How to stop a candle tunnelling

Tunnelling is when a candle burns straight down the middle and leaves a thick wall of unburned wax around the edge. It wastes wax you paid for, it buries the wick, and eventually the flame drowns in its own pit. It is also almost entirely preventable.

Why candles tunnel

Wax has memory. The first time you burn a candle, the melt pool you create sets the pattern for every burn after it. If you blow the candle out while only the centre has melted, the next burn will follow that same narrow channel, and the one after that will dig it deeper.

So tunnelling is rarely a fault in the candle. It is usually a first burn that ended too soon.

The first burn rule

Light your candle and leave it burning until the melted wax reaches the edge of the vessel, a full melt pool from side to side. For a Limewick Personal candle (155g in a cast-stone vessel), allow roughly two to three hours for this. Plan the first light for an evening when you will be in the room anyway.

Do that once, and the candle will tend to burn flat and even for the rest of its life.

Habits that keep it burning evenly

Trim the wick to about 5mm before each burn. A long wick makes a tall, hungry flame that burns hot and fast down the centre. Trimmed, the flame stays low and spreads its heat outward.

Burn in sessions of one to four hours. Under an hour rarely reaches a full melt pool. Much over four and the wick can start to mushroom and smoke.

Keep the candle out of draughts. A draught pushes the flame to one side, melting one edge and neglecting the other, which is tunnelling's lopsided cousin.

How to fix a candle that has already tunnelled

If the tunnel is shallow, one long burn of three to four hours will often let the pool catch up and level the surface.

For a deeper tunnel, use the foil method. Wrap a strip of kitchen foil around the top of the vessel, leaving a hole in the middle for the flame to breathe. The foil reflects heat back onto the stubborn wax wall, melting it into the pool. Twenty to thirty minutes usually shows visible progress. Stay in the room while you do this, and mind the foil when removing it, as it gets hot.

As a last resort, you can carefully remove soft wall wax with a spoon after a burn while it is warm, then let subsequent full burns re-level the surface. Any wax you remove is not wasted if you have a wax burner; it will melt down like a wax melt.

A small advantage of coconut wax

Coconut wax melts at a lower temperature than paraffin, so the pool spreads to the edge more readily and full melt pools come easier. It does not make a candle immune to tunnelling, but it makes good habits go further. There is more on getting the best from a burn in our Burn & Care guidance.

And if you are starting fresh, give the first burn of something like Clean Luxe the evening it deserves. The whole range of coconut wax candles follows the same rules: one patient first burn, a trimmed wick, and no draughts.