Why Candles Tunnel and How to Fix It

Why candles tunnel, and how to stop it

A candle tunnels when its first burn was too short. Living Light says a first burn needs three to four hours to create a large enough hole to "set the memory", and every burn after that follows the same track. Get it right once and the candle burns to the edge; get it wrong once and it never will.

Last checked 15 September 2026 against Living Light Candles

Updated 15 September 2026 · About 5 minutes to read · Written by NZ Candles

What is tunnelling?

The flame melts a narrow shaft straight down the middle of the candle and leaves a wall of unburnt wax around the edge of the jar. The candle looks half full and behaves as if it is nearly finished: the wick drowns in its own well, the scent stops carrying, and the wax around the rim is never coming back. On a $58 candle with 65 stated hours, a tunnel can easily cost you a third of what you paid.

What causes it?

The first burn, in almost every case. Living Light's care page is the clearest New Zealand statement of it we found: "When burning a candle for the first time, burn it long enough to create a large hole. Depending on the type of candle, the time will vary between 3–4 hours. This will then set the 'memory'." Wax has a memory of the pool it made last time, and it will not go wider than that pool without help.

Two other things make it worse. A long wick makes a tall, flickery flame that burns down rather than out — Living Light says to keep the wick trimmed to 5mm, and the National Candle Association says ¼ inch, before each use. And draughts: the NCA says to avoid open windows, fans and air vents, which push the flame to one side and melt the wax unevenly.

How to stop a candle tunnelling

Trim before you light it
5mm, says Living Light. ¼ inch, says the National Candle Association. Same rule, and it applies before every burn, not just the first.
Clear the draughts
The NCA says to keep candles away from open windows, fans and air vents. A candle burning next to an open window in a Wellington southerly is going to tunnel.
Give the first burn 3 to 4 hours
Living Light's figure, and the whole ballgame. Don't light a new candle if you're going out in an hour — light one you've already burnt properly.
Let the pool reach the edge before you put it out
This follows from the memory rule: the pool you set on the first burn is the widest that candle will ever go.
Stop before the jar runs dry
Living Light says 1cm from the bottom for a soy candle in a jar; the NCA says half an inch of wax remaining. Not a tunnelling rule, but the other end of the same instruction.

Can you fix a candle that's already tunnelling?

The fixes that circulate online — wrapping the jar in foil, or running a hairdryer over the surface to re-level the wax — are widely repeated but we could not find them in any maker's or safety body's published advice, and both involve adding heat to a lit or recently lit candle. So we're not going to tell you to do either.

What we can say safely: give it the longest uninterrupted burn you reasonably can, with the wick trimmed and no draught, and accept it may not fully recover. And if the tunnel appeared on the very first burn despite a proper three-to-four-hour session, that is not user error — see below.

When is tunnelling a fault you can return?

If a candle tunnels badly on a correct first burn, the likely cause is a wick that is too small for the diameter of the vessel — a manufacturing choice, not something you did. Under the Consumer Guarantees Act, goods sold in New Zealand must be of acceptable quality and fit for their ordinary purpose. A candle that cannot burn to the edge of its own jar is arguably neither, and you can ask the retailer who sold it to you for a repair, replacement or refund. Consumer Protection sets out how those rights work.

Frequently asked questions

How long is the first burn meant to be?

Three to four hours, says Living Light, depending on the candle — long enough to create a large melt pool that sets the candle's memory.

Can I fix a tunnelled candle with foil or a hairdryer?

Those tricks are all over the internet but we could not find either in any maker's or safety body's published advice, and both add heat to a candle. We're not recommending them. Try a long, draught-free burn with a trimmed wick instead.

Does trimming the wick really matter?

Both sources we use say so. Living Light says trim to 5mm before and during burning; the National Candle Association says trim to ¼ inch before each use "to prevent high flames and soot". A tall flame burns down, not out.

Do some waxes tunnel more than others?

We could not source a comparison. Melting point differs — container soy around 45–52°C, beeswax around 62°C on one supplier's specs — and a harder, higher-melting wax plausibly takes longer to pool, but nobody publishes tunnelling rates by wax and we won't invent one.

Is a tunnelled candle dangerous?

The specific risk the National Candle Association addresses is a tall flame, which is what an untrimmed wick in a deep tunnel produces. Its rules still apply: never leave it unattended, keep it 12 inches from anything flammable, and stop burning when half an inch of wax remains.