Sunlight and Whisky

[Lord Neville Crispin]

Greetings.

I recently moved my small collection out of the cupboard and onto a shelf in my living room. However, I noticed that, at various points during the day, the sun directly hits the bottles. Now some of them are still in their cylinders, but a few aren't. I was wondering if direct sunlight could hurt the whisky in any way and if I should move them to a less well-lit and warm area.

[Count Silvio]

A distiller once said to me that sunlight can cause color changes in a spirit and affecting the taste through that. I think it is the UV light that causes chemical changes. If the bottle is made of brown glass I don't know how much that protects the spirit but I would suspect atleast some amount. Perhaps you could move the "unprotected" bottles behind the cylinders.

[Baron Rupert Liberis]

I'd agree here the Count, direct sunlight will cause changes in your whisky over time. The amount of change will be dependent on the amount of direct sunlight they receive and the container they are in. A clear glass decanter would possibly be the most significant as the stopper will allow a minute amount of alcohol to evaporate from the decanter**, and permit the maximum amount of harmful UV rays to penetrate and 'spoil' the ingredients. An opaque bottle, or whisky still in the presentation cylinder will be least effected, though the sunlight will cause some warming which won't be particularly beneficial. Also, the sun will bleach the labels as well as the contents over time. Move them out of the sunlight is my advice, or drink them quicker!

** Evaporation of alcohol is a key part to the ageing and maturing of very old single malts. A barrel of Malt laid down 30 years ago will yield far fewer bottles than a similair barrel laid down for only 12 years. You will find that very old whisky's have a much more developed taste due to this and it also accounts for the much higher prices of these older whisky's. Sunlight plays no part of this process and the barrels are kept in the dark for the majority of the ageing process, only being exposed to brief lamplight occassionally as the store is accessed.
Though having then been bottled an old whisky, if unopened, and stored well, will increase in value over the years as the rarity of that particular bottling increases. The value of an unopened bottle of a rare malt will be significantly diminished if the label shows signs of sunbleaching.

[Count Silvio]

Any significant change does not seem to happen over a short period of time as I've had a bottle of rum sit in the sun every morning for a few days and I've not noticed any change in colour or flavour profile. But the sunlight seems to have changed the colour of my Pampero Aniversarios leather pouch. It has become pale brown in the front but there is still some original colour left in the back and insides of the pouch so I suspect some of the other bottles on that same shelf may have been affected somewhat.

Do you think the barrels in the cellar would be affected by normal lamp light?

[Baron Rupert Liberis]

Sun bleaching is unlikely to have a noticeable effect in only a few days, unless it is getting the full force of the summer sun over the whole day. Though a couple of hours a day, over a few weeks will start to show visible effects of bleaching. As for your pouch, you don't state how long it has been exposed to sunlight, but I would guess that this hasn't happened over just a few days.

Barrels in a whisky cellar aren't likely to be effected by electric lamplight for 2 similair reasons - - The lights are only ever switched on for short periods, and low wattage bulbs are usually used - Thrifty people are Scotch Whisky Distillers! Also, very little UV light is given off by electric bulbs, and the whisky is somewhat protected by a nice bit of oak. I don't think anyone has ever conducted experiments to see if whisky would be affected in the barrel by constant exposure to bright electric lighting, but over 30 years there may be a barely noticeable effect, though if the heat given off by the lights wasn't dissipated the difference would be quite marked.
If anyone has got a couple of barrels of newly laid down identical malt whisky, I'd be happy to pay the electric bill for 25 years to see if there is an effect, I'd also be quite happy to invite people to the bottling party too!