(This is currently a work in progress, and feedback and questions are highly desired).
Many people with little or no chemistry training learn to DIY e-juice, but they must learn some chemistry to do it correctly, since making juice is practicing chemistry (so are cooking food and making mixed drinks, but DIY-ing requires a bit more specialized knowledge). Sure you could just start mixing things willy-nilly, but you would likely waste a bunch of ingredients and might make yourself sick. If you want to make good juice and vape it safely, understanding the chemistry and using consistent techniques will allow you to make recipes that you like a lot, and be able to recreate your successes and avoid repeating mistakes.
Definitions
These terms should be well understood with regard to how they apply to DIY mixing:
So now we can describe a specific amount e-juice as a solution with a specific nicotine concentration and PG/VG ratio. We can also specify amounts of flavorings and any other ingredients, such as water, PGA, etc. For example, if I say I vaped 10 ml of 70PG/30VG e-juice (a solution) with a nicotine concentration of 12 mg/ml and 5% chocolate flavor, I have used a volume of e-juice (10 ml) at a specific PG/VG ratio (70/30) and flavoring concentration (6%), and I have received a dose of nicotine equal to 10 ml x 12 mg/ml = 120 mg (which is the mass of nicotine consumed). The units I used were ml, mg, and mg/ml. You can see that every concept defined in the list above is used to describe that 10 ml of e-juice. What about dilution? Yes, that is in there too, because the flavoring and nicotine base are diluted in the PG/VG solution.
Ingredients
Many people with little or no chemistry training learn to DIY e-juice, but they must learn some chemistry to do it correctly, since making juice is practicing chemistry (so are cooking food and making mixed drinks, but DIY-ing requires a bit more specialized knowledge). Sure you could just start mixing things willy-nilly, but you would likely waste a bunch of ingredients and might make yourself sick. If you want to make good juice and vape it safely, understanding the chemistry and using consistent techniques will allow you to make recipes that you like a lot, and be able to recreate your successes and avoid repeating mistakes.
Definitions
These terms should be well understood with regard to how they apply to DIY mixing:
- Volume: for our purposes, volume is a measurement of how much space is occupied by a given amount of something. The most common volume measurement you will use is the milliliter (ml). Other volume measurements include gallons, liters, cubic feet, fluid ounces, etc.
- Mass: mass is also a way of measuring an amount of something. The most common mass measurement for DIY is the milligram (mg). Other mass measurements include grams, kilograms, ounces and pounds. Note that ounces and pounds can also describe weight, which is not quite the same as mass, but an explanation of that is not needed for this discussion.
- Concentration: this describes the strength, or relative amount, of a given substance in a mixture. The most common concentration measurements you will use for DIY are % and mg/ml. Note that many people and vendors just say "mg" when describing nicotine concentration, but that is not correct and can lead to some confusion.
- Units: This is the way to express which measurement system you are using. Units commonly used for DIY include ml, mg, and %. No measurement description is complete unless the units are provided. If you ask me how much water to add to a mix and I say, "Four," that is not very helpful. If I say 4 ml, you know what I am talking about without guessing. Strive to always include proper units with any measurement you describe.
- Solution: A solution is a liquid with more than one substance (a mixture). Unless you vape straight VG or PG, your juice will be a solution.
- Ratio: A ratio describes how much of one thing there is compared to another thing. Ratios can be shown in different ways, for example 3 to 4 and 3:4. Percentages and fractions are actually ratios too, but they may be one sided; for example I can say that a mixture is 50% VG, or equivalently 1/2 VG, without specifying what the rest of the mixture is.
- Dose: A specific, finite amount of something. For nicotine, if you vape 3 ml of juice that has 12 mg/ml nicotine, you have vaped 3 x 12=36 mg of nicotine, which is the dose you have consumed. How much your body has actually absorbed is another question entirely, and not needed for this discussion.
- Dilution: Reducing the concentration of one or more substances in a solution. If you add PG, VG, water, and/or water to a nicotine base solution, you have diluted the nicotine concentration of the base solution.
So now we can describe a specific amount e-juice as a solution with a specific nicotine concentration and PG/VG ratio. We can also specify amounts of flavorings and any other ingredients, such as water, PGA, etc. For example, if I say I vaped 10 ml of 70PG/30VG e-juice (a solution) with a nicotine concentration of 12 mg/ml and 5% chocolate flavor, I have used a volume of e-juice (10 ml) at a specific PG/VG ratio (70/30) and flavoring concentration (6%), and I have received a dose of nicotine equal to 10 ml x 12 mg/ml = 120 mg (which is the mass of nicotine consumed). The units I used were ml, mg, and mg/ml. You can see that every concept defined in the list above is used to describe that 10 ml of e-juice. What about dilution? Yes, that is in there too, because the flavoring and nicotine base are diluted in the PG/VG solution.
Ingredients
- The most common ingredients in e-juice are propylene glycol (PG), vegetable glycerine (VG), nicotine, and one or more flavorings. You could vape straight PG or VG, so everything else can be considered optional. Other commonly used ingredients include distilled water (DW), pure grain alcohol (PGA).
- About nicotine base solutions: various nicotine concentrations are available, but 100 mg/ml should be considered a maximum for safe DIY-ing. You may be more comfortable starting with a lower concentration and that is fine, but anything higher than 100 mg/ml should be avoided. 100% nicotine is extremely dangerous and should only be handled by trained chemists in fully equipped laboratories. Note that 100 mg/ml is equivalent to 10% nicotine. Some people mistakenly describe 100 mg/ml as 100% nicotine, and that should set off alarm bells every time it happens.
- Flavorings for vaping are normally flavor concentrates in a solution of PG, VG, and/or PGA. It is a mistake to assume that natural flavorings are always safer than artificial ones. Most of us prefer natural flavorings when we can use them, but not all natural flavorings are good for vaping. For example, any sugar (honey, molasses, agave syrup, etc.) is a natural flavoring, but if you put it into your juice, it will gunk up your coils quickly and is not a good thing to have in your lungs. Sometimes the line between "natural" and "artificial" flavorings is not distinct; stevia is a "natural" substance, but it is also an artificial sweetener, since it does not contain sugar. If you are seriously afraid of artificial flavors, I recommend trying unflavored e-juice. My main vape is 90% VG, 10% water, 33 mg/ml nicotine, nothing else.
- There are additives which are used like flavorings, but are not flavors in and of themselves. Common additives include sweeteners, acetyl pyrazine (AP), and ethyl maltol (EM), but many other things have been used.
