We all want our candles to look stunning, perform well, and burn safely -
I have heard many stories of grief in my years as a professional candle maker and trainer, and I cannot overestimate how important it is to conduct test burning on your candles before selling them. When things go wrong, its a fact they can go VERY wrong!
I used to share this story with my candle students to emphasise my point.
A few years ago, two work colleagues decided they would learn to make candles. One booked into our basic candle making class; her colleague decided she would teach herself. The colleague was getting married in two months and she decided it would be nice to personalise her wedding by making her jar candles for the reception tables, and as a wedding favour for guests. After a few practice sessions, she made her candles. She did a short burn and noted a full melt pool, so was pleased with her results.
On the night of her wedding, four hours into the reception, one of the larger jar candles shattered throwing shards of glass outwards, and a wedding guest was hurt. Within a few minutes, two other jars also broke. The venue staff immediately removed all candles. The bride was mortified and made the decision not to give out the wedding favour candles for guests, in case they too shattered.
After chatting to me several weeks later about how she made the candles, it became evident to me she had used too large a size candle wick for the diameter of the jars - so when they were lit, the wax prematurely melted, overheated and when the jar could not withstand the heat it shattered.
How to conduct a test burn
Trim the candlewick to 2.5cm. If testing multiple candles, make sure each one is clearly labelled. Place candles on a clean, flat, heat resistant surface 100mm apart. This area should be visible from your workspace, as the candles must not be left unattended while lit
Take note of the diameter of the container.
NOTE: on average a candle will burn 2.5cm per hour. Based on this diameter establish a time limit (for example a 5.0cm container should obtain a full melt pool in 2 hours, a 7.5cm container in 3 hours etc.)
Light the candle(s) and record the time. It is critical to keep an eye on the candles while they are burning when testing new candlewicks. This way, you see what your customers will see!
If necessary, make adjustments to the wicking and retest the candle before it is given away or sold.
Most candle makers want a container candle to achieve a full melt pool (burn all the way out to the edges of the candle) but if you are making a pillar candle you'll probably want to end the test burn when the candle is approximately 25mm from the outer edge of the candle to avoid the possibility of spillage.
Always remember, you can be vicariously liable if you do not provide proper instruction on the lighting of a candle, so always add a fire warning label to your candles before passing them on to family, friends or the general public.