E-Liquids 101: What Are They?

You'll see it called e-liquid, vape juice, vape liquid or e-juice depending on the brand, but they're all the same product under different names. It's the liquid that goes into your vape kit and turns into vapour when the coil heats it up.

What are e-liquids? All UK e-liquid start with the same four base ingredients: PG, VG, flavourings and nicotine. What changes from bottle to bottle is the nicotine type, the strength and the VG/PG ratio. A 20mg nic salt in a pod kit won't feel anything like a 3mg shortfill running through a sub-ohm tank. Both sit on the same shelf, but they're made for completely different setups.

Four Types of E-Liquid

Nic Salts

Most people switching from cigarettes to vaping end up starting with nic salts. They use a different form of nicotine that's been processed to feel smoother, so 20mg won't burn your throat the way freebase at the same strength would. They come in 10ml bottles, usually 10mg or 20mg, and you'll find them all in the nic salt e-liquids section.

They're built for pod kits and MTL tanks running a 50/50 VG/PG ratio. The nicotine hits your bloodstream faster than freebase too, so you don't need as many puffs to sort a craving.

Freebase E-Liquids

Before nic salts came along, freebase was all there was, and it's still the most widely sold type of e-liquid in the UK. The throat hit is sharper and harsher at the same mg level compared to nic salts, and most freebase liquids sit between 3mg and 12mg. You'll find them in 50/50 ratios for pod kits or 70/30 for bigger tanks.

Where freebase really helps is if you want to step down your nicotine gradually. Strengths go from 18mg right down to 0mg with smaller gaps between each level. You've got more room to reduce at your own pace than you do with nic salts.

Shortfills

If you vape a lot, 10ml bottles add up fast and shortfills are the way around it. They're bigger bottles (50ml or 100ml) sold with no nicotine, and there's space left in the top for you to add a nic shot to bring the strength up to about 3mg.

Nearly all shortfills use a 70/30 VG/PG ratio because they're built for sub-ohm tanks and higher wattage kits. You won't get strong nicotine from them once mixed, but the cost per ml is much lower than buying 10ml bottles. The shortfill e-liquids guide on our blog walks through the mixing process and which nic shot strengths to pick.

Longfills

Longfills are concentrated flavour shots in a bigger bottle with room to add your own VG, PG and nic shots. You're mixing more than you would with a shortfill, but you get full control over the final ratio and strength. They're less common than the other three types in UK shops, but vapers who like to tweak their setup tend to prefer them for the flexibility.

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E-Liquid Strengths Explained

UK law caps nicotine at 20mg/ml (Maximum allowed in UK) and that's the highest you'll find in any UK bottle. From there it goes all the way down to 0mg for people who've dropped nicotine altogether. The mg number on the bottle tells you the concentration, but 20mg in nic salt and 20mg in freebase don't feel the same at all. The nicotine type and the kit you're using both change how that number hits.

Nic salts at 20mg feel smoother than freebase at 20mg because of how the nicotine's processed. Sub-ohm kits also push out a lot more vapour with every puff. Even 3mg in a sub-ohm tank gives you more total nicotine per draw than 3mg in a pod kit. Sub-ohm vapers stick to lower strengths for that reason.

Our nic salt strengths guide covers the 5mg, 10mg and 20mg options in more detail if you're choosing between them.

VG/PG Ratios and What They Mean

Every bottle has a ratio printed on it showing the split between vegetable glycerin (VG) and propylene glycol (PG). VG is what makes the vapour thick and smooth, while PG carries the flavour and adds the throat hit.

Put 70/30 liquid in a pod kit and the coils can't wick fast enough. You'll end up with dry hits or a burnt taste that ruins the coil. Go the other way and put 50/50 in a sub-ohm tank, and the thin liquid floods the coil and spits back at you. Getting the wrong ratio for your kit is one of the most common mistakes people make.

The VG vs PG guide on our blog breaks down the differences in full if you want to dig into which ratio suits your setup.

Matching E-Liquid to Your Kit

Get this pairing wrong and you'll either burn through coils or get a mouthful of spitting liquid. The kit you're using decides what liquid you can actually run.

The coils in pod kits and MTL tanks have small wicking holes and they need thin liquid to work properly. Stick with 50/50 VG/PG in either nic salts (10mg or 20mg) or freebase (6mg to 18mg). Anything thicker than 50/50 and the wick can't pull liquid fast enough to keep up.

Sub-ohm kits work the other way round with bigger wicking holes, more vapour per puff, and a need for thick juice to stop flooding. Go with 70/30 VG/PG and keep nicotine low at 0mg to 6mg. High nicotine in a sub-ohm tank will knock you sideways because you're taking in so much more vapour with each draw.

If your kit has adjustable wattage, check which coil is fitted. Below 0.4 ohm and you're in sub-ohm territory, so go with 70/30 and low nicotine. Between 0.4 and 1.0 ohm you're in the RDL or loose MTL range where 50/50 or 60/40 both work. Above 1.0 ohm is tight MTL and 50/50 with nic salts or higher strength freebase is what you want.

How Long Does E-Liquid Last?

Unopened, most bottles are kept for one to two years somewhere cool and dark. Heat and sunlight break down the flavour and nicotine faster than anything else.

Once you've cracked the seal, six months is a reasonable window. After that the flavour starts to go off and the taste won't be what it was. If it's changed colour noticeably or smells different from when you first opened it, bin it and grab a fresh one.

A 10ml bottle in a pod kit lasts most people two to four days. Heavy sub-ohm vapers can get through a 100ml shortfill in about two weeks depending on wattage and how often they pick the kit up.