Speyside Cooperage in Craigellachie, Moray, employs 14 coopers who each repair up to 15 to 30 casks a day for the Scotch whisky industry.
It’s a craft that was first recorded 5,000 years ago with the hammer and driver remaining the main tools at work, but machines now help to remove rivets and metal bands to help quicken the process and take away some of the heavy grind.
At Craigellachie, one cooper started his apprenticeship aged 15 and is still working at the cooperage, aged 63. Today, 23 apprenticeships are learning their craft with the company, split between their sites in Moray and Alloa.
On the last day of an apprenticeship – which takes four years – the cooper is stripped to their underwear, put in a large cask, pelted with sawdust and paint, and rolled around the cooperage floor in the traditional ritual of the ‘blackening’.
The casks that come in for repair broadly come from the bourbon bonds of Kentucky, where the law dictates they are made from American Oak and used only once.
Around two million casks of bourbon are produced every year, with the casks then sold onto distillers around the world.
Andrew Russell, general manager of Speyside Cooperage, said: "Because Kentucky bourbon law dictates that you can use a cask only once, there are an awful lot of casks out there, which is very good for Scotch whisky."
Once the casks are used by the whisky industry three or four times, they will arrive at Craigellachie for repair.
The casks may also need to go through the “dechar – rechar” process where the old carbon layer from the original charring is shaved off.
“Then we rechar, which is basically setting the inside of the cask on fire,” Mr Russell said.
Whether the distillery wants fresh char depends on the style of the whisky to mature in the cask, with the cooperage serving various brands across the country.
At Craigellachie, the cooperage is the only one in the UK where a visitor centre shines a light on the craft and the traditions that help to form that perfect drop.