Coil resistance and e-liquid ratio explained: getting the setup right

Coil resistance and e-liquid ratio are the two specs that matter most when setting up a device, and they're closely linked. Get them right together and a pod or tank performs the way it was designed to. Mismatch them and you'll typically end up with either weak, harsh flavour or a leaking, gurgling pod, even with a coil that's otherwise perfectly compatible. This guide is a good starting point if you haven't read our other two references yet: pod and coil compatibility and why pods leak and how to fix it.

Sub-ohm versus above-1-ohm coils

"Sub-ohm" simply means a coil with resistance below 1.0 ohm. Lower resistance allows more current to flow at a given voltage, which generates more heat and vapour, so sub-ohm coils are built for direct-to-lung (DTL) vaping: a loose, lung-filling draw similar to breathing normally. Coils above 1.0 ohm restrict current more, run at lower wattage, and are built for mouth-to-lung (MTL) vaping: a tighter draw pulled into the mouth first, closer to drawing on a cigarette. Neither is objectively better; they suit different vaping styles and different e-liquids.

Why VG/PG ratio needs to match your device

VG (vegetable glycerine) is thick and produces dense vapour. PG (propylene glycol) is thin, carries flavour well and produces a stronger throat hit at a given nicotine strength. Sub-ohm DTL coils have larger wicking ports and higher power, so they can pull thicker, high-VG liquid through efficiently. MTL coils have smaller wicking ports and run at lower power, so they're built around thinner, higher-PG liquid that saturates the wick without flooding it. Put high-VG liquid in a low-power MTL pod and, in our view, you're one of the more likely causes of a pod that leaks or gurgles despite being set up correctly in every other respect.

Nicotine salts and higher-resistance coils

Nicotine salt e-liquids use a different chemical form of nicotine that's smoother at higher strengths than standard "freebase" nicotine. Because they're typically vaped at higher strengths and lower wattages, nic salts are most often paired with higher- resistance MTL coils in pod systems, rather than sub-ohm DTL setups where a high nicotine strength would usually feel too harsh. UK- regulated e-liquid, including nic salts, is capped at 20mg/ml nicotine strength under the Tobacco and Related Products Regulations (TRPR). Bottles of nicotine-containing e-liquid are limited to 10ml, and any single tank, pod or cartridge holding nicotine e-liquid is limited to 2ml capacity, whether refillable or pre-filled.

Simple compatibility table

These are general, widely-used pairings rather than fixed rules; check the coil packaging and pod manufacturer's guidance for your specific device, since the exact recommended range can vary between manufacturers. According to the NHS, vaping is not risk- free but is substantially less harmful than smoking for adults who already smoke, and switching from disposables to a refillable pod or tank system is now the main route into vaping since single-use disposable vapes became illegal to sell across the UK from 1 June 2025.

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