Getting Started with Shortfill E-Liquids

As soon as you’ve learned the basics of vaping with 10ml bottles and you have found a flavour you enjoy, you may be thinking about moving on to shortfill bottles. Shortfill is usually a cheaper way to vape, and allows you greater control over your nicotine intake.
But what actually are short fill e-liquids? How do they work, and how do you mix them correctly?I’ll explain everything you need to know in this beginner’s guide:

What are Shortfill E-Liquids?
Shortfills are bottles of nicotine-free e-liquid with enough room in the bottle to add a separate shot of nicotine. Shortfill bottles are typically filled to five-sixths capacity. So for example, if you buy 50ml of shortfill it usually comes in a 60ml bottle (leaving just enough room to add a single 10ml nicotine shot). 100ml shortfills usually come in a 120ml bottle, which is big enough to take 2 nicotine shots, and so on. 
Shortfill bottles were created in response to the Tobacco Products Directive (TPD), an EU-wide law that made it illegal to sell any “nicotine-containing liquid” in bottles bigger than 10ml footnote 1. Shortfill contains no nicotine whatsoever, so it’s perfectly legal for a UK vaper to buy a 25ml, 50ml, 100ml or 200ml bottle, then add their own shot of nicotine at home. 
Nicotine boosters are usually sold in 10ml bottles at a strength of 18 or 20mg/ml (the legal maximums under the TPD are 10ml and 20mg/ml). An 18mg/ml shot will give a 50ml bottle a nicotine strength of exactly 3mg/ml (180 mg of nicotine divided by 60 ml of vape juice), whilst a 20mg/ml shot will make it 3.3mg/ml. Other nicotine strengths, and the nicotine:shortfill ratios you’ll need to achieve them, are explained further down in this article.
Shortfill bottles are great because they allow committed vapers to buy more than 10ml of e liquid at a time. A 50ml or 100ml shortfill bottle is more convenient for the vaper, better for the environment (less packaging) and slightly cheaper, too. 

When to use shortfills
It takes time to get used to vaping and find your favourite flavours, so we don’t actually recommend starting out with big bottles of shortfill. If you’re a new tobacco quitter and you’re starting to vape for the first time, it’s best to start with a few smaller bottles of e-liquid of different flavours and VG/PG ratios.  That way, you’ll waste less money if you don’t like a flavour, and you can get a feel for how the VG/PG balance changes the flavour and density of your vape. 
Once you’ve got past those first few weeks of vaping, you’ll know what you’re doing and you’ll have a bit more confidence about the brands you like and the flavour profiles you enjoy. At this stage, shortfills are the perfect option. You can buy a bigger amount of your favourite vape juice, punch it up with a nicotine booster if you need to, and get on with your day.

How do you mix shortfill e-liquid?
If you’re looking for a simple 3mg/ml or 6mg/ml strength, it’s a very simple four step process…
1.You open your shortfill bottle, 
2.You pour in your nicotine shot(s),
3.You close and shake the shortfill bottle
4.You give the liquid a moment to settle, then you’re good to go. 

Safety Notes: The nozzle lids are often very tight, and it can be tricky to get these off. We sell a shortfill bottle opener if you need one.  You should always mix your shortfill on a level surface like a desk or kitchen table (these bottles are tiny and you don’t want to spill any), and wash your hands afterwards just to get any trace of nicotine off your fingertips.

How much nicotine do I add to shortfill?
Should you go for a 3mg/ml or 6mg/ml strength? What about other strengths like 1.5mg/ml and 9mg/ml? The nicotine:shortfill balancing act can be confusing if you’re new to vaping, but it doesn’t take long to learn the basics. 
We have a table with some basic nicotine strength calculations further down in this article, but if you’re completely new to vaping, you first need to understand how nicotine is measured in shortfill e-liquid. Bear with me here…

Nicotine in a cigarette: it’s always mg
Before the rise of vaping in the late 2000s, the nicotine content of pretty much anything could be measured in straightforward milligrams (mg). If you were smoking a single cigarette, using one patch or chewing a piece of nicotine gum, you could find out exactly how many milligrams of nicotine your body was getting from that one ‘dose’, often just by reading the packet. It’s slightly more complicated with vaping, however. 

Nicotine in an e-liquid: it’s’ always mg/ml
You can’t use a simple ‘mg per dose’ measurement with shortfill e-liquids, because everyone’s idea of a ‘dose’ is different. Some vapers might take five or six long draws on their device and call that a dose, whereas others might take fifteen or twenty short puffs every hour throughout the day. Vaping devices also burn through e-liquid at different rates, which affects how much nicotine-infused vapour you inhale. The same goes for the VG/PG ratio of your liquid. This makes it impossible to give a reliable, universal ‘milligrams of nicotine per vape’ number. What we can do, however, is measure how much nicotine is in the e liquid before it’s vapourised. That’s why the nicotine content of an e liquid is always measured in milligrams per millilitre (mg/ml). 
So how much nicotine is right for you? Ultimately, you have to make your own decision on this, but we can tell you is how much nicotine you’ll find in a cigarette or patch, and what most of our shortfill customers buy in a given month. 

