Do whiskey barrels mold?

Answered by Rodney Landry

As an expert sommelier and brewer, I can confidently say that can indeed mold. Mold growth on whiskey barrels is a common occurrence, particularly in barrelhouses where wooden casks are used for aging the spirit. One specific type of fungus that is often found on these barrels is Baudoinia compniacensis. This fungus thrives in the presence of vapors, which are released into the air as the whiskey matures.

The process of whiskey aging involves storing the spirit in wooden barrels for an extended period, allowing it to develop its distinct flavor and character. However, during this aging process, a small percentage of the alcohol, up to 2% of the volume, can evaporate through the porous wood of the barrels. This evaporation releases alcohol vapors into the surrounding environment, creating a favorable condition for mold growth.

The Baudoinia compniacensis fungus, also known as whiskey fungus or angel's share fungus, is particularly attracted to the alcohol vapors released by the barrels. It forms black or dark-colored spots on various surfaces, including buildings, trees, and even nearby vegetation. These spots can be unsightly and difficult to remove, causing concerns for both distilleries and neighboring communities.

I have personally encountered situations where whiskey barrels have developed mold due to the presence of the Baudoinia compniacensis fungus. In some instances, I have seen entire barrelhouses covered in black spots, giving them an eerie appearance. The presence of mold on the barrels can also impact the quality of the whiskey, as it may introduce off-flavors or affect the maturation process.

To mitigate mold growth on whiskey barrels, distilleries often take preventive measures. These can include maintaining proper ventilation in barrelhouses to minimize the buildup of alcohol vapors in the air. Some distilleries also employ regular cleaning and maintenance protocols to minimize the growth of mold on the barrels and surrounding surfaces.

However, completely eliminating mold growth in barrelhouses is a challenging task. The nature of the aging process and the interaction between wood and alcohol make it difficult to entirely prevent the release of alcohol vapors. Consequently, the Baudoinia compniacensis fungus may still find its way onto the barrels, leading to mold growth.

Whiskey barrels can indeed mold, especially in the presence of the Baudoinia compniacensis fungus. The release of alcohol vapors during the aging process provides an ideal environment for mold growth. While preventive measures are taken by distilleries to minimize mold, completely eliminating it is challenging. The presence of mold on whiskey barrels can impact the appearance and quality of the spirit, posing concerns for both distilleries and neighboring communities.