Understand the phenomenon and avoid it for good
You light your candle. The ambiance is perfect. Then, a few hours later, you look at the jar… and there’s a hole in the center. The edges are intact. The wax seems wasted.
Welcome to the world of tunneling.
It’s one of the most common problems with a scented candle. The good news? It’s neither mysterious nor irreversible.
We will see clearly:
- why a candle tunnels
- how to properly burn your candle from the start
- and how to fix a candle that has started to tunnel
What exactly is tunneling?
Tunneling occurs when the flame digs a hole downwards without melting the wax to the walls of the jar. Result:
- the candle only burns in the center
- the sides remain full
- lifespan decreases and you lose a good part of your wax
It’s not an aesthetic defect. It’s a combustion issue.
Why does a candle tunnel?
1. The first use is too short
This is THE number one cause.
Wax has a memory. If you extinguish your candle before the entire surface has melted for the first time, it will continue to burn at the same diameter afterward. It reproduces the initial “trace.”
If the first melt stops in the center, the tunnel begins.
2. A wick that is too small for the diameter
If the wick is not powerful enough to heat the entire surface, the wax will never melt to the edges.
This often happens with poorly calibrated industrial candles… or wicks that are not suited to the wax used.
3. Drafts
An unstable flame produces less heat.
A candle placed near a window, fan, or hood can tunnel instead of melting evenly.
4. A cold surface or a thick container
Ceramic or thick glass containers absorb heat. At first, the flame has to work harder to heat the walls. If you extinguish it too early, the tunnel starts.
How to properly burn your candle to avoid tunneling
Here are the simple rules. Not complicated. Just effective.
1. Always let it melt to the edge during the first burn
This is the golden rule.
In general, count about 1 hour per inch of diameter.
A candle 3 inches wide? Minimum 3 hours.
So for our Coral Cotton rechargeable candle (200g) which has a diameter of 3.4", we recommend letting it burn between 3 and 4 hours.
The surface should be completely liquid, from edge to edge.
2. Trim the wick before each use
A wick that is too long gives an unstable flame.
A wick that is too short gives a weak flame.
The ideal length: about 5 mm (¼ inch).
This allows for stable and sufficiently hot combustion.
3. Burn in chunks of 3 to 4 hours
Burns that are too short encourage tunneling.
Burns that are too long tire the wick.
The balance is found between the two.
4. Avoid drafts
A constantly dancing flame does not heat evenly.
Place your candle on a stable surface, away from drafts.
How to fix a candle that has tunneled
Good news: it's not lost.
Method 1: the aluminum foil technique
Simple and effective.
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Light the candle.
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Wrap the top of the jar with aluminum foil.
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Leave an opening in the center for the flame to breathe.
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Let it burn for 1 to 2 hours.
Heat will accumulate and melt the wax left on the walls.
You recreate a uniform surface.
Method 2: remove excess wax
If the tunnel is very deep:
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Extinguish the candle
-
Gently scrape a bit of wax around the wick
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Restart a long and complete burn
This helps the flame regain strength.
Method 3: patience
The lower the flame goes in the container, the more heat concentrates.
Sometimes a candle corrects itself after a few long burns.
Does tunneling mean that the candle is of poor quality?
Not necessarily.
Even a handmade candle, even a soy wax candle, can tunnel if the first use was too short.
The quality of the wick and the formulation plays a role, yes.
But usage is key.
A well-maintained candle can burn cleanly until the last drop.
If you use rechargeable candles, these rules are even more important. A good first burn ensures that your jar will stay pristine for your next refill.
Taking care of your candle is not complicated.
It's just understanding how it works.
