If you need some tonic water for your cocktails, but you’ve had your tonic water stored away for a pretty long time, you may be wondering: Does tonic water go bad? How long does it last?
Here’s the deal: tonic water lasts one year past the best-by date if unopened. As soon as the bottle is opened, it will last 3-5 days if stored correctly.
How To Tell If Tonic Water Has Gone Bad

Tonic water doesn’t actually go bad and becomes unsafe to drink. Instead, it will lose its quality over time.
Look out for any contaminants that may have entered the bottle. If so, get rid of it. If you notice a change in smell or any discolorations in your tonic water, it’s best to discard it. Lastly, you should give your tonic water a taste. If you’re satisfied, hold onto it. If not, you can throw it out for quality purposes.
Storing Tonic Water

To keep it at its best quality, store your tonic water in the fridge or pantry, so long as your tonic water is in a dry environment away from sunlight and sources of heat.
Once you open your bottle of tonic water, the fridge is the best place to store it. Make sure it is tightly sealed.
Refrigerating your tonic water isn’t necessary if you plan on using it immediately. However, the fridge is the way to go if you’d like to store it for a few more days.
How Long Does Tonic Water Last?

Tonic water comes with a best-by date on the label, but it will stay fresher for longer than the date provided. If the tonic water is unopened, it could last about one year past the best-by date, whether it’s kept in the pantry or fridge.
However, as soon as you open your tonic water, it will start to lose its quality and bubbliness faster. At room temperature, it will be good for 1-2 days. In the fridge, it retains its freshness for 3-5 days.
After a few days of being exposed to air, it will lose its carbonation. Tonic water will still be safe to consume, but it will be flat and watery. You may decide to toss it out for quality reasons.
What Makes Tonic Water?

Tonic water is carbonated water infused with quinine. Quinine comes from the bark of the cinchona tree, usually found in South America. This is what gives the tonic water its bitter taste.
The Verdict On Tonic Water
The first patent for tonic water was awarded to Erasmus Bond in 1858. Tonic water still remains a popular drink today.
In order to ensure the best quality of your tonic water, make sure it is stored properly and sealed tightly.
Tonic water may not become unsafe to drink; however, it may lose the taste and bubbliness that you’re looking for. If that happens, getting rid of it for quality purposes is a good idea. Overall, enjoy your tonic water quickly to retain its freshness.