Whiskey barrels hold the spirit for a number of years to mature it, with the liquid extracting flavor from the wood.
Whiskey barrels hold the spirit for a number of years to mature it, with the liquid extracting flavor from the wood.
Jamie Fullerton
American white oak is the most commonly-used wood to make stave -- the long sections of wood which make up the main part of the barrel.
American white oak is the most commonly-used wood to make stave -- the long sections of wood which make up the main part of the barrel.
Brown-Forman
Although technology has sped up the process of making whiskey barrels, the job of the cooper remains integral to the process.
Although technology has sped up the process of making whiskey barrels, the job of the cooper remains integral to the process.
Brown-Forman
Flames are fired into whiskey barrels to char them, helping release flavor from the wood.<br />
Flames are fired into whiskey barrels to char them, helping release flavor from the wood.
Jeff J Mitchell/Getty Images Europe/Getty Images
Hickory wood is often used to make the circular tops and bottoms of whiskey barrels.<br />
Hickory wood is often used to make the circular tops and bottoms of whiskey barrels.
Jeff J Mitchell/Getty Images Europe/Getty Images
"There's something elemental about making casks -- there's a romance to it," said David Cox, former director of fine and rare whiskeys for The Macallan, a single malt distillery that has produced rare whiskeys since 1824.
"There's something elemental about making casks -- there's a romance to it," said David Cox, former director of fine and rare whiskeys for The Macallan, a single malt distillery that has produced rare whiskeys since 1824.
image via Jack Daniels
"The tools used to shape the staves and bind them with the hoop (haven't changed much)," says Cox explained.<br />
"The tools used to shape the staves and bind them with the hoop (haven't changed much)," says Cox explained.
Jeff J Mitchell/Getty Images Europe/Getty Images
Whiskey sales have increased globally over the past decade, leading to a flourishing whiskey barrel industry, largely in the US.<br />
Whiskey sales have increased globally over the past decade, leading to a flourishing whiskey barrel industry, largely in the US.
Jeff J Mitchell/Getty Images Europe/Getty Images
The metal hoops that keep the wooden staves together are usually made of iron.<br />
The metal hoops that keep the wooden staves together are usually made of iron.
Jeff J Mitchell/Getty Images Europe/Getty Images
"There is a certain comfort that sometimes doing it the old way, perhaps the slow way, can be the right way," said David Cox.<br />
"There is a certain comfort that sometimes doing it the old way, perhaps the slow way, can be the right way," said David Cox.
Jeff J Mitchell/Getty Images Europe/Getty Images
It usually takes about 32 wooden staves to make a whiskey barrel, which typically has a capacity of 53 gallons.<br />
It usually takes about 32 wooden staves to make a whiskey barrel, which typically has a capacity of 53 gallons.
Jeff J Mitchell/Getty Images Europe/Getty Images
"It's made in the shape it is so you can steer it when you're rolling it like a wheel," says Jeff Arnett, master distiller of Jack Daniel's.<br />
"It's made in the shape it is so you can steer it when you're rolling it like a wheel," says Jeff Arnett, master distiller of Jack Daniel's.
Gonzalo Jaen
Whiskey barrels house the spirit for a number of years to allow the drink to mature before it is bottled.<br />
Whiskey barrels house the spirit for a number of years to allow the drink to mature before it is bottled.
Gonzalo Jaen
These barrels are storing whiskey in the Knockando distillery in Scotland.<br />
These barrels are storing whiskey in the Knockando distillery in Scotland.
Gonzalo Jaen
Barrels at a cooperage in Speyside, Scotland.<br />
Barrels at a cooperage in Speyside, Scotland.
Gonzalo Jaen
Scotch whiskey makers such as Johnnie Walker import used whiskey barrels from the US to repurpose in Scotland.<br />
Scotch whiskey makers such as Johnnie Walker import used whiskey barrels from the US to repurpose in Scotland.
Jamie Fullerton
The art of crafting whiskey barrels

Story highlights

The art of making a barrel is one of the most overlooked aspects of creating a fine whiskey

The type of barrel the spirit is stored in has an enormous influence on its taste

CNN  — 

“The story of the barrel is one of the overlooked crafts of whiskey-making,” says Jeff Arnett, master distiller of American whiskey brand Jack Daniel’s.

