How to prevent and correct candle tunnelling

Candle tunnelling is a common but preventable problem that occurs when a candle isn't burned properly. When a candle is lit and subsequently blown out before it has had the chance to burn to the edges of the vessel, it leaves a ledge of solid wax. This then causes the flame of the wick to create a vertical “tunnel”.

Within the tunnel, the wax directly underneath the flame will quickly melt, while the surrounding wax will remain solid. This causes the tunnelling to worsen over time. Once the wick descends deeper into the surrounding wax, the flame won’t be able to get enough oxygen to sustain itself, causing the candle to go out. At this point, it is hard to correct the tunnelling.

What are the main causes behind tunnelling?

Having a good understanding of what causes your candles to tunnel, will help you prevent it in future. Two of the most common causes of candle tunnelling are highlighted below.

• Incorrect burn: tunnelling most commonly occurs when a "memory ring" has formed in the wax of the candle. Memory rings form when the candle has not burned for long enough, preventing it from burning to the edge of the candle vessel.
• Incorrect wick size: another cause of tunnelling is having a wick that is too small for the volume of wax or the width of your vessel. A wick which is too small may, despite its best efforts, not have enough power to burn the wax from edge to edge.

How to prevent candle tunnelling:

The best way to prevent your candle from tunnelling is to burn it correctly from the very first burn, which means ensuring you allow the wax to fully melt to the edge of the candle vessel, both on the first burn and every consecutive burn after!

How long that takes depends on the size of your candle. However, a good rule of thumb to remember is that you should burn your candle for at least 1 hour and no more than 4 hours every burn.

How to fix candle tunnelling:

Option 1: The heat gun method

The first method requires an external heat source (a heat gun is ideal, but a hair dryer can also work) to melt the solid wax around the edges of the candle vessel. This "resets the memory" of the wax, widening the melt pool that reaches all the way to the edges.

For your safety, especially if you're doing this for the first time, make sure you're wearing protective eye gear and clothes that can be washed.

When using the heat source, avoid turning it on directly over the candle - hold it far away and slowly move it closer to an appropriate distance in order to avoid blowing melted wax.

Steps:

1. Trim the wick and remove any debris inside the tunnel
2. Using a heat gun (or hair dryer), gently heat the surface of the candle from an appropriate distance
3. Continue heating until the entire surface of the candle has completely melted and smoothed over. This may take several minutes depending on how high your heat source is
4. Once the wax has set, relight your candle and allow it to burn for at least 1 hour, or until you can no longer see any tunnelling.

Option 2: The foil technique

The second method uses aluminium foil to cover the top of the candle, which then allows the candle to retain its own heat in order to melt the extra wax that surrounds the edges of the vessel.

Steps:

1. Trim the wick and remove any debris inside the tunnel
2. Fold a piece of aluminium foil in half and wrap it around the top of the candle, making sure to maintain an opening at the top of the candle for the flame
3. Allow it to burn for at least 2 hours, or until you can no longer see any tunnelling
4. Remove the aluminium foil and continue to burn your candle, or set your candle aside to let the wax set. 

Please note: If your flame goes out when you put the foil on, this means you need to widen the opening of the foil at the top of the candle where the flame is. 

We hope that with all this information, we have provided adequate knowledge to help you maintain your beautiful candle! At Theia Fragrances, our aim is to create memories and experiences through our unique scents without compromising on the quality of our candles! This is why we put extensive research into the products we use before making an informed decision. As always, if you have any questions, please do not hesitate to contact us here.