For more than 100 years, it has kept what it calls an “archive” of whisky that Scottish distilleries have produced.

Gordon & MacPhail was founded in the late 19th century, and was one of the first companies to acquire freshly-created spirit from Scottish distilleries and not blend it with others. 

The company then matured the whisky itself in barrels used to make other spirits.

The so-called single-malt, which at the time made up a vanishingly small proportion of the world’s whisky market, was championed by curators who wanted to develop unique flavours.

The firm now has a huge collection of whiskies from historic and long-closed distilleries that it occasionally bottles and puts on the market. 

Now, after 70 years of maturing a whisky from the Glen Grant distillery, Gordon & MacPhail has uncorked the barrel and is selling bottles to customers for £17,500 each.

For Stephen Rankin, director of prestige, whose great-grandfather John Urquhart selected the whisky for the company collection on June 11, 1948, tasting Glen Grant for the first time is an “emotional experience”.

He tried a dram from the cask with his cousin, who also works for the company. 

“In a nutshell, it’s incredibly smooth, incredibly mellow, but it’s got a huge amount of character and flavour,” he says.

“When you drink something of this sort of age, it takes you back in time to things that were going on back then, in 1948. 

“You’re thinking about the Geneva Convention, which was to come out not long after that. It was years before we started putting men in space, and while various things have happened, this whisky has quietly matured throughout all of that.”

Gordon & MacPhail competed with blended whiskies from labels such as Johnnie Walker and Chivas Regal in an approach that was considered eccentric at the time. The company refers to itself as a “curator and creator”, 
not a distiller.

Mr Rankin describes the Glen Grant as having a dizzying array of flavours, including vanilla fudge, strawberries, raspberries, white stone fruit, orange peel, cinnamon, mahogany, mint and cardamom.

It began life as spirit, produced by the Glen Grant distillery in Rothes, near Elgin. At the time, the distillery would have used traditional whisky-making practices and burned peat as fuel in its distillery.

Gordon & MacPhail, located in Elgin, bought a cask of the spirit and began to mature it in a cask that had transported sherry from Spain. As the spirit matured into whisky, it borrowed the other spirit’s flavours, left over in the wood of the barrel.

For the next 70 years, the cask stayed with the company, being checked regularly by members of the Urquhart family to measure the rate of maturation and the impact of the wood on the spirit.

Last October, the family finally decided the whisky had reached its ideal maturity, and has produced 210 bottles from the 500-litre cask to be sold as part of its Private Collection range.

The Private Collection is a selection of whiskies chosen by members of the Urquhart family from closed or little-known distilleries, which sell for huge amounts of money.

It has a collection of whisky from 100 distilleries in Scotland, of which 26 no longer exist.

Last year, a bottle of the company’s 1943 Glenlivet whisky sold at auction for more than £40,000.

The Glen Grant is bottled at the cask strength of 48.6 per cent in a hand-blown crystal decanter and will be sold on the market for £17,500.

Mr Rankin says there are three types of people who typically pay thousands for a bottle: collectors, investors, and what he calls the “Regular Joes”, for whom the history of a whisky and its rare flavours prove too much to resist. 

“It’s like an antique,” he says. “It cannot be recreated. You cannot go back to the 1940s to remake this, and whisky back then was made differently. People want to try things the way it was. We’ve had regular people who probably live in suburbia, for example, but the story of the whisky will touch them on a level you can’t understand, because it’s personal to them.

“It might be when their mother or father was born, or when their business was started, or when they were born. There’s lots of emotional tie-ins.”

For Mr Rankin, the emotion of drinking the 1948 spirit comes from knowing it is members of his own family that have looked after the cask for decades. 

He said: “My grandfather George would have had a significant role in the selection of whiskies, and he would have done this overseen by his father. He would then have passed on the skills to analyse and check maturing whisky to his children. All that knowledge and history has been passed down to us.”