Why do coils get burnt
11 January 2018
In order to avoid burning your coils, it's important to understand what's happening when everything's working well, and then what's happening when things are not going according to plan and the coil is burning out and the liquid is tasting dreadful.
A 'coil' is a piece of metal wire, often coiled, hence the name, and when it's connected to an electrical current it glows. Around the outside of the wire is cotton (but there are other materials) and this cotton sits between the wire and the e-liquid and acts as a 'wick'.
When everything's working well, you press the fire button, the electricity from the battery makes its way to and through your coil and both the coil and the liquid get hot. The heat given off by the coil is absorbed by the surrounding e-liquid, a bit like water in a kettle. The wicking material inside the coil is completely saturated through and the liquid in the coil is heated to the point where it turns into vapour.
With sufficient liquid in the tank, each time you take a puff, there's more liquid to absorb into the coil and the coil doesn't get too hot because the newly absorbed liquid has a slightly cooling effect inside the coil.
When the liquid in the wick has been vapourised, the wick dries out a little, but because you have a tank full of more liquid surrounding the coil, the liquid is constantly replacing itself and re-soaking the wick each time you take a puff.
But problems arise when there's not enough liquid in the wick, or it isn't being absorbed fast enough. When you press the fire button the coil heats up, and if there isn’t much liquid there to take up the heat, it becomes additional heat because there isn't enough liquid to have any kind of cooling effect. This then leads to flavour changes and burning because the liquid still in the wick gets too hot due to this excessive heating.
If you're using cotton coils, this burning results in the production of formaldehyde, which tastes vile and it's bad news to be inhaling it.
When there's insufficient liquid in the wicking in the coil, the wick is directly exposed to the glowing-hot coil and it burns, and once it's burnt it's probably ruined.
How to stop coils burning
1. Prime your coils
If you don’t do this before you vape, especially if you just fill and fire, so-to-speak, you are very likely to completely ruin your coil and it will be of no use thereafter, and money down the drain. Please see our specific article all about priming.
2. Keep your tank topped up
If the amount of liquid in the tank is low, or too low, there's an increased risk that it isn't sufficiently soaking into the wick inside the coil.
Sometimes this doesn't matter too much, but on many coils these days, the liquid has to be at a certain level to reach all the wicking ports (the holes where you can see the wick inside the coil).
If the liquid can't get in, there will be dry areas inside the coil, so take the time and trouble to keep your tank topped up as often as you can. If you notice the flavour going off, check your levels.
3. You may need to use thinner e-liquid
There are two main base ingredients in e-liquid, one is called PG and the other VG. We have covered this subject extensively in our article eliquid blends so we'll summarise it here.
PG is thinner than VG, and therefore it soaks into the wick faster. This means that thicker juices with a higher ratio of VG, say 70% or more, can cause issues, certainly with standard coils but if you have a sub-Ohm coil, they are usually designed for higher VG juice.
If you're using high VG liquid (ie 70% VG) and you're having issues, try opting for a 50/50 blend. Thicker and more viscous e-liquids can clog coils very quickly and cause burning within days of installing a new coil.
Be aware that some coils absorb the liquid faster and better than others. This all depends on their design; the amount of holes, the position and size of them, the material within, etc.
4. Reduce your power
If you have a variable device, one where you can adjust your power level, ie reduce your voltage/wattage, or temperature, be aware that the higher the output, the more liquid you vapourise each time you puff.
This comes back to supply and demand, liquid v coil/wick, if you’re vapourising the liquid at a rate faster than can be replenished into the wick, burning is just around the corner. In fact burning will happen quicker as a result of too much power heating the coil because it's instant excessive heat.
The solution is to just reduce your power setting, especially if you notice the flavour fading.
4a. Stay within the wattage range of your coil
If you look on your coil, there's often a voltage or wattage range written on it, often in very small writing. If it says, for example 10-14W, if you exceed 14W be mindful that you're exceeding the limitations of that particular coil. You're asking it to do a job it wasn't designed for. It's worth checking what other coils are compatible with your device because they will all have different voltage/wattage ranges.
5. Avoid chain vaping
Over-vaping, ie continuous vaping can lead to diminished flavour and a burnt wick because the juice and saturation rate can't keep up with your rate of vaping, and your wick is getting dryer, which is one step away from burning. Stop vaping or slow down. Give your coil time to recover.
To put that another way, constant repetitive puffs prevent the wick from absorbing sufficient liquid, and the cotton nearest to the coil wire can dry out and cause premature burning out of the coil.
6. You may need to change your e-liquid
Some e-liquid flavours have sweeteners that cause major problems with certain coils. This probably relates to the thicker higher VG juices but not always. You may find your coils clogging up very quickly and turning darker and darker in colour. Sometimes these very same liquids will render a coil useless in a day.
7. The same coils with the same liquid won't always last the same amount of time
Please expect some change with the performance of coils due to variances in metals and, for example cotton, which is a natural product and no one piece of cotton is exactly the same as another.
8. Not all coils are right for all users
Some tanks/devices have a number of different coil options to choose from. This is because users often have very particular preferences about their flavour, the heat of the vapour and how much there is of it. It's trial and error finding the right coil for your specific preferences.