What Is a Longfill and How Does It Work
What is a longfill
and how does it
actually work?
A plain-English UK guide to the longfill format. The 60ml bottle, the 30ml of concentrate, the shots you add yourself plus why this setup saves you money compared with buying six separate 10ml bottles.
A longfill is a 60ml bottle sold with 30ml of nicotine-free flavour concentrate inside. The remaining 30ml is left empty on purpose so you can add your own nicotine shots plus VG/PG base at home. When you shake it all together you end up with a full 60ml of ready-to-vape e-liquid at a known strength. The format exists because UK law caps pre-filled nicotine bottles at 10ml. Buying one 60ml longfill is significantly cheaper than buying six 10ml bottles that add up to the same volume.
Three numbers
that define every longfill
Once you know these three numbers the whole system makes sense. Size, fill level plus the gap for your shots.
Bottle size
Industry-standard longfill volume. Large enough to save money, small enough to use before flavour degrades.
Concentrate inside
Half full from the factory. Highly flavoured nicotine-free base waiting for your chosen shots.
Typical saving
A longfill plus Mixer Kit costs around 40 percent less per ml than six pre-filled 10ml bottles.
A longfill is the UK vaping industry’s workaround to a 10ml rule.
In May 2017 the Tobacco and Related Products Regulations 2016 came into force across the UK. One of the headline rules was that any e-liquid containing nicotine could only be sold in a bottle of 10ml or smaller. For vapers who were used to buying 30ml or larger bottles this was a problem. A heavy sub-ohm user could get through 10ml in a single day which meant a weekly trip to the shop plus a much higher price per millilitre.
The industry responded with two solutions. The first was the shortfill: a larger bottle filled with flavoured nicotine-free liquid leaving a small gap at the top for a single 10ml nic shot. The second was the longfill: an even bigger gap with a concentrated flavour base waiting for multiple nic shots plus VG/PG base. Longfills cost less per ml because they ship with less liquid inside the bottle. They also give the user more flexibility on the final nicotine strength plus VG/PG ratio.
A typical longfill in the UK is a 60ml bottle that arrives with 30ml of flavour concentrate already inside. The remaining 30ml is left deliberately empty. That empty space is designed to be filled with three 10ml bottles of base liquid containing your nicotine shots. Once you add them, shake the sealed bottle for one full minute plus wait a short rest, you have a complete 60ml of ready-to-vape e-liquid.
Why is the concentrate so concentrated?
Because the finished liquid will end up at roughly half the original flavour strength once the base liquid is added. If the flavour was mixed at normal strength on day one, by the time you added 30ml of mostly unflavoured base it would taste watered down. Longfill concentrates are therefore formulated at roughly double strength so the finished mix tastes balanced rather than thin.
- Nicotine. Added via shots in the base. Usually 18mg freebase or 10mg nicotine salt depending on the kit.
- VG and PG. The carrier ratio is chosen when you pick a Mixer Kit. 50/50 for pod and MTL, 70/30 for sub-ohm.
- Flavouring. Already in the bottle at double strength, ready to be diluted by the base.
What is actually
inside the bottle
A visual breakdown of a standard UK 60ml longfill bottle. The amber layer is what you add yourself. The teal layer is what arrives in the box.
Child-proof cap plus dripper nib
TPD requires both. The nib pops out to pour in your shots then goes straight back before resealing.
30ml of empty space
The gap where you add your three 10ml bottles of base plus nicotine. Deliberately left unfilled from the factory.
30ml of flavour concentrate
Nicotine-free, PG-based plus roughly double strength. Designed to dilute down to normal intensity once mixed.
Labelled bottle with batch info
Flavour name, manufacturer details, best-before date plus TPD-compliant warnings printed on every bottle.
How a longfill goes from
half-full to ready-to-vape
Four actions separate a freshly purchased longfill from your vape tank. None of them take longer than a minute.
Choose a flavour
Browse the longfill range plus pick a concentrate. Each flavour lists its recommended Mixer Kit.
Choose your kit
Match with a Mixer Kit at your chosen strength plus VG/PG ratio. Three 10ml bottles ship inside.
Pour plus shake
Empty all three Mixer Kit bottles into the longfill. Shake sealed for one full minute until uniform.
Fill your tank
Fruit plus menthol are ready in fifteen minutes. Rest desserts for 24 to 48 hours in a cool cupboard.
Browse the full
Nixer longfill range
Every Nixer longfill ships pre-loaded with 30ml of UK-made flavour concentrate. Every bottle pairs with a matched Mixer Kit. Pick a flavour, pick a strength plus let the system handle the ratios.
Now you understand what a longfill actually is, picking one is the easy part. The full Nixer longfill collection groups every flavour by style so you can skip straight to fruit, dessert, menthol or tobacco depending on what you are in the mood for.
Longfill vs shortfill
vs pre-filled 10ml
Three ways UK vapers buy e-liquid. Which one fits depends on how much you vape, what strength you want plus how much flexibility you care about.
10ml pre-filled
- Grab-and-go simple. Open the cap plus vape straight away with no mixing.
- Full strength options. Available up to 20mg nicotine plus in nic salts.
- Highest price per ml. Around 40p per ml is the market standard.
- Fixed ratio. VG/PG pre-decided by the maker with no flexibility.
- Best for light users. Makes sense if you vape one tank or less per day.
Shortfill
- Mostly ready. Add one 10ml nic shot, shake plus vape.
- Usually 3mg finished. Aimed at sub-ohm vapers who want low strength.
- Mid-range price. Typically 20p to 25p per ml of finished liquid.
- Limited strength ceiling. Going above 3mg means emptying some out first.
- Best for sub-ohm vapers. Built around 70/30 VG/PG ratios for cloud production.
Longfill
- Full flexibility. Choose freebase or nic salt, 50/50 or 70/30 plus any strength up to the cap.
- Every strength supported. From 0mg through 9mg freebase or 10mg nic salt.
- Lowest price per ml. Typically 16p to 18p per ml of finished liquid.
- Works with any device. Pod, MTL or sub-ohm depending on your kit choice.
- Best for regular vapers. Pays back after two or three bottles compared with 10ml alternatives.
Four reasons longfills
keep gaining UK market share
Lower cost per ml
Roughly 40 percent cheaper per ml than pre-filled 10ml bottles. A heavy user can save £30 to £50 a month.
Flexible strengths
Nic salts for pod kits, freebase for sub-ohm, 0mg through 10mg finished options. One format covers every device.
Less packaging waste
One 60ml bottle plus three small mixer bottles replaces six separate 10ml bottles. Roughly half the plastic.
Longer shelf life
The concentrate stays stable unmixed for longer than pre-made e-liquid. Buy bottles ahead without waste.
For the wider picture on longfills including mixing instructions, strength guides plus flavour recommendations, head to our full Nixer vape review hub where we cover every practical question UK longfill users ask as they make the switch from 10ml bottles.
Back to the Nixer Vape Review hub
This article is one chapter in our complete Nixer knowledge base. Head back to the hub index for the full range of guides on mixing, strengths, steeping plus the Mixer Kit.
More on longfills
& how they work
Now you understand the longfill format in general, the next step is often the mixing itself. Our practical walk-through on how to mix a longfill bottle step by step covers the method for any brand. For the Nixer-specific version of this guide which explains exactly how the Dispergo system differs from generic longfills, see what is Nixer longfill vape juice and how does it work. Plus if you are weighing up whether the numbers actually add up, how much e-liquid you get from a Nixer longfill once mixed breaks down the finished volume.