WHAT DOES “CANDLE TUNNELING” MEAN?
Tunnelling happens when only a small portion of the wax around the wick melts while the candle is burning.
Instead of having the entire surface of the wax melt evenly, it will appear as though the flame is burrowing into the candle and creating what resembles a small, vertical tunnel — hence the name.
Inside the tunnel, the wax directly underneath the flame quickly melts into liquid while the surrounding wax remains hard. This causes the tunnelling to become worse 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.
But the problem doesn’t stop there. Tunnelling is bad because it can drastically reduce the total burn time of your candle.
Normally, burn time is based on the total volume of wax in the container — in general, bigger candles have longer burn times. But when candle tunnelling happens, only a fraction of the wax is actually used up before the wick reaches the bottom.
As a consequence, all of the remaining wax — and the luxurious fragrances contained within — that makes up the hard, outer ring surrounding the tunnel is sadly wasted.
WHY DOES TUNNELING HAPPEN?
People sometimes mistake tunnelling as an issue of candle quality.
It’s true that tunnelling is more likely to occur in cheap candles compared to higher quality luxury candles. However, the truth is that tunnelling can happen to ANY candle — even the most expensive ones.
There are two main causes of candle tunnelling:
- Poor candle burning habits
- Improperly sized wicks
In this context, poor candle burning habits refers specifically to the "first burn," or the first time you burn the candle.
At the Chantic, we always emphasize how important it is to burn the candle long enough to let the entire surface of the candle melt before blowing or snuffing it out. This usually takes at least an hour or two, depending on the size of the candle.
If you don’t do this, you’re almost guaranteed to get tunnelling
Why? That’s because wax contains a certain amount of “memory.”
Wax isn’t always as “hard” as it seems. Even in its solid state, wax will continue to harden over time. Candle wax that was melted and cooled again yesterday will always be softer than candle wax that has been sitting around for a week.
So, if on the first time, you only let the wax in the centre melt before blowing the candle out, on the second time you burn it, only that small centre portion of wax will continue to melt. That’s because it’s “softer” than the wax around it and therefore requires less thermal energy to melt again. The surrounding wax that didn’t melt the first time is “harder” in comparison, so it won’t melt and voila — you have tunnelling.
The other cause of candle tunnelling is when the wick is too small for the size of the candle.
If the wick is too small, it might not be able to generate enough heat to melt the wax all the way at the edge of the candle. As a result, even if you give your candle plenty of time on the first burn, you may still end up getting tunnelling.
This is a problem with the design of the candle, which is why tunnelling is more common in the mass-produced candles that use cheaper wicks. The more expensive, luxury candles are usually designed with more care, making sure that the wicks are of higher quality and properly sized to the diameter of the candle.
But again, tunnelling can still happen in even high-end candles if you don’t burn them properly. Make sure you allow enough time on the first burn to melt the entire surface evenly.
HOW TO FIX CANDLE TUNNELING
What should you do if your candle has already started tunnelling?
Don’t panic; you can still salvage it! By understanding what causes tunnelling, you can naturally reverse the situation and save your candle.
In order to fix candle tunnelling, all you need to do is melt the outer wax surrounding the tunnel and make the surface even again.
We recommend 2 ways to do this:
OPTION 1: THE HAIR DRYER METHOD
- Trim the wick and remove any debris inside the tunnel.
- Using a heat gun (if you have one) or hair dryer on the highest setting, heat the wax on the top surface of the candle.
- You can carefully poke at the solid wax on the sides with a toothpick to help it melt faster.
- Continue heating until the entire top surface of wax has completely melted and smoothed over.
- Relight your candle and allow it to burn for at least 30 minutes or until you can no longer see any tunnelling.
- Set your candle aside and let the wax harden over the next few days. Depending on the type of wax used in your candle, it can take between 2 days (paraffin) to 2 weeks (soy, coconut) for your wax to reach full hardness.
OPTION 2: THE ALUMINUM FOIL METHOD
- Trim the wick and remove any debris inside the tunnel.
- Cover the top of the candle with aluminium foil.
- Cut a small opening (around 1-inch) in the centre of the aluminium foil.
- Remove the aluminium foil, light the wick, then place the foil cover back on.
- Allow the candle to burn for a few hours until the top surface of wax has completely melted and smoothed over.
- Set your candle aside and let the wax harden over the next few days to reach full hardness (see above).
HOW TO PREVENT TUNNELING WHEN BURNING YOUR CANDLES
The best way to fix candle tunnelling is to prevent it from happening in the first place. And it’s very simple, too.
To prevent tunnelling, all you need to do is burn your candle long enough each time so that the entire top surface of wax is melted. This is especially important the first time you burn your candle!
How long that takes depends mostly on the size of the candle. A good rule of thumb to remember is that you should burn your candle for one hour per every inch of its diameter. If your candle has a diameter of 3 inches, you should plan to let it burn for 3 hours before putting it out.
And that's it! We hope this guide to fixing and preventing candle tunnelling will help you enjoy candles that last longer and burn more beautifully.