Short Fill E-Liquids and Nicotine Shots: How Do They Work Together?

Author : FogFathers London | Published On : 07 Sep 2026

Vaping e-liquids are available in different sizes, strengths, and formats. One popular option is the short fill system, which gives users more flexibility when choosing whether to add nicotine. Short fill E-Liquids are usually sold in larger bottles with some space left inside. This space is designed to allow a nicotine shot to be added.

Nicotine shots are small bottles of nicotine-containing e-liquid. When mixed with a short fill, they can provide a chosen nicotine strength while keeping the main e-liquid separate until it is ready to be used.

Understanding how these two products work together is useful for anyone who wants to know more about e-liquid mixing, nicotine levels, and the final strength of their vape liquid.

What Are Short Fill E-Liquids?

Short fill E-Liquids are larger bottles of e-liquid that are not filled completely to the top. The liquid inside is normally nicotine-free, although the exact formulation can vary.

The empty space is intentional. It gives users room to add a nicotine shot without spilling the liquid. Once the nicotine shot is added, the bottle can be closed and shaken so that the two liquids mix properly.

Short fills are available in many different flavours and PG/VG ratios. Since the nicotine is added separately, users have more control over the final nicotine level.

What Is a Nicotine Shot?

A nicotine shot is a small bottle containing a measured amount of nicotine liquid. It is designed to be mixed with a larger quantity of e-liquid.

The nicotine strength of a shot is usually shown in milligrams per millilitre (mg/ml). When the shot is mixed with a larger amount of nicotine-free e-liquid, its nicotine becomes diluted.

This means the final strength of the mixture will be lower than the strength shown on the nicotine shot. The final amount depends on the volume and strength of both liquids.

Because nicotine is addictive, nicotine-containing products should be handled carefully and kept away from children and pets.

Why Is There Empty Space in a Short Fill Bottle?

The extra space in a short fill bottle has a specific purpose. It allows enough room for the recommended nicotine shot to be added.

For example, if a bottle contains 50ml of e-liquid in a 60ml bottle, the remaining 10ml provides space for a 10ml nicotine shot. After mixing, the bottle contains approximately 60ml of e-liquid.

Without this extra space, adding another liquid could cause the bottle to overflow.

How Do Short Fills and Nicotine Shots Work Together?

The process is based on mixing two liquids together. The short fill provides the main flavour and e-liquid base, while the nicotine shot adds the nicotine.

After adding the recommended nicotine shot, the bottle should be closed securely and shaken well. This helps spread the nicotine evenly throughout the liquid.

The final nicotine strength depends on the amount of nicotine added and the total volume of liquid after mixing. This is why it is important to check the instructions before adding a nicotine shot.

Simple Example of Nicotine Mixing

Imagine a short fill contains 50ml of nicotine-free e-liquid and you add a 10ml nicotine shot containing 18mg/ml nicotine.

The total volume becomes 60ml.

The amount of nicotine added is:

18mg × 10ml = 180mg of nicotine

The final strength is:

180mg ÷ 60ml = 3mg/ml

So, the finished e-liquid would contain approximately 3mg/ml nicotine.

The exact calculation will change depending on the size and strength of the nicotine shot and the amount of short fill used.

Quick Guide to Mixing

The table below shows how the amount of nicotine can change after a nicotine shot is mixed with a larger amount of e-liquid.

These figures are examples to explain the basic dilution process. Always follow the instructions supplied with the products you are using.

Does a Nicotine Shot Change the Flavour?

Adding a nicotine shot can have a small effect on the taste of an e-liquid. The change depends on the amount of nicotine liquid added and the strength of the original flavour.

A strongly flavoured short fill may show very little difference after mixing. However, some flavours can taste slightly different once nicotine has been added.

Nicotine can also affect the throat sensation of an e-liquid. Higher nicotine levels may provide a stronger throat hit, while lower levels can feel smoother.

Shaking the bottle properly after mixing is important because it helps distribute the nicotine and other ingredients throughout the liquid.

What Happens to the PG/VG Ratio?

PG and VG are common base ingredients used in e-liquids. They affect the way an e-liquid feels and performs when used in a vape device.

When a nicotine shot is added, its own PG/VG content becomes part of the final mixture. This means the final ratio may be slightly different from the ratio of the original short fill.

For most users, this small change may not make a major difference. However, anyone who specifically chooses an e-liquid because of its PG/VG ratio should consider both the short fill and the nicotine shot when mixing.

How Should You Mix a Short Fill?

Mixing a short fill does not usually require complicated equipment, but care is important when handling nicotine-containing liquid.

The basic process includes:

• Check the short fill bottle and nicotine shot before mixing.

• Make sure the nicotine shot is suitable for the bottle and intended mixture.

• Add the recommended amount of nicotine shot carefully.

• Close the bottle tightly and shake it thoroughly.

Avoid adding more nicotine than recommended simply to increase the strength. Adding extra liquid can change the final nicotine concentration, flavour, and PG/VG ratio.

It is also important not to overfill the bottle. The manufacturer's recommended capacity should always be followed.

How Should Nicotine Shots Be Stored?

Nicotine shots should be stored carefully when they are not being used. Keep them tightly closed and away from direct sunlight and excessive heat.

Nicotine-containing liquids should also be kept out of reach of children and pets. Avoid unnecessary contact with the liquid, particularly with the eyes or skin.

If nicotine liquid is spilled on the skin, wash the area thoroughly with water. If it is swallowed accidentally or causes concerning symptoms, seek appropriate medical help immediately.

Can You Add More Than One Nicotine Shot?

Whether you can add more than one nicotine shot depends on the size of the short fill bottle and the desired final strength.

Adding another shot increases the total amount of nicotine as well as the total volume of liquid. It can also change the flavour and PG/VG balance.

For this reason, users should calculate the final strength before adding additional nicotine. Simply adding more shots without checking the final concentration can result in a mixture that is stronger than intended.

What Are the Main Benefits of the Short Fill System?

The biggest benefit of short fills is flexibility. Instead of purchasing a bottle with a fixed nicotine strength, users can add nicotine separately according to their needs.

Other advantages include:

• Larger bottles can provide more e-liquid for regular users.

• Nicotine can be added separately rather than being present from the start.

• The final nicotine strength can be calculated based on the amount added.

• Different flavours and nicotine shots can offer more choice.

However, short fills may not be ideal for people who prefer e-liquids that are already mixed and ready to use.

How Long Does Mixed E-Liquid Last?

The quality of e-liquid can change over time, especially when it is exposed to heat, sunlight, or air. Once a nicotine shot has been mixed into a short fill, keep the bottle closed when it is not being used.

Store the finished e-liquid in a cool, dry place away from direct sunlight. Always check the product's use-by information and storage instructions.

Changes in colour or flavour can happen over time, but any unusual change should be treated carefully and checked against the manufacturer's guidance.

Final Thoughts

Short fill E-Liquids and nicotine shots are designed to work together through a simple mixing and dilution process. The short fill provides the main e-liquid and flavour, while the nicotine shot adds a measured amount of nicotine. The space in the bottle makes room for the shot to be added.

Understanding the final nicotine strength is important because the nicotine becomes diluted when it is mixed with the larger amount of e-liquid. Following the mixing instructions, calculating the final strength, and shaking the bottle properly can help create a consistent mixture.

For anyone exploring different e-liquid options, FogFathers offers a range of choices to help users find products that suit their vaping preferences. Always handle nicotine products responsibly and follow the instructions provided with the products.