PG vs. VG: Understanding the Difference Between Propylene Glycol and Vegetable Glycerin
Regardless of which liquid you choose, propylene glycol and vegetable glycerin are the two main things you’ll be vaping. As well as finding out what the two ingredients – called PG and VG for short – actually are, there is another crucial issue for vapers: finding the right PG/VG ratio to suit your vaping preferences. The good news is that both PG and VG are widely used chemicals that are generally considered to be safe, and finding the right ratio for your preferences is fairly straightforward once you learn the key characteristics of different PG/VG mixes. So here’s everything you need to know about PG and VG.
What is Propylene Glycol (PG)?
Propylene glycol is a colorless and slightly viscous liquid, which has almost no taste and no odor. Technically it’s an alcohol, and has the chemical name propane-1,2-diol. It’s generally recognized as safe by the FDA, and is used in a huge range of ordinary consumer products thanks to its useful properties.
It helps foods and medicines retain moisture, it’s a good solvent, it’s used to soften and smooth moisturizers and other creams, it’s used as a cheap source of carbohydrates (and a moisture-retainer) in dog food, and it’s used for its moisture-retaining and softening qualities (and as a preservative) in cosmetics. It’s used in so many things that this doesn’t even cover everything – pretty much everyone, vaper or not, consumes PG.
For vapers, PG has an important role in e-juice for a few reasons. The main reason it’s used is that it can produce a vapor easily, and it’s used in theatrical fog machines for the same reason. That’s not all, though: it’s almost odorless and tasteless nature means that it’s generally excellent at carrying flavorings, and when inhaled it produces a “throat hit” reminiscent of smoking a cigarette. In comparison to VG, it’s also less viscous, which is important when you’re thinking about how easily PG e-liquids will soak into your wicks.
What is Vegetable Glycerin (VG)?
Vegetable glycerin is a colorless, viscous liquid with no odor but a fairly sweet taste. Chemically, like PG, VG is another alcohol, and it’s technical name is propane-1,2,3-triol. Technically glycerin is a term for high-purity glycerol, and the “vegetable” part just tells you where it comes from. Like PG, VG is generally recognized as safe for ingestion by the FDA.
VG has tons of uses. It’s used in pharmaceutical creams and cosmetics because it imparts the same soothing, softening skin-feel as PG does (and it helps them retain moisture), it’s used as a solvent, it helps to keep baked foods moist, it’s used in many applications for its sweetness and it has many, many other uses. Again, you’ll come into contact with VG whether you vape or not.
For vapers, the most important qualities of VG are its ability to produce a vapor and its solvent properties. Unlike PG, it doesn’t produce a throat hit, but it creates a much thicker, denser vapor. The sweetness of VG means that it’s not as good as PG at carrying flavors, but in many mixes this extra sweetness can improve the flavor. Finally, VG is much more viscous than PG, which means it doesn’t soak into wicks as effectively.
What is a PG/VG Ratio?
Vapers have to consider the properties of a propylene glycol-vegetable glycerin mix when we’re choosing e-juice, because almost all of them contain a mixture of both ingredients. The “PG/VG ratio” of an e-juice is just what it sounds like: a measure of how much PG and how much VG are in the e-juice, relative to each other. So a 50/50 PG/VG ratio e-liquid contains 50 % PG and 50 % VG, and a 30/70 PG/VG ratio e-liquid contains 30 % PG and 70 % VG.
Although the order usually goes propylene glycol/vegetable glycerin, in some cases the ratio is quoted the other way around, a VG/PG ratio. So if this is the case, a 30/70 mix will contain 30 % VG and 70 % PG. This could easily get confusing, but thankfully most of the time when somebody writes down a ratio, they’ll specify which order it’s in, and some even write 30 VG/70 PG to make it absolutely clear.
A Guide to Choosing Your PG/VG Ratio
So now you know a little bit about PG and VG and how PG/VG ratios are expressed, the big question is which PG/VG ratio is right for you.
This isn’t too difficult to work out, but there are still quite a few things to consider, such as vapor production, throat hit, wicking ability and flavor. We’ll take a look at each of these in turn to help you make your choice.
Cloud-Chasing or Stealth Vaping?
Today, many vapers opt for higher-VG mixes for one simple reason: it produces a lot more vapor. For the “cloud chasers,” who are looking for maximum vapor production, higher-VG mixes are the only way to vape. In comparison, the vapor production from PG is thin and fairly weak. Even though it’s still enough to satisfy a new vaper, after making the switch many gravitate towards higher-VG mixes.
But there’s another side to the whole issue. Puffing out huge clouds is all well and good in the comfort of your own home, but tipping the PG/VG ratio too far towards VG can draw attention to yourself when you’re vaping out in public. Many vapers prefer something a bit more discreet for public situations, and in these cases higher-PG juices are better – you’ll still puff out some vapor, but it won’t be too attention-grabbing, especially if you hold it in a little before exhaling.
This brings us to the related topic of stealth vaping. This is like taking discreet vaping to the extreme, so you almost completely hide the fact that you’re vaping. Taking small puffs, holding the vapor in for a while before exhaling and exhaling directly downwards or through your nose makes the vapor you exhale much less noticeable, if visible at all.
