It goes without saying, even to the candle novice, that wax is an integral part of the candle-burning process. However, have you ever wondered what actually happens when candles run out of wax? Perhaps it has been one of those 3 am questions that your brain simply had to know. We take a look at this topic now and explore if they carry on burning without wax being present.
Candles should not be left to burn without adequate wax or wick left. To do so can be a fire risk as the heat will become too much for the surface the candle is on and the container itself. Stop using your candle when you are down to ½ inch of wick left and reuse the wax for something else.
What happens if you let a Candle burn all the way down?
Before we answer this, did you know that there is a specific way to burn your candle the first time you use it? This is because you want your wax to burn evenly so that you aren’t left with a load of wasted wax at the end. The first burn should continue until the entire layer of wax has liquified.
What happens, however, once a candle has burnt all the wax? We all love to get every last possible minute out of our purchased candles. It is important though, to stop it from burning at a certain point. If you let your candle burn all the way, the heat has the potential to become too much for the container. This can cause the candle holder to become damaged or smashed, risking a fire.
We are all aware of candle safety – not leaving a candle burning unattended, not leaving it close to combustible sources… But what happens if we allow a candle to burn once the wax has melted? Does it even continue to burn? The short answer is that the candle becomes extremely dangerous once the flame has no wax to burn.
Instead, the heat concentrates on other sources around it such as the container itself. The container may not be able to handle such intense heat and could crack or smash. You should always aim to blow your candle out once you are left with just ½ inch of the wick.
Where does the wax go when you burn a Candle?
Have you ever watched your candle and been fascinated by the melting process? Ever wondered where that liquified wax goes and why it doesn’t spill over your table? Time to turn to science for a few minutes.
When you burn a candle, you will notice when you blow it out that the wax has reduced in size. Quite simply, there is now less wax than there was before. This happens every time you light the candle until the wax has all gone. Wax is made up of hydrogen and carbon so when it burns, it mixes with the oxygen in the air. This, in turn, produces carbon dioxide and water vapor.
You might feel a little uncomfortable to learn that carbon dioxide and water are being breathed in by yourself. However, in such low amounts, this is perfectly fine and normal. The wick has the important job of keeping the fire going. The wick allows the carbon and hydrogen to make their way into the flame. The particles are dispersed through the heat and what is left continues to melt the remaining wax.
How do you know when a Candle runs out?
We know the recommended advice is to leave ½ inch of the wick at the end of the candle’s life. However, without closely watching those final burn times (which takes the relaxation out of it, surely), how do we know the candle is running out?
You will often be left with a little bit of wax which can be frustrating at the time. You may feel like you want to get every cent’s use out of the candle. However, many candles are made with this spare amount of wax. Burning this down can burn the surface underneath or damage the holder. Candles make up a huge percentage of fires in homes so it is important to heed this advice.
You should just keep an eye on your wick before you go to burn it. Check the size of it (after trimming) and assess if there is still enough length to safely burn it. Don’t fret if you still have unused wax, you can always melt it down and recycle it in another candle. For more information on recycling your candles, you can read our existing article; Where To Recycle Tea Lights.
You might also notice towards the end of the candle’s life, the flame becomes sooty and smoky. This happens when you get the mushroom effect on the tip of the wick. The wick may also topple to the side, causing a disruption to the flame.
Why should you never burn a Candle for more than 4 hours?
There is a golden rule around burning time, if you know, you know. Burning a candle for too long can harm the wick, cause smoke, and is no good for anyone. This golden rule tells you never to burn a candle for longer than 4 hours at a time. Let’s now explore why this is so.
When you burn a candle for a prolonged period, you can end up with too much carbon on the wick. Too much is produced than can be vaporized into the air, so it sits on the wick. This, in turn, causes smoke to be produced and there is a build-up of soot. Once you blow the candle out, you will see the wick has a widening tip, known as mushrooming.
Also, burning it for too long can drastically reduce the candle’s lifespan. You end up with a tunnel effect through the wax as it burns unevenly. This will leave you with a lot of unused wax and minimal fragrance. For a perfect experience, never burn a candle for less than 1 hour and more than 4 hours.
What to do with leftover Candle Wax
You might be reading this too late and therefore, have some leftover wax that you don’t want to simply throw away. Can it be saved? Is there anything you can do to extend its life? We have some suggestions for you, don’t worry!
- The wax left will be fairly minimal so it will be the perfect amount for making a tea light out of.
- Why not save it for sealing an important note such as a wedding acceptance? There is more on this topic in our article; Do Wax Seals Hold Up In The Mail?
- Make your own wax melts from all your unused candle wax. They are simple to do and can be very rewarding too.
- You could make some wax fire starters.
- Got a squeaky door hinge and no WD40? Hello, candle wax.
- Making an ornament from your candle wax is another great way of recycling it.
To summarize our thoughts, your candle should never get to the point of running out of wax. So, if you have found out what happens, such as a broken candle holder, then you have burnt it too far down. Candles should be discarded after you are left with just ½ inch of wick on small ones and 2 inches on large, pillar candles. This is because the safety net of that buffer of leftover candle wax becomes less and less. This increases the likelihood of the heat impacting the container or the surface instead.
As well as caring for your wick throughout the candle’s life, you also need to keep an eye on the length. This should be easy to do if you trim your wick (as you should) after each use. When you notice it is very short, don’t be tempted to burn it one last time. Instead, think of all the exciting things you can do to reuse that wax rather than throwing it in the trash.