The £36 bottle of whisky you can sell for £2,500

The old bottles of booze at the back of the cupboard that could be worth thousands

Macallan whisky

Do you have a bottle of whisky lurking at the back of the cupboard? Did you put it aside for a special occasion, but never got round to drinking it? Then you could be sitting on a bottle that's worth anything up to £10,000, according to independent antiques valuer and consultant Mark Littler.

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The price of whisky has shot up at a jaw-dropping rate over the past few years. It means that a perfectly affordable bottle of whisky bought twenty years ago could now be worth thousands of pounds. The question is whether the whisky collection gathering dust in the cupboard at home is harbouring a bottle or two that's worth a fortune.

Why is it worth so much?

Littler says: "Scottish whisky only started being marketed beyond Scotland in 1963, and for decades it was only really appreciated by experts and whisky fanatics. Over time, however, the perception has gradually changed, so that an appreciation of whisky became more and more mainstream. In 2007 things really changed, so we were getting the arrival of fashionable whisky bars, offering a huge number of expensive malts. It means that now we have come to appreciate it as something made by craftsmen and in extremely limited supply."

The whisky that you may have bought 20 years ago won't have improved by sitting in a bottle at the back of the cupboard for all this time, however, it is unlikely to have deteriorated, and over that time the perception of the same bottle will have changed dramatically. It means that people will be prepared to pay far more for it - in some cases an astonishing amount more.

What should you look for?

The best value is reserved for the brands that are considered the most desirable. Littler says the most sought after brand at the moment is Macallan, which is one of the oldest and most respected distillers. It also matures its whisky in sherry casks, which makes for a sweeter taste, with a broader appeal, particularly in new markets. Alternatively, for those who prefer a peaty Islay malt, the brand in demand tends to be Bowmore, particularly Black Bowmore.

Mark goes into more detail about the things that can make a bottle particularly valuable on his website, but as a rough rule of thumb the key issues are the age of the whisky when it was bottled (the older the better), the age of the bottle (which tends to get more valuable as they get older), the vintage (not because you get a 'good' and 'bad' vintage, but because the right age of the bottle will attract people buying for birthdays and anniversaries), the level of liquid inside the bottle (too much evaporation can affect the taste), the condition of the label, and whether or not it was a special edition.

Some of the special editions can be worth a small fortune. The most striking example is the Private Eye Macallan. It was launched back in 1996, when it cost £36. Now bottles of it sell for between £2,000 and £2,500.

Similarly, Macallan produced a range of what it called 25 Year Old Anniversary Malts - which aged for 25 years before bottling. The first was released in 1983 and the last was released in 2000. The ones produced in the 1980s and 1990s cost around £80-£100 - and are now worth between £1,500 and £5,000 per bottle.

It also produced a Royal Marriage special edition for the wedding of Charles and Diana. It produced the whisky from two casks, one from 1948 - when Charles was born, and one from 1961 - when Diana was born. Bottles of this whisky are now worth £2,000 or more.

The popularity of the brand means that if you have the right limited edition, even if you've drunk the whisky and just have an old bottle and the box it came in, it could be worth up to £1,000.

Bowmore, meanwhile produced a limited edition Black Bowmore. The first edition was in 1993, and cost £80. The second was released in 1994 and cost £90 and the third was released in1995 and cost £100. Any of these bottles would now fetch between £5,000 and £10,000.

The fourth edition was released in 2007, and while it cost a more eye-watering £2,400, it is now worth between £20,000 and £30,000. The final edition in 2014 cost £16,000. As Littler says: "You can see how the perception of the distiller changed over 20 years."

Other distillers won't have seen such astounding growth in value, but may well have increased substantially. Littler says names to look out for include Ardbeg, Brora, Glenlivet, Glenfarclas, Glenmorangie, Highland Park, Lagavulin, Springbank, Laphroaig, Mortlach, Macallan, Port Ellen. If you have an old bottle of any of these, it could be worth more than you think.

Can you cash in?

If you have an old bottle from a prestigious distiller, it's worth having it valued. One of the frustrations of selling them is that you cannot do it yourself through eBay without a licence, so you need to go through a broker or an auction house. However, as Littler points out, the advantage of this system is that you don't have lots of online sellers trying to undercut one another, which is helping to keep prices buoyant.

The question of whether you should hold on or sell now is never easy to answer. Littler highlights that typically as bottles get older, more of them are drunk, and so they get rarer - pushing the price up. However, given that Macallan prices have shot up - and in the case of the Private Eye edition are up more than 6000% since 1996, it's hard to imagine how that growth will be sustainable, so it may be that now is a great time to sell.

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