Food and drink can go bad very easily. Which is why it’s often consumed quite quickly. A bottle of whiskey on the other hand, is usually finished over a longer period of time. Even longer if you don’t really like whiskey but have for some unknown reason, a few bottles on the top shelf of your bookcase. But is whiskey kept for so long because it can last indefinitely or does whiskey go bad eventually and you should refuse that drink from a bottle that’s been sitting on the bookshelf since 1976?
Fortunately, the answer is one you’ll like, although there is a small caveat. Let’s put it this way. Does whiskey go bad? No. Whiskey is pretty hard to damage and can therefore last indefinitely. But does whiskey go bad if you treat it badly? Yes, and there are three things you can do to make it go bad: leave it in direct light, expose it to extreme or fluctuating temperatures or let oxygen get to it. All three things can ruin your whiskey.
Now the first two are easy to avoid. No direct light, no extreme temperatures. Done. But not letting oxygen get to your whiskey is pretty difficult when you want to open your bottle and start drinking it.
But there’s no need to panic and start drinking all your whiskey as soon as possible – at least not without inviting me around to help. You’ve got some time before you need to worry. Plus, there are things you can do to minimize the problem.
Why Whiskey Doesn’t Go Bad
Whiskey doesn’t go bad for two reason. Firstly, because it only ages in casks and secondly because it contains a high level of alcohol.
The longest part of the whiskey making process is the aging or maturation stage where the whiskey is stored in casks for years, sometimes even decades.
During this time, changes in temperature and humidity cause the whiskey to seep into the wood of the barrel and then back out again, picking up all sorts of chemicals (wood sugars, vanillin, lactones, tannins and other compounds) in the process. The more this occurs the more the wood of the barrel transmits different and intricate flavors to the liquid.
Once bottled and away from the wood of the barrels from which it gets 80% of its flavor, the whiskey stops aging.
Its high alcohol content (40% ABV or more) helps preserve it in the bottle by freezing all of its esters, congeners and volatile alcohols and placing them in suspended animation.
That’s why whiskey doesn’t go bad.
This is in contrast with wine that continues to age even in a sealed bottle and within about five years (for most wines, unless they’re of a very high quality) it will pass its expiry date, deteriorate and turn into vinegar.
The upshot of all this is that barring any freak occurrences or you doing something absurd to your bottle, whiskey will last indefinitely.
The Three Things You Can Do to Whiskey to Make It Go Bad
The three things that you can do to whiskey to make it go bad are:
- Leave it in direct light
- Expose it to extreme or fluctuating temperatures
- Let oxygen get to it
Leave It in Direct Light
The ultraviolet rays of direct sunlight will bleach out the color pigments of whiskey and over time discolor it.
Direct light and worse direct sunlight catalyzes chemical reactions in the volatile compounds of the whiskey causing them to break down, so the flavor will, within one to two months, degrade. It will taste much harsher, possibly even of rubber, paint thinner or rotten fruit.
Expose It to Extreme or Fluctuating Temperatures
Slightly warmer and cooler temperatures will not affect your whiskey, but exposure to heat and fluctuating temperatures will.
When whiskey becomes hot it expands, putting it in constant contact with the cork. This will cause it to decay and disintegrate because 40% ABV will do that to a somewhat fragile cork.
Not only does this mean that the cork may crumble unimpressively all over the place when you finally open the bottle, it also means that you will have bits of wood in your whiskey. This is not very nice especially if they are decayed pieces of wood.
More importantly, since the job of a cork is to seal the bottle against oxygen (see next point), a damaged cork means a looser seal and oxygen seeping in. The same is true if there are a lot of temperature fluctuations. With every fluctuation, oxygen can flow into the bottle.
Let Oxygen Get to It
Oxygen leads to oxidation which makes your whiskey go bad. Oxidation is when oxygen binds to one chemical compound turning it into another. When oxygen gets into your whiskey it will change the compounds and the flavor.
Precisely how the flavor of your whiskey will change can’t be predicted. It may be for the better, it may be for the worse. I don’t know the probabilities either way. I do know however, that when you add oxygen to iron you get rusting, when you add oxygen to copper you get corrosion. On that basis it’s not very likely that adding oxygen to whiskey will bring about an improvement.
How to Make Sure Your Whiskey Bottles Don’t Go Bad
Since whiskey only goes bad if you leave it in direct light, expose it to extreme or fluctuating temperatures or let oxygen get to it, it’s easy to prevent by storing it properly. This means storing it in a cool place with no direct light and as few temperature fluctuations as possible.
You also need to store your whiskey bottles standing up. This is because storing them lying down (like heat causing the whiskey to expand) will put the 40% ABV alcohol in constant contact with the cork causing it to decay, disintegrate, become loose and let in oxygen.
On the other hand, leaving your bottles standing up for years means the cork, with no contact with any liquid at all, will completely dry out and again chip, crumble, become loose and let in oxygen. So you need to turn your bottles every so often to ensure the corks don’t dry out.
How to Make Sure Your Opened Whiskey Bottles Don’t Go Bad
Opened whiskey bottles are more problematic because unsurprisingly it’s easier for air to get into places that are unsealed than places with an airtight seal.
Additionally, the more whiskey you drink the more air there will be inside the bottle. This is called the headspace. With a greater air to whiskey ratio, the rate of oxidation will be quicker and the sooner your whiskey will change taste. This just adds insult to injury. Not only is there now less whiskey in your bottle for you to enjoy, there’s more oxygen to ruin the rest of whiskey’s taste faster.
The process can’t be stopped but there are things you can do to extend your whiskey’s life.
