Sweeteners in e-liquid: why your sweetest flavours kill coils

The most common sweetener in e-liquid is sucralose, the same one found in many sugar-free drinks. It is around 600 times sweeter than sugar, so a tiny amount goes a long way. Ethyl maltol is another regular, adding a candyfloss-style sweetness and rounding out fruit and dessert flavours.

Neither is sugar, and e-liquid does not contain table sugar. But sweetness has become a big part of what makes bar-style and candy flavours so popular, so these ingredients turn up in a lot of bottles. Ingredients are listed on UK labels, though sweeteners sometimes sit under the general term flavourings.

Your coil heats to well above the temperature at which sucralose starts breaking down. Instead of vaporising cleanly like PG and VG, some of it chars and sticks to the coil and cotton. Over a few days that builds into a dark crust, often called gunk.

Gunk does two things. It insulates the coil, so flavour fades. And it clogs the cotton, so liquid wicks more slowly, which leads to the dreaded burnt hit. Heavier sweetening, higher power and chain vaping all speed it up. That is why a candy liquid might finish a coil in days while a menthol lets the same coil run for a week or more.

Sweetness levels are rarely printed on the bottle, so you have to read the clues. Flavour descriptions using words like candy, sweets, sherbet, cotton candy, bubblegum or custard almost always mean a generous dose of sweetener. Bar-style ranges also lean sweet by design.

Tobacco, menthol, mint and many fresh or sour fruit liquids tend to be lighter on sweetener. Some brands sell no-added-sweetener ranges, which is worth checking in the description. If a liquid leaves a sweet film on your lips, it is a heavy one, and your coil will notice. Compare sweets and candy with tobacco to see the difference in descriptions.

You do not have to give up your favourite candy liquid. A few habits make a real difference to how long each coil survives a sweet diet. Lower power is the biggest one: less heat means less charring. Stay in the lower half of the watt range printed on your coil.

Leaving a few seconds between puffs gives the cotton time to resaturate. Rotating in a less sweet liquid for a day or two between sweet ones slows the build-up. And replacing coils at the first hint of fading flavour is cheaper than suffering a week of muted vaping. Fresh coils for most kits are in coils, and buying them in packs works out cheaper per coil than buying singles.

Sweeteners get blamed for a lot in vaping, sometimes fairly and sometimes not. The idea that sweet liquid contains sugar is the most common confusion, followed closely by the belief that all fruit flavours are equally hard on coils.

Flip the cards for the facts. If coil life is a constant headache, our guide to e-liquid for MTL pods covers ratios and strengths that keep small coils happier, which helps alongside picking less sweet flavours. Thin liquid that wicks quickly gives sweetener less time to scorch on a dry patch of cotton, so the two habits work well together.

Here is a pattern we see all the time. A vaper's coils used to last about ten days. They switched to a sherbet candy liquid a month ago and now each coil turns dark and tastes burnt after about three days, even though the pod kit, the wattage and the amount they vape have not changed at all.

What is the most likely explanation, and what would actually help? Pick the answer that fits the facts best. The giveaway is timing: only one thing changed a month ago, and the coils started dying at exactly the same moment.