What is a longfill? The DIY-lite bottle explained

A shortfill is complete liquid with a gap for nicotine. A longfill is mostly gap. The bottle contains a small amount of concentrated flavour, sometimes called a one-shot, and you fill the rest with unflavoured VG/PG base and nicotine shots.

Sizes vary by brand. You might see 10ml to 30ml of flavour in a 60ml or 120ml bottle, and the label will say how much to fill up to. The concentrate is strong on purpose, because it is going to be diluted several times over.

The appeal is control. You decide the nicotine strength and, by choosing your base, the final VG/PG ratio too.

Think of the three as a ladder of effort. Shortfills ask you to add a shot and shake. Longfills ask you to add shots and base, then let the bottle sit for a while. Full DIY asks you to buy individual flavour concentrates and work out percentages from scratch.

Longfills give you most of the flexibility of DIY with almost none of the recipe work, since the flavour balance has already been done by the maker. The trade-off is a few extra minutes and, ideally, a little patience while it steeps. The DIY tools you might want, from bottles to syringes, are under DIY e-liquid accessories.

Read the label first. Every longfill states the total volume to fill to, and some suggest a VG/PG ratio for the base. Going over or under changes how strong the flavour tastes, so follow it unless you have a reason not to.

Add the nicotine shots before the base. That way you know exactly how many shots went in, and you top up to the line with base afterwards. Shake hard, then leave the bottle somewhere dark at room temperature. Concentrated flavours tend to blend better with time, so many vapers wait a few days before tasting properly.

Here is where longfills beat shortfills. Because the bottle is mostly empty, you can add as many shots as you like and simply use less base. In a 60ml longfill with 20ml of flavour, one 18mg shot gives 3mg, two give 6mg, three give 9mg.

That makes longfills useful for MTL tank users who want a big bottle at 6mg or more, something a 50ml shortfill can only manage with an overflowing bottle and washed-out flavour. Nicotine is addictive, so the ability to go higher is a convenience, not a recommendation.

Longfills suit people who already buy shortfills, like the idea of choosing their own strength and ratio, and do not mind a short wait. They are less suited to anyone who wants to open a bottle and vape straight away.

If you are on a small MTL pod and need 10mg or 20mg, a ready-made 10ml nic salt is simpler. If you are on a big tank at 3mg, a shortfill will do the job with less fuss. Longfills shine in the middle: MTL and restricted-lung tanks at 6mg to 12mg.

The biggest one is vaping the concentrate neat, either by accident or out of curiosity. It is many times stronger than finished liquid, tastes harsh and can be hard on your coil. Always dilute it first.

The others are smaller but common: filling past the stated volume and wondering why it tastes of nothing, forgetting to count shots, and judging the flavour five minutes after mixing. Keep concentrate, shots and base capped and stored away from children and pets. A strip of masking tape on the bottle with the date and strength saves a lot of guesswork later.