Whiskey aficionados are well known for collecting many types of whiskeys. They will often have shelves full of interesting whiskeys dating back many years. Opening one of these bottles is a special treat that they get to enjoy with family and friends.
But how long does whiskey last in an unopened bottle?
Does opening the bottle shorten its lifespan or change its flavour?
Theoretically, an unopened bottle of whiskey will last forever if kept in the right conditions. Distilled spirits don’t spoil as wine or beer does. However, this is somewhat dependent upon how the whiskey is stored.
If an unopened bottle of whiskey is exposed to UV light (sunlight) for long periods, it can cause organic compounds in the whiskey to undergo catalysing reactions that cause them to break down. Some of these organic compounds are responsible for the wonderful flavour and aroma of whiskey. Once they break down, the whiskey loses some of its flavours and aroma.
Exposure to UV light may even cause free radicals to develop in the whiskey, which can tarnish the flavour of the whiskey. Eventually, exposure to sunlight can cause evaporation, reducing the amount of whiskey remaining in the bottle and changing its flavour even more. It is also common for whiskey exposed to sunlight to lose its colour.
How long does an opened bottle of whiskey last?
Once you have opened a bottle of whiskey the alcohol that is present will begin to slowly evaporate, which will make it taste smoother. Having a smoother tasting whiskey is usually a good thing and the reason why people often decant a newly opened bottle of whiskey.
An opened bottle of whiskey will also begin to oxidise. This is the process that occurs when oxygen interacts with the compounds within the whiskey. This can have an unpredictable effect on a spirit, sometimes making it taste better, other times making it taste worse.
The amount of time that an opened bottle of whiskey will last can vary based upon the air to whiskey ratio in the bottle. That’s because the oxidisation process will speed up when the ratio of oxygen to whiskey increases. Most experts believe that a half-filled bottle of open whiskey will last between 1 to 2 years. A quarter filled bottle may only last between 3 to 4 months.
The impact of oxidisation on whiskey is the reason why many collectors will transfer their open whiskey into smaller containers, so the ratio of oxygen to whiskey remains lower. Doing this can add many months to the lifespan of an opened bottle of whiskey.
Does it age in the bottle?
Whiskey is different to wine, in that it does not age while in the bottle. A whiskey that was aged for 12 years in a cask then placed into a bottle, remains a 12 year old whiskey — regardless of how many years later you open it. The whiskey will not improve or deteriorate while in the bottle as long as it is kept in ideal conditions.
How to tell if whiskey has gone bad
It’s usually quite obvious if a whiskey has gone bad. You may notice the following tell tale signs:
The colour has changed
It smells or tastes bad
There is mould or debris in the bottom of the bottle
If an old whiskey looks or smells bad, discard it immediately. If it looks and smells fine, taste a small amount to determine if it is safe to drink. If it has a milder taste than usual, that is fine. But if it has a sour, metallic, or other strange taste, discard it.
Tips for keeping open bottles of whisky
Here are a few simple tips that will help you maximise the length of time that your opened bottles of whiskey will last.
Keep your whiskey cool – Whiskey should be kept at or below room temperature (ideally 15 to 20 degrees Celsius and no higher than 24 degrees Celsius). The best places to store whiskey to ensure it doesn’t get too hot include the bottom shelf of the pantry, in the basement, or in a root cellar. Avoid letting your whiskey heat up and cool down repeatedly. If your whiskey in a very cold room, you might notice it becomes cloudy. This is fine as the cloudiness will disappear when it returns to room temperature.
Keep it away from light – As mentioned earlier, light can damage both unopened and opened bottles of whiskey. Keep your whiskey out of direct sunlight by placing it in a dark room, liquor cabinet, or box.
Store bottles upright – Whiskey bottles should be stored upright as the spirit can gradually eat away at the cork, allowing air into the bottle.
Limit the amount of oxygen that reaches your whiskey – Oxidisation is the main killer of opened bottles of whiskey. Either invest in a vacuum sealer for your whiskey bottles or transfer your whiskey into smaller bottles once opened. Some whiskey aficionados use a product called Private Preserve to extend the lifespan of their whiskeys by slowing the oxidisation process.
Drink it! – Finally, if you really want to ensure that your open bottle of whiskey doesn’t go bad, you can always drink it (in moderation of course).