The Short Answer
E-liquids are made up of three or four main ingredients. They are Propylene Glycol (PG), Vegetable Glycerin (VG), artificial and/or natural flavourings, and nicotine (if you choose to mix it in).
Generally, they have proven safe to vape so far. Long-term studies of inhalation of these liquids are still yet to be carried out, and you need to buy them from reputable suppliers in countries where there exist standards for food-grade ingredients, but right now it’s accepted that you’re not going to do much harm with some inhalation of these ingredients, and either way it’s far less harmful than smoking.
The Long Answer
This is where things get interesting, and far more scientific.
The term “natural and/or artificial flavourings” can be a bit misleading. Generally, the flavours come from extracts made from the actual ingredient, although at times they can be made in a lab with things such as ester odorants; chemical compounds which have the smell or taste of a particular food.
But let’s get to flavours after we cross off the other liquid ingredients.
Propylene Glycol is an organic liquid compound, colourless and odourless with a faintly sweet taste. It’s produced from propylene oxide for food-grade purposes, purified at between 150 and 220 degrees with trace amounts of sulfuric acid or alkali, and then further purified to result in the 99.5%+ USP-grade propylene glycol used in e-liquids.
PG is used as a humectant, solvent, and as a preservative for food and tobacco products. It’s in coffee-based drinks, liquid sweeteners, ice cream, whipped dairy products and soft drinks. It’s in many pharmaceuticals that are insoluble in water. It’s also in cake mixes and icings, food colourings and even salad dressings. Chances are, you’ve consumed some propylene glycol during the course of your day.
In e-liquids, PG is the flavour carrier. It’s the slightly thinner liquid (still far thicker than water) in which flavour extracts are delivered; even “Max VG” e-liquids contain up to 10-15% PG. It also creates the “throat hit”, or the roughness on the back of the throat upon inhale that many vapers enjoy, and which makes vaping somewhat similar to smoking. An absence of PG makes for a very smooth liquid with muted taste.
A very small percentage of the population has a sensitivity to propylene glycol. It’s generally accepted that the percentage of people with even a slight sensitivity to PG is between 1.5 and 3.5%, and this is usually only this high among people who suffer from allergic contact dermatitis. PG sensitivity manifests itself mostly in inflamed dry skin or small red dots on the body, but through inhalation can also introduce a dry or sore throat, or a worsening of existing tinnitus (ringing in the ears). These side effects are reported in as few as 1 in 5,000 people, however, so chances are that if you’re experiencing symptoms from vaping, it’s not PG but rather the body readjusting to your quitting smoking.
Oh, and it’s not the “key ingredient in anti-freeze”, despite what the mainstream media would have you believe. That’s ethylene glycol, a highly-toxic substance which is almost completely different.
Vegetable Glycerin, often called Glycerin (with or without an ‘E’ at the end) or Glycerol, is another colourless and odourless liquid with a sweet taste. It’s thick (much thicker than PG) and non-toxic. It’s produced from triglycerides found in plant and animal sources; soybeans and palms are common plant-based sources, and tallow is a common animal-based source. These are treated with ethanol and a catalytic base such as activated carbon or alkali to produce glycerol at the 99.5%+ purity used in e-liquids.
VG is also used as a humectant, solvent, preservative and sweetener for food products. It’s a thickening agent in some liqueurs, as well as a filler in cookies. It’s used in cake icing to stop it from hardening, but so that it can remain thick. It’s found in cough syrups, toothpaste, mouthwash, skin care and shaving products, hair products, soaps, and is the main ingredient in personal lubricants. It’s even used as a replacement or additive to water during film shoots to slow down the drying out process.
In e-liquids, VG is used as the cloud producer. It’s the thicker liquid that is often used in higher-wattage devices as it’s more difficult to wick up onto the cotton coils in low-powered vapes. It reduces throat hit, smoothing out a vape when it’s too harsh. It can also mute a flavour when used in high concentrations, but it’s the main reason you see people blowing large amounts of vapour. If you’re going for “mad clouds”, go high VG.
