How Long Before Cognac Whisky And Other Liquor Goes Bad

I am sure you have heard that the longer a bottle of cognac is kept, it is better. The word “better” is subjective and depends on who you talk to.


If you google, below is what you can find about UNOPENED cognac and whisky:

  • Once a cognac or whisky is bottled, it stops aging. Therefore, technically the cognac or whisky will stay the same AS LONG AS IT IS NOT OPENED.
  • Keep the bottles upright to prevent the liquid from touching the cap, which may cause corrosion that affects flavor and quality.
  • However, an unopened bottle may change color and aesthetic. Steven DeAngelo, founder of Brooklyn distillery Greenhook Ginsmiths, tells SELF, “What could happen over an extended period of time is that solids will fall out of suspension and the spirit will develop a cloudy look, but that doesn’t mean there’s anything wrong with the product.”
  • When liquor is exposed to daylight over a long period of time, it can lose colors. For liquor, color changes are indicative of flavor changes. Similar to that, temperature changes can degrade an organic molecule called “terpene,” which alters the liquor’s flavor.

So basically if you keep an unopened bottle of cognac or whisky away from sunlight and store it in a cool place, the taste should remain the same from the day it was bottled.

However, I can tell you that an old bottle cognac, say Hennessy VSOP that was bought 10 years ago can taste 100 times better than a bottle which you can buy at the store today. Wny? My guesses are as follows:

  1. Somehow the alcohol in the bottle managed to evaporate despite it being unopened and therefore making it smoother to drink. Therefore, people like me love it as it is smoother. However, because there is less alcohol, one won’t get high or drunk and in this instance, a person may say the drink is lousy, haha.
  2. Most of the cognacs are blended and therefore each batch bottled taste different!
  3. Also the grapes produced every year is different. With climate change and use of different chemicals compounds (pesticides), I am sure today’s grape taste different from the pass.

Now, I have something to share with you that may surprise you. A bottle of Hennessy XO or Remy Martin XO bought in Europe (e.g. London Heathrow Airport Duty Free) taste better than the same Hennessy/Remy Martin XO we can buy in KL (Eraman Duty Free or AirAsia Duty Free or Jaya Grocer)!!! So, if you ever go to Europe, get your cognacs there instead of buying it at Eraman Duty Free. Having said this, if you are are flying Emirates, you can buy cognacs at Dubai Duty Free too as the liquor there are still better than what we get in KL somehow.

Below is what you can find about OPENED cognac and whisky:

  • Air exposure can lead to oxidation of liquor that affects its flavor.
  • To minimize this effect, keep liquor in the tightest, smallest sized bottle that you have. If you only have 1/4 of a large bottle left, consider pouring the contents into a smaller bottle to minimize the surface area exposed to oxygen.

In respect to the above, once you open a liquor bottle, best you finish it as soon as possible after you open it because it might not stay good forever.


When we say a particular whisky or cognac is good, generally we mean the taste and smoothness.

So what is bad? Let me tell you my experiences:

Once I went to my friend’s place and he offered me the Nikka 12 Years Old but I saw he had an opened Martell VSOP. I tell you, today’s Martell VSOP (not the new Red Barrel) taste lousy but the older Martell VSOP are very nice. So I asked for the Martell VSOP instead and when I took a sip, it tasted horrible!

You see,  the bottle of Martell VSOP Cognac was less than a quarter full and was opened 3 years ago! Therefore there was more air in the bottle compared to the liquid alcohol. Remember I mentioned earlier that – Air exposure can lead to oxidation of liquor that affects its flavor.

In addition to the above, there was another time I experienced how a good bottle of cognac can turn “bad”. Few years back, my late grandfather took a bottle of opened Louis XIII (today a bottle cost close or more than RM10K) which he has kept for sometime to a family dinner. It was also less than a quarter full. So I took a sip and to my horror it tasted like Chinese Kung Fu medicine!!! Immediately I switched to the cheaper Hennessy XO which is also my favorite, haha.

FYI, I have tried Louis XIII many times and one particular experience with it has given me lasting fond memories. I still can remember the first time I tried Louis XIII more than 20 years ago where my dad opened a bottle during a family gathering. That time I was young and would mix coke to any brandy, haha. When my grandfather found out I mixed coke with Louis XIII, he scolded me – I miss my grandfather as he is a cognac lover and sometimes when we have dinner together I will drink a couple glasses of cognac with him.

Now, technically cognac or whisky bottles which are opened for years are still alcohol and therefore germs cannot survive inside in to turn it “bad” to harm you BUT the taste will definitely change because of the air inside the bottle. Having said this, I recommend that you do not drink anything that is horrible to you as nothing good will come out of it.

In respect to the above paragraphs, I have learned that an opened cognac taste will change with time, more so if there is more air compared to liquid in the bottle. Nowadays, I will try to finish an opened bottle of cognac asap and not open many different types of cognacs or whiskies at anyone time.

If you have an opened bottle, you should pour it to a smaller bottle so that there is less air to mix with the alcohol. But then again, best you finish it asap.

Click here to my Spirits Page to see my collection of liquor in KL and Melbourne.

As for wine, it is said the taste will be maintained as long as it is not opened and properly stored. For me, once I open a bottle of wine, max I will keep it for 2 days only. And read the ingredients used to make the wine and you be shocked to learn what you are drinking, hahaha.

As for beer, refer to the expiry date on the bottle.