PG/VG Ratio Problems: What the Numbers Mean

Technical guide · Puff Club Vape Leduc

Part of Liquids, nicotine and taste

E-liquid (the liquid used in a vape device) is made from two main base liquids: propylene glycol (PG) and vegetable glycerin (VG). The ratio on a bottle tells you how much of each is in the mix. A 50/50 liquid is half PG and half VG. A 70/30 liquid is usually listed as 70 PG to 30 VG, but always read the label wording, because some brands print the VG number first.

PG is a thin, runny liquid. It carries flavour and nicotine well and gives a sharper feel in the throat. VG is a thick, dense liquid. It makes more visible vapour and gives a smoother feel. When a device and a liquid ratio do not match, common problems appear. This guide explains what the ratio means and how to fix the issues it causes.

Why it happens

Most ratio problems come from a mismatch between the thickness of the liquid and the way the device is built. The coil (the heating element that turns liquid into vapour) has small openings for liquid to enter. A thin liquid moves through those openings quickly; a thick liquid moves through slowly.

A liquid with a high PG share, such as 70 PG / 30 VG, is thin. In a device built for thicker liquid, it can overfeed the coil, which causes leaking, gurgling, or liquid spitting into the mouth. High PG also gives a stronger throat hit, so it can feel harsh or scratchy, especially at higher nicotine levels or higher power.

A liquid with a high VG share, such as 30 PG / 70 VG, is thick. In a device built for thinner liquid, the coil cannot absorb it fast enough. The result is a dry hit, which is a burnt, harsh puff that happens when the coil heats with too little liquid on it. Thick liquid can also shorten coil life and produce weaker flavour in small devices, because PG carries flavour better than VG.

In short, the problem is rarely the liquid itself. It is almost always the wrong ratio for the specific device, coil, or puffing style.

Step-by-step fix

1. Read the ratio on the bottle. The label shows two numbers, usually with PG first. Confirm which number is PG and which is VG before making any change.
2. Match the symptom to the cause. Leaking, gurgling, or spitting usually means the liquid is too thin for the device. Dry hits, a burnt taste, or weak flavour usually means the liquid is too thick for the device.
3. Match the ratio to the device type. Small pod devices and mouth-to-lung tanks (where vapour is first drawn into the mouth, then inhaled) use high-resistance coils and work best with thinner liquid, around 50/50 or higher PG. Large sub-ohm tanks (coils with resistance under 1.0 ohm, a unit of electrical resistance) use a direct-to-lung draw, where vapour goes straight into the lungs, and work best with thicker liquid, around 70/30 with VG as the larger number or higher.
4. Fix harshness. If the vapour feels sharp or scratchy, lower the power setting, use a lower nicotine strength, or switch to a liquid with more VG. Change only one thing at a time so you can tell what helped.
5. Fix dry hits. If you get burnt-tasting puffs, allow more time between puffs so the coil can reabsorb liquid, lower the power setting, or switch to a thinner liquid with more PG. If you keep a high-VG liquid, make sure your coil is rated for it.
6. Fix leaking. If the device leaks or gurgles, switch to a thicker liquid with more VG, check that the coil is seated correctly, and confirm the tank is closed tightly.
7. Retest after each change. Make one adjustment, vape normally for a short period, and note whether the problem improved before making the next change.

Prevention

Choose the right ratio from the start. Note your device's coil resistance and recommended liquid thickness before buying liquid. Small, low-power devices are built for thinner, higher-PG liquid; large, high-power devices are built for thicker, higher-VG liquid.

Keep a written note of the ratio that works for each device you own. When you buy a new liquid, check the ratio on the label instead of going by habit, because the same product line can change ratios.

Store liquid correctly. Keep bottles closed, upright, and away from heat and direct sunlight, because heat thins the liquid and changes how quickly the coil absorbs it.

Replace coils on schedule. A worn coil struggles to keep up with any liquid, which makes ratio problems worse and harder to diagnose.

If a new liquid causes a problem you cannot trace, return to a ratio you already know works, then test changes from that stable starting point.

This guide is general technical information and is not medical or legal advice.