Coking on the e-cigarette - burnt flavour explained

In vaping terms, burning means that the cotton in the coil burns partially or completely because it is too dry at the moment of vapourisation. The heating coil then reaches temperatures at which it is no longer the e-liquid but the cotton itself that chars. The result is a characteristic burnt taste, often accompanied by a scratchy throat and a dark discolouration of the cotton.

It is important to distinguish between this and actual burning: a brief, slightly dry puff (‘dry hit’) can occur once if the atomiser has not been fully primed after refilling. Genuine charring, on the other hand, persists, even after a break and with a full tank. Once the cotton has charred, the coil cannot be saved – the burnt taste remains, no matter how much e-liquid you top up. The only solution is to replace the atomiser head or, in the case of self-built atomisers, to re-wrap it with fresh cotton.

A coil always burns for the same reason: the cotton cannot supply the e-liquid fast enough for the heating wire to vapourise. The specific causes vary.

Too high a wattage

Every atomiser head is designed for a specific power range, usually printed on the coil itself (e.g. 20–30 W for a 1.2-ohm coil). If you go significantly above this, you produce more vapour than the cotton can supply – resulting in burnt-tasting puffs.

Chaining puffs without a break

If you take lots of puffs in quick succession, the cotton doesn’t have time to reabsorb the e-liquid. Particularly with sub-ohm setups that produce a lot of vapour, just 3–4 puffs in a row are often enough to dry out the coil.

Incorrect VG/PG ratio

Very viscous e-liquids with 80% or more VG flow more slowly through the wicking channels. In small MTL coils with tight wicks, this quickly leads to the wick burning. Pod systems and small atomisers usually require a more balanced 50/50 or 60/40 ratio.

Empty tank or pod

If the e-liquid level drops below the wicking holes, the cotton draws in air instead of e-liquid – a classic cause of burning.

With a few simple routines, you can significantly extend the life of your coils and reliably avoid a burnt taste.

• Keep the wattage within the recommended range: start at the lower end and work your way up slowly. As soon as the flavour changes, reduce the wattage immediately.
• Break in a new coil properly: After inserting it, wait 5–10 minutes and manually saturate the wicking holes with a few drops of e-liquid (priming). Take the first few puffs at a low power setting.
• Keep an eye on the e-liquid level: Never let it drop below the minimum. Tanks can run low quickly, especially when stored horizontally in a car or a bag.
• Choose e-liquid suitable for your setup: Pod systems and MTL coils work best with 50/50 e-liquids or nicotine salt; sub-ohm vapes can handle 70/30 or higher.
• Take breaks: Wait 5–10 seconds between puffs to allow the cotton to soak up the e-liquid.
• Change the coil in good time: depending on usage, a coil head lasts 1–3 weeks. A bitter taste, less vapour or a scratchy sensation are warning signs.

Can I salvage a burnt coil?

No. Once the cotton has burnt, the burnt taste will remain permanently. You can still use the coil, but you won’t get clean vapour anymore. It’s better to replace it straight away.

How can I tell if the cotton has burnt?

Most clearly by the taste: bitter, smoky, slightly woody. Visually, when the coil is unscrewed, you’ll see dark brown to black patches on the cotton. Fresh cotton is light beige.

Why does my new coil burn immediately?

This is typically due to a lack of priming. New atomiser heads must be soaked in e-liquid before the first puff and left to soak for 5–10 minutes before you start vaping. Otherwise, the dry cotton will burn during the first vape.

Is burning related to the nicotine content?

Indirectly. Nicotine itself does not burn, but e-liquids with a high nicotine salt content are usually used in pod systems with low wattage. Anyone vaping such e-liquids in a sub-ohm setup risks burning out coils quickly.

A burnt taste is almost always a sign that the wattage, e-liquid and coil are not compatible, or that the atomiser head has reached the end of its life. Pay attention to the recommended power range, prime new coils correctly and choose a suitable VG/PG ratio – then burnt puffs will remain the exception. In our selection of atomiser heads and coils, you’ll find suitable replacement coils for popular tanks and pod systems, and with our e-liquids, you can experiment with the various mix ratios.