Why Oak?

By Chris Morris • Photo of Chris Morris by Matt Johnson | Photos of Barrels Provided by Woodford Reserve

In previous issues of the Voice, we have examined the global standard of identity for Whiskey, in other words we discussed what makes a Whiskey a Whiskey. We followed that with a deep dive into the standards that govern the production of Bourbon Whiskey. And most recently, we have looked at the historical reasons for the use of corn as the predominant ingredient in the production of Bourbon Whiskey. Corn certainly is one of the factors that separates Bourbon Whiskey from the other great Whiskeys of the world like Single Malt Scotch. But the use of corn is not the only outstanding difference.

The bourbon standards also require that the corn rich distillate be matured in oak containers, like the global standard for Whiskey requires, but that the oak containers be both new and charred on the inside. Scotch, Irish, and the other international Whiskey types do not require the use of either new or charred barrels for their maturation vessels. The global standard for Whiskey simply requires the use of oak containers in the maturation process. So, the use of a new charred oak container and let’s call it a “barrel” is one of the definitive requirements/ingredients that separates Bourbon Whiskey from all other international whiskey types. 

This leads to the question - why are oak barrels required in the crafting of Whiskey? Why not use some other type of wood? Why even use wood? Again, history and environmental conditions supply us with the answer. First, let’s go back in time to the types of storage vessels that the ancient world used to hold liquids. The archaeological record is quite clear – liquids were stored in fired clay vessels, in other words, “ceramics.” As far back as 9,000–10,000 BCE pottery vessels were used for storing food and water. Storing a liquid in a ceramic vessel will not change the liquid. It simply contains and protects it.

Early civilizations like the Egyptians had made crude types of wooden barrels that would not hold liquid. These were used along with baskets and boxes to store dry goods. Why didn’t these early barrels hold liquid? The wood that was used was the wrong kind! At Brown-Formanwe have experimented with making barrels from other types of wood. These included maple, hickory, ash, beech, birch, cherry, and pecan. None of them held liquid like an oak barrel does. Plus, some gave undesirable flavors to the liquid (Whiskey) we stored in them. Other types of wood, like pine, can’t be easily bent into the shape of a barrel and it is the shape that gives it its strength and versatility.

The modern style of wooden barrels has been used for the transportation and storage of goods for around 2000 years. The timing could not have been better for the introduction of barrels made from oak. This was a time of rapidly evolving trade, and the ceramic vessels of the time were fragile. Moving valuable goods like olive oil and wine in them long distances over rough roads or by ship was a risky business. If the container was dropped or jolted during transit it could break, and its contents lost. On the other hand, wooden barrels were both durable and easy to handle. Their shape with the bulge in the middle made barrels easy to roll and turn. The widespread use of barrels developed along with the growth and evolution of trade.

Early civilizations like the Egyptians had made crude types of wooden barrels that would not hold liquid. These were used along with baskets to store dry goods. Why didn’t these early barrels hold liquid? The wood that was used was the wrong kind! I have experimented with making barrels from other types of wood. These included maple, hickory, ash, beech, birch, cherry, and pecan. None of them held liquid like an oak barrel does. Plus, some gave undesirable flavors to the liquid (Whiskey) we stored in them. Other types of wood, like pine, can’t be easily bent into the shape of a barrel and it is the shape that gives it its strength and versatility.

It was the Roman empire that introduced the world to oak barrels. As the Romans expanded their Empire into what is now Central Europe they encountered the Celts. The Celts are credited with the development of the modern barrel around the beginning of the first millennium. They inhabited a temperate zone that oak thrives in – so when they made barrels from the prominent local wood it was discovered that it was the wood of choice. It was tough but pliable and most importantly it held liquid. As in the case of most discoveries, probably an accident or an oversight occurred when a barrel made from oak, intended to be filled with dry goods, was filled with a liquid and it was discovered that the barrel held that liquid. It could’ve been water, wine, beer or something else but it doesn’t matter, an important lesson was learned. 

The Romans capitalized on this discovery and began to use oak barrels throughout their Empire’s vast trade routes. As certain liquids spent time in these oak barrels during their journey to market it was discovered that they had changed. Unlike a ceramic vessel, an oak barrel imparted flavor to the liquid stored in it. In some cases, for the better! So naturally once Whiskey was created it too would eventually be stored and transported in oak barrels like other liquids. And it would improve as well.

So today Whiskey is required to be stored in oak barrels due to the history of how our ancestors stored and moved liquids. This resulted in the eventual realization that the oak barrel had become a part of the Whiskey flavor profile. So why oak? Why change a good thing!