The next stage of the story in making Irish whiskey is maturation, or in other words, ageing. This part of the journey from grain to the bottle starts with the spirit that has been produced from distillation being filled into wooden barrels, also known as casks. The Irish Whiskey Act on the Irish Statute Book states that Irish whiskey must be matured on the island of Ireland for not less than three years.
The wooden barrels used for Irish whiskey maturation are usually American White Oak or European White Oak. Irish whiskey can be matured using various kinds of wood other than oak. Experimentation with different types of wood in the maturation process of Irish whiskey is cause for much excitement in the industry, as distilleries and bonders seek to create excellent new and creative Irish whiskeys. The Irish Whiskey Act accommodates innovation by specifying that Irish whiskey needs to age “for at least three years in wooden casks, such as oak, with a maximum capacity of 700 litres.” In contrast, Scottish law, per the Scotch Whisky Regulations, mandates that whisky must be “aged solely in oak casks not exceeding 700 litres.” Limiting the cask size to 700 litres is based on the maturation quality; larger vats exceeding 1000 litres would not sufficiently enhance the whiskey’s flavour and character during the ageing process.
The Barrels, also called casks, are commonly charred on the inside before use. The charring process allows sugar from the oak to transfer to the whiskey more easily by adding the congeners we want, like vanillins and lactones – contributing to the whiskey’s beautiful aroma and flavour. Conversely, as it ages, a charred barrel removes undesirable compounds like ethanol, tannins, and sulfur from the whiskey. Charring also creates a larger internal cask surface area and, thus, an opportunity for greater contact between the spirit and the wood, allowing for more chemical interaction inside the barrel.
These interactions are the most natural part of the whiskey production process, where the two most essential characteristics of the master distiller are patience and trust in the process. In other words, it is time for the wood and spirit within to work their magic. McCarthy’s Irish Whiskey Premium Blend is patiently aged in imported American White Oak barrels, previously used to mature American Bourbon Whiskey. It is from these ex-fill bourbon barrels that McCarthy extracts its sweet butterscotch and vanilla notes into the whiskey. As McCarthy’s is distilled three times, like most Irish whiskey, you have a more delicate and smooth spirit than Scotch. This allows the wood to influence the whiskey even more.
Irish Whiskey Finishing
In addition to Irish whiskey’s openness to the type of wood barrels that can be used, this also extends to the finishing options. Finishing uses a second barrel of a different type than the first American Oak. Irish whiskey can be finished in any previously seasoned barrels containing wine, beer or other spirits. This has led to outstanding creativity in the landscape of Irish whiskey.
McCarthy’s 5-Year-Old Single Malt Cask Strength is bottled directly from its American Oak Barrel.
The flavours from a finishing barrel are often a bit more subtle. The whiskey’s time in the second barrel varies depending on the desired flavour profile. Some typical finishing options for Irish whiskey are sherry, port or marsala casks. These impart flavours that are unique to the liquid yet will ultimately be complementary when the whiskey is bottled. McCarthy’s Premium Blend is finished in ex-fill sherry, European Oak Barrels. The sherry barrel bestows notes of floral and orange peel on the whiskey. At McCarthy’s, we source our spirit at the Great Northern Distillery in Co. Louth. As independent bonders, we mature the new make spirit, blend it and bottle it in a way that expresses the kind of Irish whiskey we want our customers to enjoy. Our Premium Blend has already picked up three awards in the USA and is the core expression. In future releases and special editions of McCarthy’s Irish Whiskey, we will experiment with and mature our spirit in different types of wooden casks we have sourced around Europe.
For 2024 we are working on several magnificent unique additions to the McCarthy’s range heretofore not seen or tasted in the Irish whiskey.
