Why Is My Candle Smoking? 7 Common Causes of Black Smoke and Soot (and How to Fix Them)
You light a candle, settle down for the evening, and a few minutes later you notice a thin trail of dark smoke rising from the flame. Perhaps there is a grey ring forming around the rim of the jar, or a faint smudge on the wall behind it. It is a common candle question, especially once the evenings draw in and candles come out every night.
So, why is my candle smoking? The short answer is that a smoking candle is usually getting more fuel than its flame can burn cleanly. The most common causes are a wick that is too long, a draught making the flame flicker, or a candle that has been burning for too long. In most cases, putting the candle out, letting it cool, trimming the wick to 5mm and moving it out of the draught fixes the problem.
This guide explains what causes a candle to smoke, why a candle gives off black smoke or leaves soot on the jar and walls, the quick fixes that work, and when it is time to stop using a candle altogether.
Why is my candle smoking? The quick answer
A candle flame burns melted wax that travels up the wick. When the flame is calm, steady and teardrop-shaped, that fuel burns away almost completely. When something upsets that balance, some of the fuel doesn't burn fully and escapes as smoke and tiny particles of soot. That's what you see as black smoke, and what builds up as dark marks on the container.
Here is a quick checklist to run through if your candle is smoking:
- Is the wick longer than about 5mm? Put the candle out, let it cool and trim it.
- Has the wick "mushroomed"? A blob of carbon on the tip makes the flame bigger. Trim it off once the candle is cool.
- Is the flame flickering? Look for draughts from windows, doors, radiators, fans or people walking past.
- Has it been burning for more than 4 hours? Put it out and let it cool completely.
- Is there debris in the wax? Remove matches, wick trimmings or dust once the wax has set.
- Is the candle nearly finished? Stop when about 1cm of wax is left.
- Is the smoke only there when you blow it out? A short wisp then is normal (more on that below).
What causes a candle to smoke?
1. The wick is too long
This is the number one reason a candle smokes. A long wick draws up more melted wax than the flame can burn cleanly, so the flame grows tall and starts to give off smoke. That's why every one of our candles comes with the same instruction: trim the wick to 5mm before each use. If you only change one habit, make it this one.
2. The wick has "mushroomed"
After a long burn, carbon can build up on the tip of the wick and form a little mushroom shape. This makes the flame larger and less steady, and it is a classic cause of black smoke. Let the candle cool fully, then snip or gently pinch off the blackened tip before you light it again.
3. Draughts are making the flame flicker
A flickering flame is a smoky flame. When air moves around a candle, the flame dances and stretches, and it can't burn its fuel evenly. In autumn and winter the usual culprits are open windows, gaps around doors, radiators and heaters underneath a shelf, ceiling fans and busy hallways. If you've been wondering why your candle is flickering so much, a draught is the most likely reason. Move the candle somewhere sheltered and the flame should settle.
4. The candle has been burning for too long
We recommend burning our candles for no more than 4 hours at a time. Beyond that, the wick tends to mushroom, the melt pool gets very deep and hot, and the container heats up, all of which make smoking more likely. Our guide on how long you should burn a candle has burn times for tins, jars, pillars and tealights.
5. Something has fallen into the wax
Bits of match, wick trimmings, dust or even a stray bit of decoration can act like a second wick, flaring up and smoking. Once the candle is out and the wax has set, lift any debris out. Keeping the lid on between uses helps, and it keeps dust off too.
6. The candle is nearly finished, or has tunnelled
When a candle burns right down, or burns a narrow tunnel down the middle, the flame ends up sitting low inside the container. Less fresh air reaches it, so it can flicker and leave soot on the sides. Stop using a candle when about 1cm of wax remains. If your candle has tunnelled, our guide on how to stop candle tunnelling explains the causes and the safe ways to put it right.
7. The wick was trimmed or lit unevenly
A wick that leans to one side or has been cut at an angle can produce a lopsided flame that smokes and blackens one side of the jar. Trim it straight across, and before you next light it, check that the wick is standing upright in the centre.
Why is my candle smoking black?
If your candle flame is smoking black, you're seeing soot: tiny particles of carbon from fuel that hasn't fully burned. It is a sign the flame is too big or unsettled, rather than a feature of a particular wax or fragrance. Any candle can smoke if the wick is too long or it sits in a draught. A well-trimmed wick and a steady flame are what keep things clean.
If your candle is still smoking black after you've trimmed the wick and moved it away from draughts, put it out and stop using it. If it is one of ours, get in touch with us at info@hampshirecandles.com and we'll be happy to help.
Is it normal for a candle to smoke when you blow it out?
Yes. A short wisp of white or grey smoke when you put a candle out is normal. It is just the hot wick cooling down. To keep it to a minimum:
- Use a candle snuffer rather than blowing hard, which can also splash hot wax.
