KILDARE BEER COLUMN: Over a barrel: how your favourite beer gets its oomph

The perfect beer for cold dark winter nights

Judith and Susan Boyle


Judith and Susan Boyle


KILDARE BEER COLUMN: Over a barrel: how your favourite beer gets its oomph

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Rich, complex beers are perfect for sipping on dark winter nights. Colder nights makes the perfect excuse to enjoy rich, full-bodied beers with added oomph from barrel ageing.

Beers that have been aged in barrels take on the flavours of the wood that the barrel is made from and whatever was previously in the barrel.

Before stainless steel was common place, beers would have traditionally matured in wood.

In traditional breweries across the Czech Republic, lots beer is still brewed in enormous wooden vats. The wood imparts a unique character to the beer, but does not enhance the flavour of the finished beer in the same way a barrel seasoned with whiskey or rum will.

Traditional beers that are barrel aged often have a slightly sour or tangy character due to the influence microbes, living in the wooden barrel staves, have on the flavour of the beer.

We associate these flavour profiles with beers such as barrel-aged Belgian lambics or the slightly tart note often found in traditional porters.

Barrels are an interesting subject. They are highly prized at various points in their lifespan.

Some drinks can only be made from new oak barrels that have not contained any liquids before.

This is the case with bourbon. To be classed as bourbon, the freshly-distilled spirit must be aged in first-fill American oak barrels.

Likewise, some wine makers prize new oak barrels for the flavour the fresh wood will impart to their wines while other wine makers prize barrels that have been filled a number of times before.

And what happens to all the barrels that have been used only once for bourbon?

Well, they go on to have another life, often aging Irish whiskies, other spirits and even beers.

When a beer is place to mature in a bourbon cask, the beer mingles with the bourbon that the wood previously soaked up.

The beer takes on aromas and flavours from the wood and also from the spirit that used to reside there.

Often the percentage alcohol of the beer increases as the high-alcohol bourbon mixes with the relatively low-alcohol beer. This means that you can expect beers that have been aged in barrels that used to contain spirits to be higher in alcohol, usually above 8%.

The beers that are chosen to age in barrels tend to be robust beers that can stand up to and take on the additional flavours from the barrel, so you will often find barrel-aged stouts and porters.

Many different barrels are used for ageing Irish beers.

White Hag and Rascals Brewery have aged beers in wine barrels. On the Irish market we have seen beers from many breweries spend time in Irish whiskey casks or bourbon barrels, and we have tasted beers aged in cognac, rum and tequila barrels.

One of the most well-known example of the symbiotic nature of spirits and beers when it comes to barrel-aging is the Jameson Caskmates series.

Beers were released that had spent time in Jameson barrels and, following that, special edition Jameson whiskey was released that had spent time in the same barrels after the beer.

This series featured Irish beers and breweries and also a number of international beers which were released in different countries.

It is worth seeking out barrel aged beers as they offer a depth of flavour which is very satisfying and delicious.

Many breweries are experimenting with once off barrels so keep an eye out for these delicious beers.

Judith Boyle is a qualified chemist (MSc) and accredited beer sommelier. Susan Boyle is a playwright, artist and drinks consultant. See Both sisters are proud to be fifth-generation publicans. Their family business is Boyle’s bar and off-licence in Kildare town