In this article...
There are a few reasons that your e-liquid can change colour; If it has been opened and exposed to the air, the age of the e-liquid and what flavour the vape juice is.
Have you ever looked at your favourite bottle of e-liquid and asked yourself why the liquid appears to have changed colour since you bought it?
If the answer is yes you may also have questioned other things about your e-liquid. For example:
- Is your e-liquid "thicker" when the colour is more darker and "waterier" when the e-liquid is clear?
- Is the vape juice flavour affected by this colour change?
- Do you prefer the flavour when the e-liquid has been stored on my shelf at home for a few weeks? Or do you like it straight from the bottle when it was bought?
By now we know one of the big appeals of e-liquid is the personal journey it allows vapers to undertake.
Perception of taste, colour, and even e-juice thickness is a matter of personal opinion. However, we can use a little bit of science to help us understand why your e-liquid changes colour and what impact, if any, this has on the taste of your vape juice. Let's take a look at some Totally Wicked e-liquid and see what happens to them over an extended storage period.
E-liquid Changing Colour
Let us use Red Label Bubblegum 0.6% (6mg/ml) as an example. These are stored in our state of the art laboratory, in a sample library, at room temperature. They each have a date of manufacture (D.O.M), which shows us the age of the e-liquid. The bottles range from freshly made that day, to being over 12 months old.
The freshly made e-liquid will be clear, with a slight tinge of yellow. As the e-liquid matures, the colour will change from a tinge of yellow, light orange, and finally darker orange. If your nicotine strength is higher, the liquid will become even darker over the same period of time.

What Causes E-liquid to Change Colour?
The main reason for the e-liquid colour change is a process caused by oxidation; the gain of oxygen by a substance. It is important to note the colour change due to oxidation is expected and accounted for in the product specification to which Totally Wicked manufacture all e-liquids.
Which substances are being oxidised? The first is nicotine, albeit at a slow rate. When nicotine containing e-liquid is stored at room temperature, the combination of light and air will cause the liquid to darken over a period of time. This darkening can be enhanced by the e-liquid strength. Which is quite logical as higher nicotine concentration in the bottle will result in a darker appearance.
Can My E-liquid Go Off?
No, don't worry. Our laboratory stability tests have shown this nicotine oxidation process to be slow at room temperature, in a variety of e-liquid flavours. The darker e-liquids are still the same quality as the newly produced, clear vape liquid.
The actual flavour can also have an effect on the darkening of the e-liquid. For example, a custard flavour, like Diavlo "The Judge", will darken more significantly. Even at low nicotine strength, due to the presence of specific flavouring ingredients.
Does the E-liquid Thickness Stay the Same?
Yes. The thickness of the e-liquid is the same between the light-coloured and darker colour e-liquid. No chemical processes are occurring when the e-liquid is stored to alter the thickness.
Sure, the diluents in the e-liquid (Propylene Glycol and Vegetable Glycerine) will pick up a little bit of moisture from the air during the maturing process. But not to the extent where you will notice a difference in the thickness of the e-liquid.
What will change is how we perceive the e-liquid colour. The e-liquid stored for over one year simply looks thicker due to the darken colour and the newly manufactured e-liquid looks thinner or "watery", but it actually isn’t.
Steeping E-liquid
Some vapers actually prefer an e-liquid that has matured, that is darker in colour. This process in the vaping world I known as steeping (although this is not technically an accurate phrase for e-liquid).
Other vapers actually perceive no change in flavour from an e-liquid that is Newley made, to one that is ‘steeped’. actually there is debate as to whether steeping actually does anything at all. But some vapers absolutely swear by steeping an e-liquid for weeks before vaping it, especially when it is a dessert flavour.
What we can say, is that even if your e-liquid is slightly darker than you are used to, there is nothing wrong with it. The taste and nicotine hit should be the same. As long as it is less than 24 months after its DOM.
