What is a vape coil?

How a coil works

A vape coil has two simple components working together: a metal element that heats up when electricity passes through it, and a cotton wick that carries e-liquid to that hot element. Everything else (the metal housing, the threading, the o-rings) is just packaging.

1. E-liquid wicks into cotton

   E-liquid in the tank or pod soaks into cotton wick via the wicking holes on the side of the coil. Capillary action does the work.

2. You press fire or inhale

   Battery sends current through the metal heating element. The element heats up rapidly, typically to 200-300 degrees Celsius.

3. Heat vapourises liquid

   The hot metal vapourises the e-liquid soaked into the cotton in contact with it. Vapour fills the chamber.

4. Air carries vapour to you

   Your inhale draws air through the airflow holes, past the coil, picking up vapour and delivering it through the mouthpiece.

5. Cotton re-wicks

   Between puffs, fresh e-liquid wicks back into the cotton, ready for the next firing.

This is why “dry hits” happen. If the cotton has not re-wicked enough between puffs, or if the wick is too dry from chain vaping, the hot metal heats dry cotton instead of liquid. That burns the cotton itself, giving you the acrid burnt taste.

Coil resistance explained

Every coil has a resistance, measured in ohms (the Ω symbol). This number is printed on the coil and on the box. It determines how much current the battery sends through the coil at a given voltage.

Wire vs mesh coils

Two designs dominate modern coils. Mesh is now standard for sub-ohm; wire is more common in smaller MTL coils.

Coil materials

The metal used in the heating element affects performance, taste and which modes the coil works in.

• Kanthal (FeCrAl): Iron-chromium-aluminium alloy. The most common coil wire. Cheap, durable, reliable. Used in variable wattage mode.
• Nichrome (NiCr): Nickel-chromium alloy. Faster ramp-up than kanthal, slightly better flavour. Used in variable wattage mode.
• Stainless steel (SS): Versatile alloy. Works in both variable wattage and temperature control modes. Many sub-ohm coils use SS mesh.
• Nickel (Ni200): Used only in temperature control mode. Cannot be used in variable wattage. Becoming rare.
• Titanium (Ti): Used only in temperature control mode. Very rare in 2026.
• Cotton wick: Standard. Japanese organic cotton or USA cotton. Sometimes ceramic-wrapped for specific coil designs.

For most UK vapers, you do not need to think about coil material. Whatever your tank uses is probably fine. The exception is if you want temperature control mode, in which case you need nickel, titanium or specific stainless steel coils.

How long coils last

Coil life varies enormously. Most coils last 1-3 weeks of regular use. Some last days, some last a month or more.

Why coils gunk up

Even with perfect care, coils eventually accumulate residue called “gunk” that reduces flavour and life. Understanding what causes it helps you slow it down.

• Sucralose (sweetener): The biggest gunk culprit. Sweetened e-liquids caramelise on the coil at high heat, building up a dark sticky residue. Some “dessert” flavours can kill a coil in 3-4 days.
• Dark colourants: E-liquids with strong colour (brown, red, dark amber) often contain more flavouring concentrate. The concentrate residue also builds up.
• High wattage: Running coils at the top of their range burns flavour molecules onto the coil faster.
• High-VG ratios: Thicker liquid can leave more residue than thin PG-heavy liquid.
• Chain vaping: Keeps the coil hot continuously, accelerating residue baking.

What to do about it: choose lighter, less-sweetened flavours where possible (menthol, fruit rather than dessert), run wattage at the middle of the recommended range, take short pauses between puffs, and accept that coils are consumables.

Replacing a coil correctly

1. Empty the tank

   Most tanks need to be empty before changing the coil. Pour remaining e-liquid into a clean container or tissue.

2. Unscrew or remove the old coil

   Twist or pull the old coil out. Note how it sits. Inspect the o-rings while you are in there.

3. Prime the new coil

   Apply 4-6 drops of e-liquid directly to each cotton wicking hole on the new coil. See our guide on priming a coil.

4. Install and refill

   Screw or click the primed coil into the tank. Refill with e-liquid.

5. Wait 5-10 minutes

   The wick needs time to fully saturate. Skipping this is the most common cause of burnt first puffs on new coils.

6. Start at lower wattage

   First few puffs at the bottom of the coil's recommended range. Work up to your normal wattage over a minute.

The bottom line