Does Tonic Water Go Bad?
Yes, tonic water can lose its quality over time, though it rarely becomes unsafe to drink. While it won't spoil in the same way perishable foods do, its fizz, flavor, and carbonation will diminish.
The shelf life of tonic water depends heavily on storage. Unopened bottles stored in a cool, dark place or refrigerator can remain safe for consumption for up to a year, often exceeding the "best before" date. [Several sources](https://www.mixlycocktailco.com/blogs/news/does-tonic-water-go-bad, https://www.stilltasty.com/fooditems/index/18537, https://www.quora.com/Does-tonic-water-go-bad-Can-you-drink-it-after-it-expires) suggest a shelf life of 9 months to a year even after the expiration date for unopened bottles. Heat and humidity can negatively affect its quality, causing a loss of fizz and flavor. Source
Once opened, the carbonation will escape more quickly, affecting the taste. Refrigeration helps slow this process, but it is best to consume opened tonic water within a few days.
Effects of Expiry
While consuming expired tonic water is unlikely to cause immediate health problems, the taste experience will be compromised. The fizz will lessen, and the flavor might become dull or slightly off. Source Always check the "best before" date and prioritize using the tonic water within the recommended timeframe for optimal enjoyment. Source
