PG VG: what an e-liquid base really contains

Two initials come back on every e-liquid label, each attached to a percentage. They name the two liquids that make up the bulk of the bottle, long before flavourings and nicotine get a look in. Plenty of people pick their PG VG split at random, or because a shop assistant suggested it, without knowing what each half contributes. Understanding the pair is how you explain why two liquids carrying the same flavour name do not taste alike.

PG VG: what the two initials stand for

PG is propylene glycol and VG is vegetable glycerine. Between them they account for roughly nine tenths of a typical bottle, with flavourings and any nicotine making up the small remainder.

Both are colourless, both are used far beyond vaping in food and pharmaceutical manufacturing, and neither carries flavour of its own in any meaningful sense. What they do carry is texture, and texture is what a PG VG ratio is really describing.

The percentages printed on a label refer only to that base. They say nothing about the flavour load or the nicotine, which is a common source of misreading.

Propylene glycol, the thin and solvent half

PG is the more fluid of the two, roughly water-like in viscosity, and it is the better solvent. Most flavour concentrates are themselves suspended in PG, which is why a PG-heavy base carries aroma more sharply.

It also produces the sensation people call throat hit, independent of any nicotine present. A 0 mg high PG liquid still has a distinct catch in the throat, which is the PG rather than anything else in the bottle.

Its thinness has a mechanical consequence too. PG-heavy liquid wicks into cotton quickly, which suits small high-resistance coils and is exactly why pod systems are built around it.

What PG does not do is produce vapour in any quantity. The visible cloud comes from elsewhere, and a very high PG liquid will look almost invisible on the exhale.

Vegetable glycerine, the thick half

VG is markedly more viscous, closer to a syrup, and noticeably sweet in its own right. That faint sweetness is not a flavouring; it is intrinsic to the molecule and it shifts the perceived taste of everything mixed into it.

It is the component that produces vapour volume. Denser clouds come from a higher VG proportion, and every high VG liquid on the market exists for that reason.

Its thickness cuts both ways. Slow wicking is fine on a large low-resistance coil with wide wicking ports, and a reliable way to burn cotton on a small high-resistance one that cannot draw it in fast enough.

VG is also the poorer solvent of the two, which is why very high VG mixes often taste slightly muted compared with the same flavour in a balanced base.

Reading a PG VG ratio on a label

The convention is not universal, which is where confusion starts. Some manufacturers write PG first, some write VG first, and the same pair of numbers can therefore describe opposite liquids.

The safe rule is to read the letters rather than the order. A bottle marked 70VG/30PG and one marked 30PG/70VG are identical, while 70/30 on its own is ambiguous until the label says which half is which.

British shelves cluster around three points: 50/50 for pod systems and mouth-to-lung tanks, 70/30 VG for sub-ohm hardware, and the occasional 80/20 or higher for cloud-focused setups. Nicotine shots follow the same clustering, in 50/50 and 70/30.

Anything outside those bands is a specialist product, and it is worth asking what it was formulated for before assuming it will behave normally.

The ratio by volume is not the ratio by mass

This distinction matters only to people mixing at home, but it catches almost all of them once.

The two liquids have different densities. VG is heavier than PG, so a 50/50 mix measured by volume is not a 50/50 mix measured on a scale, and the gap is wide enough to shift a calculation noticeably.

Commercial labels always state volume ratios, since that is what a buyer can relate to. Home mixing calculators generally work by weight, because scales are more precise than syringes, and they convert internally.

Mixing the two conventions is the origin of most home batches that come out at the wrong ratio despite the arithmetic looking correct.

What a PG VG ratio does not tell you

A ratio describes the base and stops there. Two bottles sharing a ratio can still differ in every respect that actually decides how they vape.

Flavour concentration is the first omission. A lightly flavoured and a heavily flavoured 70/30 behave nothing alike on a coil, and the ratio is silent about it.

Sweetener is the second and it is the one that costs money. Sucralose shortens coil life sharply by caramelising on the wire, and a sweetened liquid will kill a coil in days where an unsweetened one at the same ratio lasts weeks.

Nicotine form is the third. A ratio says nothing about whether the finished mix is freebase or salt, and those feel entirely different at an identical strength.

Choosing a ratio to match the hardware

The workable rule runs from the coil rather than from preference. High-resistance coils, above about one ohm, on tight-draw devices, are designed around fluid liquid and take 50/50 comfortably.

Low-resistance sub-ohm coils on airy tanks are designed around thick liquid and take 70/30 VG or higher. Putting a 50/50 into that hardware usually produces leaking rather than a flavour complaint, since the liquid floods past the wicking faster than it is vaporised.

The failure in the other direction is quieter and more expensive. A high VG liquid in a small pod coil starves the wick, and the burnt taste that follows is a dry hit rather than a bad flavour.

Manufacturers state a recommended range on the coil packaging, and it is the most reliable single source on this question.

PG VG: the points worth keeping

The pair is a trade-off with no correct answer, only a match to the hardware in front of you. PG carries flavour, wicks fast and provides throat sensation; VG produces vapour, wicks slowly and sweetens slightly.

Read the letters and not the numbers, check what the coil was built for, and remember that a nicotine shot poured into a shortfill moves the finished ratio a little towards its own.

Frequently asked questions

Does a 100 percent VG e-liquid really exist?

Rarely in a strict sense. Flavour concentrates are usually suspended in PG, so a liquid sold as full VG generally carries a small PG fraction from its flavourings.

Can two e-liquids of different ratios be mixed?

Yes, and the result is a volume-weighted average of the two. Flavour intensity averages out too, which is worth anticipating before combining a strong liquid with a mild one.

Why does a high VG liquid take so long to soak in?

Viscosity. Thick liquid moves slowly through cotton, which is why manufacturers advise leaving a freshly filled tank to stand for several minutes before the first draw.

Does the ratio affect how long a coil lasts?

Less than sweetener does. VG builds residue slightly faster, but a sweetened liquid at any ratio will shorten coil life far more sharply than the ratio itself.

Is some vegetable glycerine of higher quality than others?

The relevant marker is the grade, with pharmaceutical or food grade being the standard for e-liquid. Beyond that, sourcing differences have little practical effect in a finished mix.

What to take from a PG VG ratio

A PG VG figure on a label is a description of texture and nothing more, and it becomes useful only once you set it against the coil you intend to use it in. Thin and solvent on one side, thick and vapour-forming on the other, with the middle ground of 50/50 covering most pod hardware sold in Britain. What the ratio hides, the flavour load, the sweetener and the nicotine form, matters at least as much as what it declares. For the nicotine side of the same bottle, our nic salt shot piece explains what the small bottle contributes to the ratio, 100ml e-liquid with nicotine covers how a shortfill shifts when shots go in, and nic salt vs freebase nicotine deals with the form question the ratio leaves open.

Independent editorial content for adults only. Vaping products contain nicotine, which is a highly addictive substance. Not for sale to under-18s in the United Kingdom. This article is not a buying recommendation.