Some vapers use this technique as a way to vape when they otherwise wouldn’t be allowed to, and while you may want to do this, we don’t really recommend it for etiquette purposes. It’s useful if you don’t want to draw attention to yourself even though you’re allowed to vape, but if there are laws forbidding indoor vaping in your state or the owner of the establishment you’re in doesn’t allow vaping, it’s much more polite to just vape outside.
Smooth or Harsh Throat Hit?
One of the other most important factors in choosing the right PG/VG mix for your tastes is the sort of “throat hit” you get from the juice. For just switching smoker, a harsher, smoking-like throat hit can be a really good thing because it helps to replicate the sensation of smoking. But the flip-side to this is that some smokers and particularly longer-term vapers want a bit of a smoother feeling on their throat.
For most, though, a roughly even balance (around a 50/50 PG/VG ratio) between the two offers the best of both worlds: you get a little hit on the back of your throat but not so much that it makes vaping unpleasantly harsh.
The difference in viscosity between PG and VG is also an important factor to consider. The key point is that higher-VG mixes won’t soak into your wick as well as higher-PG mixes, so you’re more likely to have problems with wicking and occasional “dry puffs” with VG-based e-juice.
This might not be a concern, though, depending on the type of atomizer you’re using. For example, early top-coil clearomizers had very poor wicking, and this meant that higher-VG mixes didn’t work well with them. Back then, most juices were high in PG for this reason. In contrast, modern sub ohm tanks tend to have excellent wicking, and most can handle even the highest-VG mixes without issues. So if you’re using a sub ohm tank (or a rebuildable atomizer), you can choose pretty much any PG/VG ratio and have a great experience, but if you’re using an earlier atomizer design (something like the Kanger Protank, for example), higher-VG mixes could still cause issues for you.
Again, roughly even VG/PG mixes give a good balance here – you get the improved vapor production and softer throat hit from the higher-VG mix, but still having a substantial amount of PG means that you’re unlikely to run into wicking issues.
Getting the Most Flavor
This point isn’t as important as the ones above, but it’s worth pointing out that e-juice with more PG usually carries flavor better than higher-VG mixes. As mentioned earlier, this is largely due to the sweetness of the VG interfering with the flavor of the juice, but this isn’t always a bad thing because it might actually improve the taste. Generally, mixers set a specific PG/VG ratio for their flavors so they can take this into account, so most of the time you don’t have to consider its impact on flavor. However, it is a general rule that it’s useful to know about.
What’s the Best PG/VG Ratio?
The million dollar question is: what’s the best PG/VG ratio for me? And sadly, the best answer we can give is “whatever you enjoy the most.” The truth is that with PG and VG, like with so many elements of vaping, personal preference plays such a big role it’s hard to give any clear advice that applies to everyone.
That said, if you want a guideline, a 50/50 PG/VG ratio is an excellent starting point, and that’s the ratio we use here at Black Note. The reasons for this are basically everything we’ve covered in this post: it offers great vapor production (without being obnoxiously cloudy), it balances smoothness against throat hit, it wicks well and it gets the most of both ingredients when it comes to flavor.
However, when you’ve tried a few juices with around a 50/50 mix of PG/VG – including some 60/40 or 40/60 mixes, which are also really common – you may be able to work out what you prefer and adjust your juice choices accordingly. In some cases – for example, if you want bigger clouds or a stronger throat hit – you might benefit from going to the extreme ends of the spectrum, like 80 % PG or VG. For most vapers, though, something close to a 50/50 PG/VG ratio is ideal.
One Last Consideration: PG Sensitivities and Allergies
Although this isn’t likely, some vapers do notice that they have a sensitivity to PG. A post on E-Cigarette Politics goes through all of the details of this, if you’re interested, but the short version is that severe sensitivity to PG is rare.
Based on forum postings, about 1 in 10 vapers experience some mild drying out or irritation of their throat. This is more the case for new vapers, because surveys have indicated that the problems clear up over time. You can think of this as developing a tolerance to the effects of PG on your throat.
There are some with a more severe sensitivity, though, estimated at around 1 in 100 users. This leads to a very sore throat when you vape, and if you experience this, you should switch to VG-based e-liquids, or at least try a higher-VG mix to see if this makes vaping more tolerable.
Even more rarely, some vapers have worse reactions to PG, more like an allergy than a sensitivity. Some, for example, experience itching or skin dryness as a result. However, since PG is used in so many consumer products, if you’re really allergic to it, you’ll probably know about it already.
Getting the right PG/VG ratio for your needs is an important part of making vaping work for you, but as we’ve learned, most vapers will be more than happy with a roughly even propylene glycol-vegetable glycerin mix. If you’re a cloud chaser looking for a smooth throat hit, you may prefer a higher-VG mix, and if you’re a just-switching smoker with a basic clearomizer looking for a good throat hit and not interested in big plumes of vapor, you may prefer a higher-PG mix, but the best advice is to try some juices out and see what works best for you.