Longfill

What are longfills?

Longfills are a popular format for vapers who want greater control over their e-liquid. A longfill consists of a bottle containing a concentrated flavor with space left to add neutral base liquid and optional nicotine shots. This makes it possible to customize both nicotine strength and VG/PG ratio while keeping the mixing process straightforward.

How longfills work

Each longfill bottle contains a measured amount of flavor concentrate, commonly 20ml or 30ml, inside a larger bottle. The remaining space is intended for base liquid and nicotine shots. Because longfills are sold without nicotine, they allow users to fine-tune their preferred strength, whether that means gradually reducing nicotine or maintaining a specific level. This format is widely used across the longfill category and suits both new and experienced DIY mixers.

Longfill bottle sizes and formats

Longfills are available in various bottle sizes, such as 60ml, 100ml and 120ml. The amount of flavor concentrate typically represents around 10–30% of the final volume, depending on the brand and recipe. This approach provides a consistent flavor base while still allowing adjustments to the final mix. Many well-known brands, including IVG longfills and Just Juice longfills, use this format.

Why choose longfills?

Longfills offer flexibility that ready-made e-liquids cannot. Since nicotine is added separately, users have full control over the final strength. The higher concentration of flavor also allows for more complex and layered profiles. In addition, because longfills are sold as nicotine-free products, they are typically compliant with TPD regulations, giving manufacturers greater freedom in flavor development.

How to mix a longfill

Mixing a longfill is a simple process. Add the desired number of nicotine shots to the bottle, then top up with neutral VG/PG base liquid until the bottle is full. Shake thoroughly to ensure the mixture is evenly combined. Base liquid used for mixing can be found in the base liquid category.

Frequently asked questions

Can longfills be used without mixing?
No, longfills are concentrated flavors and must always be mixed with base liquid before use.

How strong will the nicotine be?
The final nicotine strength depends entirely on how many nicotine shots you add and the final bottle volume.

Do longfills require steeping?
Many longfills can be used shortly after mixing, but some flavors benefit from a short resting period to allow the profile to settle.

Are longfills suitable for beginners?
Yes, longfills are often considered one of the easiest ways to start DIY mixing, as they require minimal measuring and preparation.