Why Does Whiskey Age in Oak Barrels

Bourbon, Scotch Whiskey, Rye Whiskey, Irish Whiskey, and Japanese Whiskey; what do these types of whiskey have in common? If you answered delicious you are absolutely correct, but that is not the right answer. All of these types of whiskey have been aged in wooden oak barrels. For centuries wooden barrels have been used to store and ship many different things becuase it was readily available, easy to make, and had the ability to be reused multiple times.

So whiskey by default has been put into barrels, then when whiskey started becoming popular and demand caused shipping to expand further, the products arriving at their destinations had changed slightly and people started talking. The change was for the greater good and eventually the tipping point for how whiskey would be made for years to come. Next comes the question, which type of wood is used to age and store whiskey? The answer to that is oak. Oak trees are the primary wood source for whiskey barreling. The Whiskey Advocate hits the nail on the head in their article about oak and whiskey, “Without oak, whiskey as we know it wouldn’t exist.”

All whiskey that is distilled comes off the still as a clear liquid with very little flavor and aroma. Based on the type of grain and proof that the master distiller creates, the basic flavors can be more or less noticeable but in no way can flavors of vanilla or honey be created from the distillation process of aging. Oak has the properties concealed within the wood that gives whiskey it’s special flavor characteristics. Although the wood itself may contain the compounds to create these wonderful flavors without the process of charring or toasting these compounds will remain locked within the fibers. The start of charring was either through luck, chance, experimentation or random accident. The act of toasting and charring the wood breaks down the chemicals that release the desirable flavors in the wood.




Different regions have different types of oak trees which produce different flavors. In America the White Oak known as Quercaus Alba imparts flavors of vanilla, caramel, nuts, and toast. In Europe for Irish and Scotch Whiskey they have Quercaus Robur or European Oak which produces more spicy and dried fruit flavors. A side note with Scotch, during the British Empire era wood was scarce because it was prioritized for ship building, so to keep production going distilleries would reuse barrels from wine makers hence the use of sherry port and oloroso casks. For Japanese and other whiskies produced around the world, different species of oak impart unique flavor characteristics that make those types of whiskey so special.

The next big question is, could a distiller use other types of wood to age whiskey or create profiles with different flavors? The answer to this is a definite yes but there are some aspects to consider in that decision. First, if you are trying to produce bourbon the legal requirement is oak so the end product could not be labeled as bourbon. Second, other types of wood such as maple, chestnut and apple can be too brittle and end up cracking or snapping while being made into the barrel. Those types of wood are more porous than oak and would allow for excess leaking and would end up giving the angels a generous portion of your hard work. Lastly, wood such as maple or pine has veins in the wood that contain sap which interferes with the whiskey and adds undesirable flavors to the whiskey.

However, these woods can be used for short periods of time as “finishing” woods to capture some of the unique flavors held within the layers of wood. One such brand that is local to Ohio is the Cleveland Whiskey Distillery Underground Series. These whiskies use oak and other variants of wood to create different palates through the process of aging and finishing. From cherry to maple and hickory to honey locust, these whiskies are intriguing and spark the experimental side of wood flavors and harness the skill to use these woods to create whiskey masterpieces!