Indeed, the type of barrel the spirit is stored in has an enormous influence on its taste, making the art of cooperage – the crafting of the barrels – an essential part of the whiskey-making process.

American white oak is the most commonly used wood to make staves: long sections of wood that make up the main part of the barrel
American white oak is the most commonly used wood to make staves: long sections of wood that make up the main part of the barrel
image via Jack Daniels

It’s a process that still relies on a huge amount of human skill despite advances in technology streamlining production.

“The tools used to shape the staves and bind them with the hoop (haven’t changed much) … It’s still a hand-crafted business,” says David Cox, the former director of fine and rare whiskeys for The Macallan, a single malt distillery that has produced rare whiskeys since 1824.

He adds: “There’s something elemental about making casks. There’s a romance to it.”

‘An amazing sight’

The process of making a whiskey barrel usually begins with a stock of American white oak. This is the most commonly used wood for whiskey barrels, largely due to how leak-resistant it is and the flavors it imparts into spirits. Most whiskey barrels are made in the US, where white oak grows.

Hickory wood is often used to make the circular tops and bottoms of whiskey barrels
Hickory wood is often used to make the circular tops and bottoms of whiskey barrels
Jeff J Mitchell/Getty Images Europe/Getty Images

“American white oak gives a vanilla, coconut, creamy kind of flavor,” says Matthew Crow, wood and cask science manager for Diageo, the drinks company that owns Johnny Walker, “compared to European white oak, which gives a dried fruit flavor with more spice.

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Coopers divide the wood into the long body sections, called staves, ensuring its rings are at right angles to the wood’s wide face. This minimizes the chance of the wood warping and makes it more water-resistant.

After the circular wooden tops and bottoms are attached, the staves are placed in a belt-like iron hoop before being bent – usually by softening the wood with steaming – into the signature curvy shape of a whiskey barrel.

(“It’s made in the shape it is so you can steer it when you’re rolling it like a wheel,” says Arnett.)

Charring the barrel -- flames are fired into whiskey barrels to char them, helping release flavor from the wood
Charring the barrel -- flames are fired into whiskey barrels to char them, helping release flavor from the wood
Jeff J Mitchell/Getty Images Europe/Getty Images

The next stage is to char the barrel by firing flames inside it. Barrels usually pass through gas-powered flaming systems on conveyor belts. This extracts flavor from the wood, which seeps into the spirit during the whiskey’s maturation process, which lasts for a number of years depending on the brand and style.

The charring process is, “an amazing sight to watch,” Cox says.

An enduring image

With global demand for whiskey increasing, demand for barrels could get even bigger.

In the US, whiskey sales have been growing for a decade, rising 6.8% from the previous year in 2016, with $3.1 billion of sales to wholesalers. Recently the?price of scotch, perhaps Scotland’s most famous export, has risen due to a similar spike in popularity. Japanese whiskey has also?boomed both domestically and abroad.

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Crow says that the cooper will remain intrinsic to the whiskey-making process. Speaking about Diagio’s cooperages in Scotland, which repurpose barrels bought from the US for Scotch whisky, he says: “We have robotics to place the casks … but there’s still a traditional, manual skill at work.”

Whiskey barrels house the spirit for a number of years to allow the drink to mature before it is bottled
Whiskey barrels house the spirit for a number of years to allow the drink to mature before it is bottled
Gonzalo Jaen

“We treat used barrels by scraping their inner surface to remove old char, then re-char and re-burn them. There’s a real focus on the manhandling aspect.”

Cox is also happy robots aren’t taking over the main crux of production.

“In a time of great technological change, there is a certain comfort that sometimes doing it the old way. Perhaps the slow way can be the right way,” he says.