What are longfills?

What makes longfills different

Where a shortfill comes mostly pre-mixed and you just add nicotine, a longfill comes with just the concentrated flavour and a portion of PG. You add the rest: more PG or VG, plus the nicotine. The bottle is mostly empty when you buy it.

Longfills give you the flexibility to choose your own VG/PG ratio and nicotine strength. You pay for the flavour but customise everything else. The maths is more complex than shortfills but the savings and customisation are real.

• What you get in the bottle: Concentrated flavour suspended in PG, usually 10-20ml in a 60ml or 120ml bottle.
• What you add: Base liquid (VG/PG mix) to fill the bottle, plus nic shots if you want nicotine.
• Why this format: Cheaper to ship and store (smaller bottle). Maximum flavour customisation. Multiple uses from one flavour bottle.
• Where it sits in the UK market: Smaller than shortfills but growing. Popular with experienced DIY mixers.

How to mix a longfill

1. Buy the longfill bottle

   Common: 20ml concentrate in a 60ml bottle, or 30ml concentrate in a 120ml bottle.

2. Buy base liquid and nic shots

   Base liquid: 0mg VG/PG blend in whatever ratio you want (70VG/30PG is standard). Nic shots: 10ml of 18mg or 20mg freebase nicotine.

3. Pour base liquid into the longfill

   Fill the empty space in the bottle to within 10ml of the top (for nic shot capacity later). For 20ml concentrate in a 60ml bottle, add 30ml of base.

4. Add nic shots

   Pour in your nic shot(s). One 10ml shot brings strength to about 3mg in a 60ml total liquid. Two shots make it about 5.5mg.

5. Replace cap and shake

   Close firmly and shake vigorously for 60-90 seconds. Longfill concentrates are more viscous than shortfill liquid, so they need longer mixing.

6. Let it steep

   Most longfills benefit from steeping. Let the bottle sit in a cool, dark place for 24-72 hours before using. The flavour matures and blends.

7. Test and use

   Fill your tank as usual. Taste the result. Adjust future batches based on what you learn.

The maths of a longfill

Slightly more complex than a shortfill. You need to think about the empty space and the final ratio.

Shortfills vs longfills

The two formats serve similar purposes but differ in flexibility and cost.

Steeping longfills

Steeping is letting the mixed liquid mature over time. It matters more for longfills than for shortfills because the flavour concentrate is more intense and needs to blend with the base.

• The science: Flavour compounds dissolve and integrate fully into the base liquid over time. Some compounds change chemistry slightly during steeping, often improving the flavour.
• Minimum recommended: 24-72 hours for most longfills.
• Premium recommendation: Some complex flavours benefit from 1-2 weeks of steeping.
• How to steep: Cool, dark place. Shake gently once a day. Open the cap occasionally to allow air exchange (called “breathing”).
• Steeping accelerators: Some users put bottles in a warm water bath or use ultrasonic devices. These shortcut steeping but can damage some flavour compounds. Use cautiously.
• Signs of fully steeped liquid: Slightly darker colour, smoother flavour, less “perfumy” or chemical notes.

UK longfill brands and where to find them

The UK longfill market is smaller than the shortfill market but growing. Several specialist brands focus on this format.

• Where to buy: Specialist vape shops with DIY mixing sections. Some online retailers carry comprehensive longfill ranges. Less commonly found in convenience stores.
• Brand examples: European brands like Aroma King Longfill, Doctor Vapes Longfills, and various boutique mixers dominate the UK longfill scene.
• Price range: 20ml concentrate longfills typically £10-15 in the UK. Cost effective when you consider the 60ml final volume.
• Range: Often more varied and adventurous flavour profiles than mainstream shortfills. Independent mixers experiment more.
• What to check: MHRA notification number on the packaging. Date of manufacture. Concentrate volume clearly marked.

Who should buy longfills

The bottom line