In order to avoid burning your coils, it helps to fully understand what's happening when everything's working just fine, 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.
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 the water in a kettle. The wicking 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 on the wicking 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 and the coil heats up, there isn’t much liquid there to take up the heat, and it becomes additional heat as there isn't enough liquid to have any kind of cooling effect, in other words, the temperature of the coil increases abnormally. This then leads to horrid things happening because the liquid still in the wick gets too hot, “overcooked,” as it's heated up excessively.
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 very probably ruined.
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.
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.
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 often designed for higher VG juice.
Just be aware that some coils, depending on their design, ie amount of holes, the position of them etc, wick better than others.
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.
If you look on your coil, there's usually 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.
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.
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!
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