Speaking extensively, any expiry date you see on a bottle of e-liquid is ultimately an estimation. This is because in the absence of FDA regulation there is no established use-by date for a bottle of juice, but that doesn’t mean that the listed dates are inaccurate.
There are many variables to consider when judging e-liquid longevity. The quality of PG, VG, nicotine and flavoring, the ratios they’re mixed at, and the conditions under which the e-liquid was handled could all affect how long your juice lasts. Usually, the use-by date of bottle of e-juice is likely to be listed as between one and two years.
There are times where E-Liquid will change colors slightly, in this case this is not something unusual and you are most likely safe to vape it. But if your e-liquid color changes significantly, then you should be weary that your E-Liquid has gone bad. E-Liquids will change colors due to the common chemical reaction known as oxidation.
Nicotine itself is a very reactive substance, and can result to your e-liquid to change color when it reacts to other ingredients. This also happens when your e-liquid exposed to air, light, or heat. Oxidation is a natural chemical reaction which does not change the taste or overall vaping experience. Ans this is why your e-liquid is still okay to vape after a slight color change.
High temperatures and light aren’t the only factors that affect the shelf life of your juice, you want to eliminate the amount of air that is constantly being exposed to your e-liquid. So always keep your e-liquid sealed.
Before you panic about the color change in your e-liquid , and throwing “expired” e-liquid in the trash, stop and think about how does the e-liquid smell and how does the e-liquid look.
The best advice is, use the 1 to 2 year expiry date as a guide and not take chances with a juice that may have gone bad. If you do vape it, leaving aside the health and safety side of things, it’ll probably have lost flavor or taken on a foul taste. It’s better to just throw it away.
It is not probably that vaping expired E-Liquid will do any serious harm, but due to the fact that there are no actual studies done on this subject, it is suggested to always make the judgement call. It is always better to be safer than sorry.