Whisky itself, when first distilled, is a clear, colorless liquid. The rich, golden hues and darker tones that whisky is famous for are imparted entirely by the barrels in which it is aged. When barrels are filled and sealed with a bung, a piece of burlap or hessian cloth is placed under the bung. This serves several important purposes beyond the obvious practicalities.

One lesser-known aspect is the role this cloth plays in the maturation process. As the whisky ages in the warehouse, the burlap acts as a buffer, absorbing and releasing moisture in response to changes in humidity and temperature. This subtle interaction can influence how the whisky interacts with the wood, potentially affecting the flavor profile over time.

There’s also an old tradition among coopers, who believed that the cloth under the bung allowed them to “listen” to the cask. By adjusting the bung’s tightness with the cloth beneath it, they claimed they could gauge the maturation process by the sounds or slight air releases from the cask. While this practice is more of a craft tradition than a scientific method, it reflects the deep intuition and experience involved in traditional whisky-making.

Historically, the burlap also served to protect the cask from pests and prevent mold around the bung, particularly in less controlled, damper environments. This small detail provided an additional safeguard for the aging whisky.

Here, you can also observe the different characteristics imparted by various barrels. For example, a deep, rich color suggests the cask previously held Spanish sherry, Madeira, or port wine, while a lighter hue indicates American bourbon barrels. Notably, there’s a special cask dedicated to King Charles, placed here in 2021, symbolizing the ongoing tradition and royal connection to this distillery.