Does Whiskey Go Bad in The Sun? Everything You Need to Know

On the one hand, whiskey is a strong drink that’s pretty hard to damage. On the other hand, lots of things go bad in the sun so it’s reasonable to wonder whether whiskey is one of them. That’s why I decided to look into whether whiskey goes bad in the sun and here’s what I found.

Whiskey left in the sun for a long period of time will go bad within one or two months. It will also evaporate quicker and become oxidized sooner than usual. However, whiskey left in the sun for a short period of time can actually taste better.

In the rest of this article, I’ll explain the different ways exposure to the sun can damage your whiskey and the various things you can do about it. We’ll also look in more detail at how to use short periods of exposure to the sun to make your whiskey taste better.

An upturned bottle of whiskey in the sun

Why Whiskey Left in The Sun Long-Term Goes Bad

As mentioned, whiskey left in the sun for a long period of time will go bad within one or two months. That’s because the sun’s ultraviolet rays create a chemical reaction in the volatile compounds of the whiskey which causes them to break down, and the flavor to degrade. The whiskey will taste much harsher, possibly even of rubber, paint thinner or rotten fruit.

Additionally, the sun’s ultraviolet rays will bleach out the color pigments of the whiskey and over time discolor it. In other words, the beautiful golden color of your whiskey will be lost too.

(As a side note, I wrote an article that explains all the things that can make whiskey go bad, which you can find here.)

How To Stop Whiskey Going Bad in The Sun

Obviously, the easiest way to stop your whiskey going bad in the sun is to store it where it won’t be exposed to its light. But if that’s inconvenient, or you just don’t want to shove your highly valued whiskey into some cupboard where it can’t be easily seen or accessed, then to ensure your whiskey doesn’t become damaged by the sun, you’ll need to do something to protect it from its light.

One thing you can do is to store your whiskey in a glass bottle with a dark color. That’s because glass bottles with a dark color allow less light to pass through them than clear bottles. (Which is why some whiskey bottles are made from a dark colored glass.)

The problem with this approach is that some sunlight is let in (depending on the exact bottle and its color) so you’re not so much protecting your whiskey as delaying its expiration. However, while that means this method certainly won’t protect your whiskey over the long-term, it might be a good enough solution if you’re only planning on storing your whiskey for a short time while you drink it over a few months.

Another way to protect your whiskey from the rays of the sun is to store it in the box it comes in. However, once again the amount of protection this gives your whiskey will vary depending on the box, so it too may not be a long-term solution.

The best way to keep your whiskey in the sun without it becoming damaged is by storing it behind windows or glass with a UV-blocking coating. Of course, the problem with this approach is that it’s more expensive, but if you’re planning on displaying your whiskey or whiskeys this way long-term, it will certainly be worth it.

Bottles of whiskey in a glass box with ultra violet coating

Whiskey Left in The Sun Evaporates & Oxidizes Faster

So far we’ve seen that whiskey goes bad in the sun because its ultraviolet rays degrade its flavors and color, but whiskey can also go bad in the sun when its heat causes the whiskey to evaporate faster and oxidize sooner.

Why Whiskey Left in The Sun Evaporates Faster

It may surprise you to learn that whiskey is always evaporating from the bottle. That’s because although many seals are airtight, they’re not 100% airtight, which means there’s still some room for the whiskey to escape.

Fortunately, evaporation is slow, and the amount of whiskey lost to it is minimal, so it usually only becomes a problem if you’re planning on storing your whiskey for many years – it takes about 10 years for the amount lost to be noticeable and 30 – 40 years for it to be significant. Which is why for most people, who aren’t storing their whiskey for anywhere near as long, it’s not worth doing anything about.

However, if you store your whiskey in the sun, the heat will cause it to evaporate faster than usual.

Why Whiskey Left in The Sun Oxidizes Sooner

Oxidation is when oxygen binds to one chemical compound and turns it into another, and in whiskey that means binding to one flavor compound and turning it into another. Whiskey that’s gone bad in this way is not dangerous to drink – it’s still drinkable, but it does mean that it won’t taste the way it’s supposed to so it’s something to be avoided.

Oxidation starts as soon as your whiskey becomes exposed to air – which is usually when you first open the bottle, but it doesn’t change the flavors of your whiskey immediately. That usually takes anywhere from six months to two years depending on how much air gets into the bottle.

However, if you store your whiskey in the sun, the heat will cause it to oxidize sooner. That’s because whiskey expands when it becomes hot which in a fuller bottle, brings it into contact with the cork. Whiskey has a high alcohol content level (between 40% – 68%ABV) which is more than enough to damage any cork that it’s in prolonged contact with.

And a damaged cork means a looser cork that lets more air into the bottle, which speeds up the process of oxidation.

How To Stop Whiskey Evaporating & Oxidizing in The Sun

To stop the heat of the sun from causing your whiskey to evaporate faster and oxidize sooner, you need to store it in a cool temperature. 15°-20°C or 59°-68°F is best.

If you’re already storing your whiskey out of the sun so that it’s ultraviolet rays won’t make it go bad, then it will automatically be out of its heat too, but if you’re keeping your whiskey in the sun and using something to protect it from its light, then you also need to ensure that you don’t forget to protect it from its heat too.

Of course, there’s more to storing your whiskey properly as you need to protect it from things other than the sun that can damage it too. Which is why I have written a more detailed article about how to store whiskey, which you can find here.

Why Whiskey Left in The Sun Short-Term Tastes Better

2 glasses of whiskey on a table in the sun

Although the sun is one of the few things that can damage whiskey, being left in the sun for a short period of time will actually make your whiskey taste better, for the following reason.

As mentioned, whiskey has a high alcohol content level. This causes a problem as it keeps many of the whiskey’s flavors closed up and overpowers those that aren’t, which is why many whiskey drinkers try to reduce its impact.

One way they do this is by accelerating the process of whiskey evaporating. Although as we’ve seen, this is a problem in the long term, in the short term it’s actually beneficial. That’s because alcohol has a lower boiling point than water, which means that during evaporation more alcohol will be removed than whiskey.

This is why when drinking whiskey, it’s important to use a nosing glass. Their wide bowl leaves more space for air to get to the whiskey which helps the alcohol evaporate. It’s also why when a glass of whiskey is first poured it should be left to sit untouched anywhere from a few minutes to a couple of hours, so that even more air can get to it and even more alcohol can evaporate.

And of course, letting your glass of whiskey sit in the sun during that time will accelerate the process of evaporation even more. And the more you reduce the amount of alcohol in your whiskey, the less it will dominate your drink and the more of its flavors will open up, making your whiskey taste better.

Josh Mitchell

I'm Josh Mitchell. I love whiskey and am working on increasing my whiskey tasting abilities and my collection.

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