gone together for a very long time, but it’s only in the past couple of decades that brewers have been ageing their beer in barrels previously used to mature bourbon and whisky.

It’s a growing niche, kicked off Stateside but picked up in Scotland with some earth-shattering results. Barrel-aged beers, in most cases, are dark beers, such as a stout or Scotch ale, that have been resting in a whisky or bourbon barrel for at least a couple of months but often up to a year or even longer; the beer literally soaking up the character of the wood – usually oak – as well as the flavours of what went before.

The ABV of these beers pushes the limits, with double figures not unusual. These aren’t session beers then; they’re luxury items to be enjoyed, supped and savoured, after dinner, with a dram and in warm company. They are the perfect Christmas beers and this season you’re in for a treat, with three of the country’s best breweries each bringing out their own barrel-aged beers.

Tempest Brewery in the Borders have at last re-released their Old Parochial Scotch Ale (10%). Aged for six months in barrels from Craigellachie distillery in the heart of Speyside, it has a boozy, ripe and pungent reek – just try not inhaling that thick aroma of red wine, bourbon, Benylin, vanilla, treacle …

A heavy patchwork of flavours wraps around you. Sherry sweet at the offing then glimpses of dried fruits, plum pudding, golden syrup, dark berries, caramel malts, burnt toffee, wood smoke, and a soft, rounded booziness that are all stitched together to present a glorious whole that’s both warm and comforting yet complex and a wee bit dangerous. It finishes gently with a modest whisky-soaked bitterness.

Up in Perth, Inveralmond Brewery have just released their limited edition Ooskabeer, a 7% Scotch ale aged in casks from Glenturret distillery in the Highlands.

The aroma is fresh berries, figs and whisky reminiscences – the smell of Ne’er Days past perhaps. It pours burnt gold, and resting on a backbone of caramel malt is a velvet texture, sweet aromas from the whisky casks. The bitterness here is far more evident; the big sweetness much more reserved; the finishing is surprisingly clean and welcome. It’s an easier beer than the Old Parochial, something of a risk as there’s the temptation for big gulps despite the high ABV.

But it’s Stewart Brewing in Edinburgh who have outgunned all when it comes to barrel-aged beers this Christmas, in terms of appearance, strength, ageing time and cost.

Although, explains Bruce Smith, Stewart’s new head brewer, there’s a bit of mystery to how a barrel-aged beer will turn out, there’s a general rule of good beer in, good beer out. With that in mind he developed an imperial stout with a view to barrel ageing, using a dozen different malts to give it its bold character and body.

Stewart’s three Elysium beers were developed with a view to blending them into one, but after several months it was clear to the Stewarts team that each beer was distinct in its own right. Elysium II came from a Speyside, with the other two (a bourbon and a sherry) coming from a Highland distillery.

Elysium I (bourbon finish) has an earthy reek of red wine, dates and spices, and oozes into the glass, an oily dark, dark brown with a burnt tan head. It’s lightly carbonated and silky smooth, with the coffee and roasted flavours carried along by a wave of booze-soaked fruits and tangy bourbon and vanilla that crashes into a succulent slick of black coffee and dark chocolate bittering at the back.

These beers, great as they are, aren’t the only whisky beers available of course, with more and more breweries knocking on the doors of nearby distilleries. Swannay Brewery offers an Orkney Porter Arran Bere Whisky Cask Edition (10.5%) that is stunningly brilliant; Eden Mill in St Andrews also do a whisky and bourbon barrel beers (7.4%); while Harviestoun in Alva have their Ola Dubh beers (8%) which have been aged in Highland Park casks.