VG vs PG in E-Liquid - The Definitive Guide
Many people who visit our stores purchase 10ml e-liquid bottles which we mostly refer to as 50/50's. It is common for our customers who perhaps have never tried sub-ohm kits to ask what exactly is the difference between the 10ml bottles and the 50ml (or greater) bottles mostly known as shortfill e-liquids.
Except for the nicotine being added to the 50ml bottles after purchase, what separates them? Before the idea of vaping came to be, the components which make up e-liquids had to be refined and characterised by how they enhance flavour, vapour production, throat hit and even how the vapour feels as you pull on an electronic cigarette.
Vegetable Glycerine (Known colloquially as VG) is a clear, flavourless, odourless and water soluble polyol (Meaning organic compound). Produced from plant oils, typically palm oil, soy, or coconut.
Propylene Glycol (Or PG) is also an organic compound which is colourless and nearly odourless with a slightly sweet taste. The main differences between the two with regards to vaping stem from their combined viscosity, which is the thickness of the liquid.
Looking back to the first part of this article, we refer to the 10ml bottles as 50/50's because that is the ratio of PG/VG which has been used. That is to say that for one part of VG in the mixture, the same amount of PG is added. Other differences when vaping come down to a balance of vapour production and throat hit. A higher ratio of VG to PG, for example 70/30, would produce far greater volumes of vapour than a 50/50 liquid in the same tank.
This is because VG is 20% more dense than PG, meaning that a tank using 100% VG liquid will produce 20% more vapour than a 100% PG liquid. This is a theoretical scenario I made up to prove a point, please do not vape 100% PG liquids... On the other hand, a liquid with a balanced VG/PG ratio (Such as our 50/50's from earlier) aim to provide a greater throat hit without needing more nicotine. Since PG is also much less dense than VG it also thins the liquid, allowing tanks to use much more compact and complex geometry for their coils.
It is for this reason that you do not often see pod kits which suggest using high VG liquids, except when using particular coils or a separate style of pod entirely (Such as the Smok Fetch Pro). The applications of these characteristics are the backbone of e-liquid research and development.
For smaller kits, such as starter kits and pod kits, 50/50 liquids are recommended as these vape kits are generally not able to achieve the necessary power output to produce the throat hit desired by the customer. Many of the smaller kits such as the PockeX explicitly state that they are for use with 50/50 liquids only, as the coils have been developed specifically for use with liquids at a particular viscosity.
Important note: High VG Liquids are considered any liquids which contain a ratio greater than 1:1 VG:PG. Round numbers are generally used, a 60/40 liquid may not be considered high VG as this ratio can still work well in small systems and pods.
Larger sub ohm kits, and some pod kits which come with tanks such as the Voopoo Drag 3, or the Smok Scar-18, have been designed to accommodate much thicker liquids by widening the juice inlets, using a lot more cotton and implementing new ideas into their kits. The most recent of which that has really taken a hold of the sub-ohm market being mesh coils.
Many tanks which accept high VG liquids will also happily accept 50/50 liquids, but be prepared for a much stronger throat hit as well as potentially reduced coil life and leaks since the 50/50 liquids are much thinner than high VG liquids and therefore can run off the coil and into the air inlet, especially after a vaping session when the system is warm.
Imagine trying to keep a stick of butter on the end of a red-hot poker, that's what your coils are trying to do when you use a liquid too thin for the tank. Conversely, imagine trying to empty a syringe full of peanut butter by sucking on the end of it... not gonna happen.
This is similar to what happens when you use high VG liquids in tanks built for 50/50. The wick will eventually dry over a session of vaping and you will get dry hits, the bane of any vaper.
Whatever your needs are from vaping, the considerable flexibility from different ratio blends can accommodate any individual. We at Royal Flush Vape are happy to help you pick out the right stuff for your kit, no matter your needs.