A Jameson Black Barrel masterclass in coopering with Ger Buckley

Irish Distillers' master cooper talks wood, cask charring, and Jameson Black Barrel. Words: Laura Carl. 

Who doesn’t love delicious Irish whiskey? We certainly do here at Milroy’s. Neat, on the rocks, mixed with ginger ale or used as an ingredient in a cocktail, Irish whiskey always manages to leave its distinctive mark. The liquid’s unique history is entwined with cask creation and wood selection. We took a deep dive into this rich heritage with Jameson master cooper, Ger Buckley, to find out more about how the cooperage helped shape the world of Irish whiskey.  

Buckley has been creating, repairing and charring barrels since 1976, with his skills passed down from his father. Coopering runs in his blood. His family has been working in the craft for over 200 years, Buckley being a fifth-generation master cooper. 

Buckley explained that barrels have been around for over 4,500 years. While they date back to Ancient Egypt, the way we make barrels has not changed in over 200 years ago. The only difference in the barrels we see today is the use of metal hoops instead of wooden ones. Previously, metal was allocated towards making weapons and tools. This is a good bit of trivia for historical inconsistencies in movies and tv shows! 

Irish coopering: the importance of oak

Even more so than Scotch or Bourbon, wood is at the heart of Irish whiskey’s heritage. It has allowed the category to develop a unique set of characteristics that sets it apart from others. This all comes down to the law. In Scotland, whisky must be matured in specifically oak barrels, but Irish whiskey regulation states only wood. This allows distillers to select from a variety of materials to impart different flavour compounds into their maturing spirit. The majority of distilleries use American or European white oak, but this creative freedom has allowed distilleries such as Method and Madness to play with chestnut, maple, cedarwood and mulberry.  

Though The Emerald Isle is famously covered in dense woodland, the whiskey industry hasn’t used Irish oak to mature spirit in about 150 years. American or European oak is preferred. A lot of Irish wood went into smelting, burned to create charcoal for the high temperatures required to melt metal before the use of coal. 

Why is this important? Casks are an essential component in the creation of whiskey. They impart flavour, colour and depth. Wood selection is as important as the distillation process itself – neither can create a well-balanced liquid without the other.  

And the specific type of wood is important, too. For example, white oak produces sweet caramel and vanilla notes due to its particularly prominent vanillin compounds. European white oak produces a different array of flavours such as dark fruit, nectarines and plums. Imagine how using different wood types can influence flavour. 

Wood variety can affect the level of angels’ share lost to evaporation. Depending on the porous nature of the wood, and assuming constant temperature and humidity, this can be 2% for oak, compared to 7-8% for other wood types. Red oak can’t be used at all.  Its large veins make it too porous, resulting in leaks. And no-one wants that. 

The role of the cooper

Now an expert in his field, Buckley had to learn the precision needed to create a barrel over time. His only tools? A Compass to measure, an Axe to cleave and a Cooper’s Croze to shape. The rest is done by eye and scale. No two barrel staves are the same. Each one is selected to fit next to the other by the eye of the cooper. Any mistake made, at any point in the process, will lead to a leak. The tools alone show how little the art of coopering has changed over the centuries. Buckley’s broad axe, which belonged to his father, dates back over 100 years – it’s exactly the same tool as those used in Roman times.  


Why toasting and charring matters


It was time to learn about how to ‘raise’ a cask. After expertly deconstructing a barrel to a pile of 32 staves in a matter of seconds, Buckley’s discussed the importance of toasting and charring. Charring is the process of heating the inside of the barrel prior to filling it. There are no reliable records to show where and how it began. Many believe the process was carried out to reduce moisture levels and risk of wood rot. Others think it was a way of cleaning the barrel after storage to rid it of lingering aromas or flavours. Whatever the reason, whiskey producers found whiskey stored in charred barrels matured faster and tasted sweeter than those stored in un-charred casks.  

The reason this happens is all down to chemistry. When heated, the wood is altered on a molecular level. Large components such as cellulose and lignin are broken down into smaller, highly dissolvable molecules which impart flavour into the liquid. The charcoal also acts as a form of filtration to remove harsher sulphates from the liquid. The latter is known as subtractive maturation. 

Charring can range from light to heavy, with each barrel being given a rating of 1 to 5. Each barrel is heated from 20-45 seconds to achieve the desired level of burn – this will impact flavour. In the case of Jameson Black Barrel, the process is doubled in order to achieve heaviest effect possible – the alligator char. So called because of its resemblance to alligator skin, it imparts rich caramel flavours into the triple-distilled Irish whiskey. For this expression, it’s then matured for up to 16 years. 

Toasting is a slower process, lasting up to 10 minutes. The wood is heated but never exposed to a naked flame. This technique is used in wine barrels, so whiskies aged in ex-sherry casks will be interacting with toasted oak.  

If you drink wine or whiskey, you’re probably familiar with the term ‘tannins’. Buckley explained that charring helps to break down the tannins in wood which can give the whiskey a bitter taste. Fascinatingly, he went on to explain how a tree will use tannins to repel attacks from animals and insects. It will release tannins into their leaves as they are eaten to make them taste bitter – the theory is it’ll discourage the creatures from coming back. Remarkably, these tannins also act as a signal carried through fungal networks in the ground to warn other trees of an incoming threat. 

Finally, Buckley regaled us with stories of his youth. He recalled seeing his father wearing a full suit to work in the cooperage – it was a prestigious craft and he held it in high regard. He covered his suit with an apron to ensure that the only part blackened by soot was his hands.  

It’s a craft that’s remained unchanged for generations. The cooper’s traditions will be carried on by Ger and those who follow in his footsteps.  

You can buy Jameson Black Barrel Irish Whiskey here for £39.95. 

Try Jameson Black Barrel in an Irish Wolfhound


Build all ingredients over ice in a highball glass filed with ice. Garnish with a grapefruit slice and enjoy!