
Whiskey barrels hold the spirit for a number of years to mature it, with the liquid extracting flavor from the wood.

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.

Although technology has sped up the process of making whiskey barrels, the job of the cooper remains integral to the process.

Flames are fired into whiskey barrels to char them, helping release flavor from the wood.

Hickory wood is often used to make the circular tops and bottoms of whiskey barrels.

"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.

"The tools used to shape the staves and bind them with the hoop (haven't changed much)," says Cox explained.

Whiskey sales have increased globally over the past decade, leading to a flourishing whiskey barrel industry, largely in the US.

The metal hoops that keep the wooden staves together are usually made of iron.

"There is a certain comfort that sometimes doing it the old way, perhaps the slow way, can be the right way," said David Cox.

It usually takes about 32 wooden staves to make a whiskey barrel, which typically has a capacity of 53 gallons.

"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.

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

These barrels are storing whiskey in the Knockando distillery in Scotland.

Barrels at a cooperage in Speyside, Scotland.

Scotch whiskey makers such as Johnnie Walker import used whiskey barrels from the US to repurpose in Scotland.