- Don't use water to put a candle out, as it can make hot wax spit and may crack a glass jar.
- Pop the lid back on once the candle has cooled to keep dust out.
How to stop your candle smoking
Follow these steps and most smoky candles will be back to a calm, steady flame:
- Put the candle out and let it cool and set completely.
- Trim the wick to 5mm, removing any mushroomed or blackened tip.
- Clear any debris from the surface of the wax.
- Move it out of draughts, away from windows, doors, fans, radiators and busy walkways.
- Relight it on a level, heat-resistant surface, and let the melted wax reach the edge of the container on the first burn.
- Burn for no more than 4 hours at a time, then repeat the trim before you next light it.
Our tins, like the Fresh Linen Candle Tin and the New Forest Walk Tin Candle, are hand-poured in Hampshire with a cotton wick, and the "How To Use" section on every product page gives the same simple routine.
Browse the Full Range of Scented Tin Candles
How to clean soot off a candle jar or tin
If a smoky burn has left a dark ring around the rim of your candle, wait until the candle is out and completely cool. Then gently wipe the inside rim with a dry or slightly damp soft cloth or a piece of kitchen roll, taking care not to drop anything into the wax. Make sure everything is dry before you light it again. Glass jars, like our A Hug In A Jar Candle Jar, are easy to wipe clean this way.
Grey or black marks on a wall or ceiling above where a candle stands are a sure sign the flame has been smoking. Fix the cause (usually the wick or a draught) and choose a different spot.
Why is my candle warmer smoking?
A candle warmer heats the wax from above or below without lighting the wick, so it shouldn't produce smoke from a flame. If your candle warmer is smoking, or you see smoke from a candle sitting on one, switch it off at once, let everything cool and check the instructions supplied with it. Our guide to candle warmers explains how they work.
Want fragrance without a flame?
If you'd rather not deal with wicks, trimming or smoke at all, wax melts are a lovely alternative. They're warmed in a burner rather than lit, so there's no wick to trim. Our wax melts are handmade in the UK using 100% soy wax and premium fragrance oils, and an electric wax melt burner warms them without a tealight. New to them? Our Wax Melts 101 guide covers the basics.
Candle safety reminders
- Never leave a burning candle unattended, and put it out before you leave the room or go to bed.
- Burn candles on a heat-resistant, level surface, away from draughts, curtains, decorations and anything flammable.
- Keep candles out of the reach of children and pets.
- Tins and jars get hot during use, so let them cool completely before moving them.
- If a flame becomes very large, smokes heavily or won't settle, put it out.
Always read and follow the safety information supplied with each candle. The London Fire Brigade has more advice on using candles safely at home.
Why is my candle smoking? FAQs
Why does my candle smoke so much?
Heavy smoke usually means the wick is far too long or has mushroomed, or the candle is in a strong draught. Put it out, let it cool, trim the wick to 5mm and move it somewhere sheltered. If it still smokes heavily, stop using it.
Why does my candle flicker so much?
Flickering is almost always caused by moving air from windows, doors, fans, radiators or people walking past. A long wick can also make the flame unsteady. Trim the wick and find a calmer spot.
Is black smoke from a candle bad?
Black smoke is soot from fuel that isn't burning fully. It can mark jars, walls and ceilings, and it is a sign the candle isn't burning as it should. Put the candle out and fix the cause before relighting it.
How do you trim a candle wick without a trimmer?
Wait until the candle is out and cool, then use clean, sharp scissors or nail clippers to cut the wick to 5mm. Lift any trimmings out of the wax so they don't catch light next time.
Why does my candle smoke when I first light it?
A little smoke for the first few seconds is common while the flame settles. If it keeps smoking, the wick is likely too long or has a carbon tip left from the last burn, so put it out, let it cool and trim it.
Should my candle be smoking?
No. A lit candle should burn with a calm, steady flame and little or no visible smoke. A short wisp when you light it or put it out is normal, but constant smoke means something needs fixing, usually the wick length or a draught.
Should I stop using a candle that keeps smoking?
If it still smokes after you've trimmed the wick, removed debris and moved it out of draughts, yes. Put it out and stop using it. For one of our candles, email us at info@hampshirecandles.com.
Enjoy a calm, clean-looking flame
So, why is my candle smoking? In most cases it comes down to a long wick, a draught or a candle that has been burning for too long. Trim the wick to 5mm before every use, keep candles away from draughts, burn for no more than 4 hours at a time and stop when about 1cm of wax is left, and you should enjoy a steady, smoke-free flame.
Our candles are hand-poured at our workshop at Eastover Farm, Abbots Ann, near Andover, using 100% soy wax and premium fragrance oils, with more than 200 fragrances across the wider range.