Why Does My Candle Tunnel, Flicker or Smoke? 8 Fixes

Updated 27 October 2026

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Written by IVNA London

Most candle problems come from two things: a first burn that was too short, and a wick that was not trimmed. Let the first burn melt the wax right to the edge, trim the wick to about 5mm every time, and keep the candle out of draughts.

What is the first burn rule?

Wax has a "memory", so on the first burn you want the melted pool to reach the edge of the jar, which can take two to three hours for a standard candle. If you blow it out early, it will tunnel down the middle from then on. A well made candle helps too, so see our guide to the best luxury scented candles.

Why does a candle tunnel?

Tunnelling can happen to any candle at any price, and it happens because the flame was put out before the melted wax reached the sides of the jar. Next time you light it, the wax tends to melt only as far as it did last time. Each short burn leaves a ring of hard wax around the edge, so the flame sinks deeper into the middle and a thick wall of good wax is left unused.

A simple guide for the first burn is about one hour for every 2.5cm across the top of the jar, so a jar about 7.5cm wide needs roughly three hours. The real test is what you can see: a clear pool of melted wax that runs right to the glass all the way round.

So light a new candle on a quiet evening at home, and follow the same rule on every burn after that. Wick size matters too, because a wick that is too small for its jar cannot melt the wax to the sides, however long it burns.

What are the 8 common problems and fixes?

1. Tunnelling

Cause: a first burn that stopped before the wax reached the edge. Fix: wrap foil around the rim, leaving a hole over the middle, and burn until the wax levels out.

2. Black smoke

Cause: a wick that has grown too long, or a draught from a door or window. Fix: put it out, let it cool, trim to 5mm and move it away from draughts.

3. Flickering flame

Cause: draughts, a long wick or air currents from doors and fans. Fix: trim the wick and move the candle somewhere the air is still. Laboratory tests have found that flickering flames can make several times more soot than steady ones.

4. Flame keeps going out

Cause: the wick is drowning in wax, or it has been trimmed too short to hold a flame. Fix: put the flame out, let the candle cool and set, then lift out a little of the excess wax with a spoon before relighting, and never pour hot wax.

5. Mushrooming wick

Cause: carbon build up, which often means the candle has burned for too long in one go. Fix: trim the black "mushroom" off with scissors or a wick trimmer before lighting, and follow the length on the label.

6. Black marks on the jar

Cause: soot from a wick that has grown too long, or a flame that keeps flickering. Fix: trim the wick, then wipe the cooled jar with a damp cloth and a drop of washing up liquid.

7. Weak scent

Cause: the melt pool is not full, or the room is big and draughty. Fix: burn for two to three hours with the door closed so the scent can build up, and see which candles have the strongest scent.

8. Burnt smell

Cause: a wick that is too long, or burning the candle too near the bottom of the jar. Fix: trim the wick before you light it, and stop when about 1cm of wax is left.

What is the best way to put a candle out?

Blowing a candle out is quick, but it sends up smoke that smells of burnt wick and spoils the scent you have built up. A candle snuffer is a small bell on a handle that you hold over the flame, so it goes out gently with almost no smoke. A wick dipper is a thin metal hook that pushes the lit wick into the melted wax and lifts it straight back up. The wick gets a coat of wax that helps it light cleanly next time, so check it stands straight in the centre before the wax sets.

Where should you put a burning candle?

Stand the candle on a flat, heatproof surface like a stone coaster, because the jar gets hot and a level base helps the wax melt evenly. Keep it away from open windows, doors, fans and radiators, where moving air makes the flame dance and smoke. Give it space from walls and curtains too, as soot can mark paintwork. When about 1cm of wax is left, the candle is finished, because burning any lower can overheat the glass.

How do you care for a candle every day?

Trim the wick to about 5mm before each burn, once the wax has set.
Burn for no more than 4 hours at a time, then let it cool fully before you relight.
Keep it away from draughts, curtains and anything that can catch fire.
Never leave a candle burning unattended, and always put it out before you go to sleep or leave the house.
Keep it out of reach of children and pets.

How long should I burn a candle the first time?

Burn it until the wax melts to the edge, which often takes two to three hours depending on the jar width, and see how long a candle burns.

Quick answers

Can you fix a tunnelled candle?

Yes, often, if you use the foil trick and let it burn until the surface is level again.

Why does my candle burn unevenly?

It is usually draughts or a wick that has drifted off centre, so move it and straighten the wick while the wax is soft.

Why does my candle dip in the middle?

That is tunnelling, which comes from a short first burn, so see fix 1 above.

Is it better to blow out or snuff a candle?

Snuffing or dipping the wick is better, because blowing it out makes more smoke and can splash wax.

How short should I trim my wick?

About 5mm suits most jar candles, but follow the maker's label, because a wick cut much shorter can leave a flame too small to melt the wax to the edge.

Browse our luxury scented candles, and you will find care instructions with each one.

Our candles

Every IVNA London candle comes with the same care steps on its product page: melt to the edge on the first burn, trim to 5mm, and burn for no more than four hours. Browse the Kew Morning, Belgravia Linen, Mayfair Library and Hampstead Spa scented candles. They are vegan, with no palm oil, and are made to EN 15426, EN 15493 and BS EN 15494.

For a quiet evening first burn, Mayfair Library fills the room with warm vanilla, tonka and cedarwood.