The deal with nicotine
If you choose to use nicotine in your liquids in Australia, you’ll need to import it for personal use. Nicotine itself is listed as a Schedule 7 Dangerous Poison, and as such is not available for sale within the country. Why is it available in cigarettes, you ask? There’s exemptions in Australian law allowing the sale of nicotine “in preparations for human therapeutic use or in tobacco prepared and packed for smoking”. Since electronic cigarettes are not an accepted smoking cessation device, there’s currently no exemption that exists for the sale of nicotine for this purpose. Laws regarding the use and possession of nicotine vary by state, so check your individual state laws before proceeding.
Nicotine for use in e-liquid is extracted from the tobacco plant, which is native to the American continents. It’s most often extracted from the rustica tobacco plant (nicotiana rustica) as this particular form of the tobacco plant is highly potent, and not traditionally used for smoking tobacco. Methods of extraction vary depending upon suppliers.
The resulting substance is usually provided in a PG or VG base (or a mix of both) at anywhere up to 1000 mg/ml (“pure nicotine”). Large quantities of liquid nicotine can be preserved in a freezer for longer periods of time; left out to the elements, nicotine will change to a pinky colour as its lifespan decreases.
Nicotine in high mg/ml strengths is very harmful, so it’s best to stick to an absolute maximum of 100 mg/ml when mixing, and use protective gear including gloves and eye protection when handling. Skin contact should be avoided, and ingestion is a no-no. Handled properly, nicotine can be mixed easily and accurately with a syringe, but if in doubt please always contact an expert or your local vape shop.
Now, about those flavourings
This is where things get really interesting. Most e-liquids that you encounter will state that their ingredients are “natural and/or artificial flavourings”, but this isn’t accurately representing the entire story. There’s a lot more to how these flavours come about, and a lot more than just one ingredient.
Major suppliers of extracts for e-liquid include FlavorArt, Capella and The Flavor Apprentice (TFA), among others. Here’s the ingredients, from a material safety data sheet (MSDS), for TFA’s Banana Cream flavour concentrate:
- Propylene glycol (80-90%)
- Isoamyl acetate (1-5%)
- Butanoic acid (1-5%)
- Ethyl vanillin (1-5%)
- Isoamyl isovalerate (1-10%)
- Acetoin (1-5%)
- 2-Heptanone (less than 0.5%)
- Eugenol (less than 0.5%)
- Butyrate <3-methylbutyl, 2-methyl> (less than 0.5%)
Now, are we confused enough? Where’s the banana?
Well, here’s what each of those ingredients do. The Butanoic acid gives an acidic, creamy nuance to the liquid; Ethyl vanillin adds more cream, as well as sweetness and smoothness; Isoamyl isovalerate is a green, fruity apple scent and 2-Heptanone is a green, fruity scent, too, as is Butyrate; and Acetoin adds a sweet, creamy, buttery accent. The Isoamyl acetate is where the banana comes from – it’s described as “sweet, fruity, banana-like with a green ripe nuance”.
All of this is held in the 80-90% PG base. When diluted into e-liquid form, these are further distilled; you’ll generally get about 10% concentrate in your pre-mixed bottle of e-liquid, which means the Isoamyl acetate comes to somewhere between 0.1-0.5% of the finished product.
It’s probably starting to sound a little scary at this point, but don’t be too worried. Even many foods that we wouldn’t think twice about eating contain these ingredients, and chances are that they will do us no harm. Isoamyl acetate is in most banana-flavoured cake mixes, drinks and lollies.
Even the “natural” versions of these flavours contain many of these ingredients. As an example, one of the ingredients in TFA’s Cinnamon concentrate is Cinnamic aldehyde; this is evident in most (if not all) artificial versions of cinnamon flavourings as well as natural versions.
That brings us to…
We’re now back to the basic list of ingredients. Your e-liquids contain Propylene Glycol (PG), Vegetable Glycerin (VG) and natural and/or artificial flavourings. Hopefully now, though, you’ve got a better understanding of the process through which these ingredients are attained in order to be mixed into your liquids.
Finding that perfect Banana Cream flavour isn’t simple; professionals have spent countless hours perfecting that one recipe, making it as accurate and safe as possible. When it’s made into a pre-mixed liquid, it could be combined with some others to create a new, interesting flavour. Maybe it’s even your favourite All Day Vape.