Behind the Forecast: Can Weather Change Bourbon’s Flavor?

LOUISVILLE, Ky. (WAVE) - Bourbon is a Kentucky staple. As wild as Kentucky’s weather is, it plays a vital role in your favorite bourbon’s flavor.

The batch of bourbon that goes into a barrel is called “white dog.” There’s not much flavor in this part of the process; there’s only a hint of grain. In warm weather, the bourbon barrel’s wood expands, allowing the bourbon to seep into the barrel’s pores, collecting wood particulates. When temperatures drop, the alcohol is pulled back out of the wood, taking particulates with it - giving it that bourbon flavor.

Extreme cold temperatures prevent the bourbon from seeping into the barrel’s pores, while heat evaporates too much spirit (also called angel’s share).

Many rickhouses are not temperature controlled, allowing for temperature variation in these buildings. Barrels closest to the walls and in higher racks have the most significant temperature variation. With that variation, these barrels will absorb more flavor than barrels in the rickhouse’s interior.

Many distilleries are switching their focus to local grain sources as the climate changes. Updated precipitation normals in Kentucky and Indiana point to increasing regional precipitation due to climate change.

Rising temperatures, with the rise in precipitation, can impact crop yields across the state. Corn (which makes up 51% to 81% of bourbon’s mashbill) is Kentucky’s top crop. Higher precipitation and temperatures can negatively affect corn yields. There is a push to increase rye production in the state as well. However, rye (the second grain used in many bourbons) is difficult to grow in Kentucky because of the humid, warm climate. An increase in humidity due to higher temperatures would make that even harder.

Most bourbon barrels are made of American white oak, which grows throughout the eastern United States and southern Canada. As the bourbon industry booms, many wonder if there’s enough white oak to support production. Sustainable forestry practices will ensure that tree growth consistently exceeds the harvest.

As we enjoy our favorite Kentucky bourbon, raise a glass to how the weather can help and hurt the state’s signature beverage.