Speak to anyone who is considering quitting smoking and giving vaping a go, and along with queries about device-types, juice flavours and shortfill preferences, one question always comes up - just how long does e-liquid last? It’s an important question. After all, you wouldn’t want to stock up on your favourite new e-liquid flavour only to find you don’t use it all before it expires, right?

In this guide, we explore how long e-liquids typically last, why they can turn brown and how quickly you should use vape juice once it’s been opened.

Does e-liquid expire?

Just like with food, drink, pharmaceuticals, medical supplies and an array of other perishable materials, e-liquids can expire, but usually at a much slower rate. For this reason, any shortfill or nic shot you purchase should come with a clear best before date printed either on the bottle or on the outside packaging.

If you were to consume an e-liquid after the expiration date shown, it is highly unlikely that you will experience any adverse effects or suffer any health problems. However, the quality of the vape juice will likely have declined and you may notice a dissipated taste, a change in colour and smell, and - for those e-liquids that contain nicotine - a reduced ‘buzz’. This could prove an issue if you are using a vape as a way of quitting smoking and reducing your nicotine intake gradually.

How long does e-liquid last before going bad?

As discussed above, although e-liquids don’t ‘go bad’ in the same way other perishable goods do, and therefore are unlikely to make you ill if consumed after the recommended expiry date, a drop in quality is certainly likely in e-liquids of all sorts after the best before date.

Interestingly however, the length of time it takes for your vape juice to ‘go off’ may depend on the type of e-liquid you opt for. For example, if you use PG (Propylene Glycol) liquid in your device, you will find your chosen juice will likely have a shelf life of around two years from the point of purchase. On the other hand, if you favour VG (Vegetable Glycerin) liquids, you might notice a much longer shelf life - usually between four and six years. It is worth noting, however, that e-liquids can decline in quality more quickly when open, exposed to air, or if not stored correctly.

How long does e-liquid last once opened?

Even after an e-liquid bottle has been opened and the juice has been exposed to the air, it still should be fine to use until after its expiry date, as long as the bottle (or your vape device) is not open for prolonged periods of time. As previously mentioned, this should be around two years.

However, e-liquids can still decline in quality prematurely if not stored properly. Keeping bottles of juice in direct sunlight or hot temperatures, for example, can see ingredients perish at a faster rate, which will certainly impact your vaping experience. For this reason, always be sure to store e-liquids in a cool, dark place and ideally still in its original packaging.

Why does e-liquid turn brown?

Have you ever picked up a bottle of e-liquid - maybe one you haven’t used for a while - and noticed that it has turned brown? This is quite a common occurrence. It happens when an e-liquid is subjected to prolonged exposure to light and/or heat. Various ingredients in vape juices are sensitive to both of these elements and can start to break down if left exposed for too long.

This happens as a result of oxidation. Nicotine, in particular, is a highly reactive chemical and when exposed to extreme changes in condition, such as sunlight and oxygen exposure, it reacts, turning the whole liquid brown. The easiest way to understand this reaction is to think about what happens to an apple once sliced. As the inside of the apple is left exposed, its white flesh will start to turn brown. A similar process of oxidation happens when vape juices are exposed. The higher nicotine content in your chosen liquid, the more pronounced a potential reaction is likely to be, leading to a darker shade of brown.

While vaping an e-liquid that has turned brown over time is considered perfectly safe, if your vape juice has turned brown before you have even opened the bottle, it may be a good idea to return it and ask for a replacement.