Jack Daniel’s is the only distillery in the world that still makes their own wooden barrels. It is an intriguing process requiring a lot of workers, machines and a very precise amount of fire. You can watch a very cool video of the process here (along with some great music).

To go along with the video, here’s an explanation of what it takes:

Firstly, wood oak is sourced from the United States by the Brown-Forman, the company that owns Jack Daniel’s and transported to their cooperage site. As this new wood is full of water, it first needs to dry out. This takes a year before the wood is sufficiently ready for the next step.

To enhance the flavour of the wood, it is actually aged and dried in the outdoor elements for six to nine months. This aging process helps to stabilize the bitter tannic acid in the wood and smooths out the final taste of the product by adding colour as well as notes of spice and fruit.

After aging outdoors, the drying out process is completed by exposing the oak to hot heat in a warehouse-sized kiln. At this point, the wood planks are shaped into staves that make up the body of the barrel, while the lids are made by pinning planks together and cutting them into a sphere. Each stave is fitted by hand. This is essential to the outcome as the workers ensure that the resulting barrels are watertight and secure.

The barrels are next subjected to 450 degree Fahrenheit temperatures to break down the vanillins in the wood. These elements are released into the whiskey to help give it flavour. The charring process follows as the open barrels are put on a gas burned and lit on fire. Temperatures reach as high as 1500 degrees Fahrenheit, carmelising the sugar in the wood and adding yet another note of flavour to the whiskey. The charring process takes approximately 30 seconds.The lids of the barrel,s which are charred separately, are then fixed to the ends of the barrel.

A little hole is then made in the barrel to ensure no whiskey leaks. The barrels are filled with water first to test their quality before the actual whiskey goes in.

Finally the barrels are sent to the Jack Daniel’s Distillery in Lynchburg, Tennessee to begin the aging process. As the spirit ages, the barrels are kept in wooden barns that have no heating or cooling systems in place, relying instead on Tennessee’s natural weather to provide the necessary expansion and contraction as time passes and seasons change. As this happens, the whiskey soaks into the wood, dissolving the tannings and carmelized sugars.