How the volatile weather of Tennessee serves as a key ingredient to Jack Daniel’s whiskey

LYNCHBURG, Tenn. (WTVF) — In 1866, the first registered distillery in the United States began in the quaint town of Lynchburg, Tennessee! Today, Jack Daniel’s is the top selling whiskey in the world. Known for its consistency, every drop made is made in Lynchburg.

So how is it that even though the whiskey is made in a volatile climate, the product isn't impacted by the weather?

It all starts with the water.

To make whiskey, it must be free of iron. Otherwise it would turn black and bitter. One point that led Jack Daniels himself to choose the location of Lynchburg was the natural spring water — and more importantly — the presence of limestone in the area. Limestone acts as a filter, removing iron from the water. When it rains, water is absorbed into the ground through the limestone, eventually making its way down to a spring.

Someone who knows a thing or two about the cave spring is Jack Daniel’s Master Distiller, Chris Fletcher. Chris’s roots with Jack Daniel’s are deep as his grandfather, Frank Bobo, who served as master distiller from 1966-1988.

“That cave system goes two miles deep into the ground,” Fletcher said.

Inside that cave spring, the temperature remains steady.

“56 degrees, as far as I know, that’s about the ground temperature here as you get so far down," Fletcher said.

Regardless of the temperature outside, whether it’s zero degrees or 100 degrees, this natural spring remains a constant 56 degrees! How is this possible?

The answer lies in the shape of the cave — it doesn't allow cold air to be pushed out and replaced with warm air.

A routine check ensures the water remains healthy.

“We’ve had it mapped and studied, and about every few years we’ll have people go back in and consider the health of it and make sure it’s all structurally sound,” Fletcher said.

After water, the quality of the grain is a major component of what sets this whiskey apart — an ingredient we see directly impacted by the weather. If a region is drought-stricken, limiting or damaging a crop, Jack Daniel’s will look as far as Canada and Northern Europe to find its grain.

“We have pretty tight specifications, even with our corn. It’s number one grade corn, it’s cleaned. We don’t want to bring in number two here and worry about fishing out sticks and stones, or husk, or whatever might be in there. We have very tight moisture specs. We want a certain amount of starch in there which is what will be turned into the whiskey,” Fletcher said.

To make this spirit a true Tennessee whiskey, the special step of charcoal mellowing must happen next. But it cannot be just any charcoal. It’s a charcoal created on-site at Jack Daniel’s using Hard Sugar Maple Wood.

“To be a Tennessee Whiskey it has to touch that Hard Sugar Maple Charcoal,” Byron Copeland, Manager or Maturation and Innovation at Jack Daniel’s, said.

Also known as the “Lincoln County Process,” the distilled whiskey is sent through ten-foot-tall tanks of self-made charcoal, filtering out impurities and giving the whiskey a smoother taste.

Now it’s time to age the whiskey by storing it in a barrel. But the whiskey cannot be put in just any barrel.

“They are made of oak. In order to be a bourbon, or Tennessee whiskey they have to be made of new, charred oak. But what we use is white oak,” Copeland said.

Copeland says the white oak used comes from Appalachia. States such as Alabama, Tennessee, Virginia, West Virginia, and Kentucky are where they mainly turn to for the white oak used for their barrels. They also will look to Missouri where there is white oak that meets their specifications.

With such a large region that grows white oak needed for this whiskey, there's somewhat of a safety net should one area be experiencing some sort of extreme weather.

Once that wood is cut, Jack must take care to ensure it doesn't dry out and splinter as it makes its way to the distillery.

“The way you make sure they don’t fall apart; you want to make sure to keep some water in there so that wood stays moist," Copeland said.

Now the long aging process begins, and temperature changes come into play — from sweltering Tennessee summers to bitter cold winter months.

Copeland points out that in the wintertime, the whiskey contracts inside the barrels coming out of the wood into the barrel. In the summertime, the whiskey expands absorbing into the barrel stave. Over time, this is the process that gives the whiskey 100% of its color and between 60% to 70% of its flavor.

From the water, to the grain, to the oak used to make whiskey barrels — they all serve a special purpose to make Tennessee’s second largest export.

And despite extreme cold in the winter — or extreme heat in the summer — remember that a small town in Middle Tennessee harnessed both for decades to make the most recognized whiskey brands in the world!