How much nicotine is in cigarettes and patches?
Let’s take a look at cigarettes and nicotine replacement products…
One cigarette carries anywhere from 0.5mg to 1.6mg of nicotine 24 hour nicotine patches deliver anything from 7mg to 21mg over a 24 hour period footnote 3
Nicotine nasal sprays and ‘quick mists’ deliver anything from 0.5mg to 1mg of nicotine per dose (max. 64 doses a day) 
Safety Note: We’ve taken the stats above from reliable UK sources (you’ll find citations at the bottom of this article), but please bear in mind that cigarettes, patches and e-cigarettes all deliver nicotine in different ways. The rates of absorption into the body are different in each case.

What’s the most popular shortfill nicotine strength?
Most of our customers will buy 3mg or 6mg strength shortfills. Gareth and I took a look at last month’s sales report, and the majority of our 50ml shortfill customers (68%) bought a nicotine shot for 3mg/ml strength. 12% bought enough nicotine for a 6mg/ml strength, and the remaining 20% didn’t get any nicotine at all. The same rough stats play out on sales of our 100ml bottles (69% bought 3mg/ml strength) and 200ml bottles (71% bought 3mg/ml strength).

How to measure nicotine content correctly
When you buy a shortfill on our site, you’ll normally see an “Add Nicotine Shot For...” option on the right-hand side. You can choose from 0mg, 3mg or 6mg, and we then send you enough nicotine shots to boost your shortfill to the strength you’ve chosen.

We prefer to send you the right amount of nicotine up-front so that all you have to do is add one bottle to another and shake (it’s a much simpler way of doing things), but if you really want to customise your shortfill nicotine dose yourself, you can still do this. To calculate a more precise nicotine strength than 3 or 6, you just have to follow three simple steps:

Step 1: Figure out how much nicotine you’re going to add
Multiply the mg/ml value of your nicotine shot(s) by the number of millilitres in the nicotine shot bottle. So for instance, if you have 2x 10ml bottles of 18mg/ml strength, that would give you a total of 360mg of nicotine (20ml x 18mg/ml = 360mg).
Step 2: Figure out how much vape juice you’re creating
Add the amount of fluid in your nicotine shot(s) to the amount of fluid in your shortfill bottle. For instance, if you add 2x 10ml nicotine shots to a 100ml shortfill bottle, you’ll end up with 120 ml of vape juice (100ml shortfill + 10ml shot + 10ml shot)
Step 3: Divide the total nicotine by the total vape juice
Take the total mg of nicotine (step 1), and divide it by the total ml of vape juice (step 2), and you’ll get your nicotine strength in mg/ml. Using our example above, if we add 2 of the 18mg/ml strength shots to our 100ml shortfill bottle, we’ll end up with 360 mg of nicotine. 360mg of nicotine divided by 120 ml of vape juice gives us a strength of 3 mg/ml

To increase the strength beyond 3mg, you’ll probably need to decant some of your shortfill fluid before you add the nicotine shot. For a strength of less than 3mg, you’ll probably want to use a fraction of one full nicotine shot. 

Do Nicotine Shots Dilute Flavour?
Nicotine shots are flavourless, but they will still dilute your vape juice when you mix them into your shortfill, just like cordial in a glass of water. It’s not just the flavour that can be affected - the VG/PG ratio can change when you add a nicotine shot, too. If you’re making a custom nicotine strength, you’ll need to find a nicotine shot that matches the VG/PG of your shortfill liquid - otherwise you won’t get the balance of vapour density and flavour you’re expecting. 
You shouldn’t need to worry about shortfill dilution too much. We always try and send out nicotine shots that complement the VG/PG ratio of the e-liquid we’re selling (normally 80% or 100% VG), and most of the manufacturers we work with will make their shortfill flavours a little stronger to allow for the addition of a nicotine shot. 
I don’t feel like I’m getting enough nicotine. What do I do?
If you don't feel like you’re getting enough nicotine from 3mg or 6mg strength shortfills, you might need to stick with a stronger pre-mixed 10ml bottle for a while, just until you can safely wean yourself off those higher nicotine doses.

It can be unnerving to keep dosing yourself with nicotine when you’re trying to quit, but in my experience it’s worth it if you’re trying to kick the cigarettes completely. The NHS say that it can actually be a good thing to supplement your vape with nicotine patches - the patch gives you a ‘background level’ of nicotine from another source while you get to grips with your shortfill vape and break the behavioural habit of lighting up a cigarette.

In summary…
In an ideal world, we wouldn’t need to add our own nicotine to shortfill e-liquid bottles — it would be easier if we could buy a finished product pre-mixed in a size that suits us — but while the Tobacco Products Directive remains law, this is how we do it. 
The TPD law isn’t scheduled for review until 2022 footnote 6, so for now, shortfills are here to stay. With a bit of practice, you can use shortfills to save money, cut waste and get more pleasure out of your vaping experience. 
I hope this guide has given you a good starting point on how to use shortfills, make vaping a little more convenient for you and help you save money. If you do have any questions, we’re always here - just send us an email. The team and I will be happy to help. 
Stay safe and happy vaping!