Firstly, make sure your bottle is sealed tightly. If the original cork does not seal your bottle well, buy a poly seal cap. If your bottle has a twist on lid you should re-tighten it regularly because they often become lose on their own. There’s also the option of transferring your whiskey into a hermetically sealed glass container.
If you want to use a whiskey decanter, make sure it has an airtight seal and that it does not contain lead. This is because whiskey is drunk and therefore stored over a longer period of time. If your decanter does not have an airtight seal your whiskey will be oxidizing the entire time it’s in there. If your decanter contains lead it will leach into the whiskey and over time reach dangerous levels.
When the volume of whiskey decreases significantly you can transfer it into a smaller bottle, container or decanter to reduce the amount of headspace. This can be done more than once but there will come a time when the amount of whiskey will be so low that the best thing you can do will be to finish it as soon as possible.
How Long Does Whiskey Last Unopened?
Barring any accidents like dropping it and inadvertently opening and drinking it, and if you’ve stored it away from its three natural enemies, an unopened bottle of whiskey will last indefinitely.
But don’t relax just yet. This only means it won’t spoil. We also have to know how long an unopened bottle of whiskey lasts before it evaporates.
Evaporation occurs even when a bottle has an airtight seal because it’s usually not 100% airtight so there’s room for your whiskey to escape. On the other hand, the seal is still somewhat airtight which means that the evaporation will be a slow process (slower even than oxidation) and the closer to 100% airtight the seal is, the slower the evaporation will be.
The minimal amount that evaporates when your whiskey’s in storage for a few years as you make your way through the bottles you’ve already opened and those earlier in the opening order, is tolerable. The problem arises if you’re a collector, storing whiskey for the long term. Evaporation will become noticeable after ten years and after 30 – 40 years of storage the filling level will have drastically decreased.
If your bottle is sealed with a twist on lid the process will be even slower, and if it’s a modern wax dipped bottle, the evaporation will be almost nothing. But if your bottle is sealed with a cork, even if it’s a newer bottle whose corks are meant to seal better making evaporation slower, you’re going to have a problem.
To prevent evaporation, you need to make your bottles more or 100% airtight. You can do this by attaching an additional seal. This can be an additional cap on top of the cork or by dipping your bottle in wax, but these methods can damage the bottle and the underlying seal decreasing their value which defeats the point of your storing them long term instead of drinking them ASAP.
A better solution is to use parafilm. This is a film made from a blend of waxes and polyolefins that’s semi-transparent and flexible. It’s malleable, non-toxic, tasteless, odorless, and self-sealing. You can wrap it around the lid making it airtight and it won’t harm the underlying seal. The only downside is that after some time it becomes brittle and less effective, so it needs replacing every five to seven years.
All Purpose Laboratory Parafilm
How Long Does Whiskey Last Opened?
Opened whiskey will last between six months and two years although this depends on the headspace. An inch or two of headspace won’t have much effect on the whiskey’s taste for at least a year but if three quarters of the bottle is air, the quality will degrade in about a month.
Therefore, it’s best to finish a bottle of whiskey within a few months of opening it so that you can enjoy it at its peak.
This also means that it’s a good idea to calculate the maximum number of bottles to have open at any one time using the only-open-the-number-of-bottles-you-can-finish-in-four-months rule.
How to Tell If Whiskey Has Gone Bad
You’ve somehow gotten hold of a bottle of whiskey whose past treatment history is unknown. It would be a shame to waste something whose flavor may have been perfectly maintained but how can you tell if the whiskey has gone bad?
First look at the bottle and inspect it. If the bottle is leaking or the cork is heavily damaged, then air has probably gotten inside and ruined the flavor of your whiskey. If the cork or the bottle is moldy, things are even worse as your whiskey has been contaminated.
Sediment at the bottom of the bottle is not an indication that the whiskey’s gone bad. Yes, it looks weird and yes, don’t drink the sediment, but all it means is the whiskey was not filtered properly when it was filled from the cask.
Next check the color of the whiskey. If it’s darker than usual and slightly syrupy, some of the watery components may have evaporated. If it’s lighter than usual, this may indicate it has been exposed to too much sunlight. Either way the taste of your whiskey has probably been affected. Obviously, this method only helps if you know what color the particular whiskey you’re looking at is supposed to have.
Check the smell. If it smells ok just not how you expected, then it’s taste may well have been affected. If it smells odd or funny, your whiskey may be contaminated and it’s probably best not to drink it.
Finally, check the taste by taking a small sip. If your whiskey tastes mild, harsh or flat then something has changed its taste. You can still drink it if you wish but I would understand if you didn’t. Either way you should investigate how the mistreatment if this bottle of whiskey happened, who caused it and deal with them appropriately.
If the whiskey has a sour, metallic or strange taste then your whiskey’s probably been contaminated, and you should throw it away.
Does whiskey go bad? No. Whiskey does not continue to age once it’s in the bottle and its high alcohol content helps preserve it. This means an unopened bottle of whiskey can last indefinitely. Does whiskey go bad if you treat it badly? Yes. This means leaving your whiskey in direct light, exposing it to extreme or fluctuating temperatures or letting the oxygen get to it, as this will change the taste of your whiskey.
To make sure your whiskey doesn’t go bad store bottles properly. Make sure your opened whiskey bottles are sealed tight between pours to minimize the increasing oxidation. If you do this your whiskey will last between six months to two years. With one to two inches of headspace the whiskey’s taste will remain unaffected for about a year. But if three quarters of the bottle is air, the quality will degrade in about a month.
Does whiskey go bad? Not unless you treat it badly which you shouldn’t because under normal circumstances whiskey will treat you well.