Updated: Apr 14, 2022
What is candle tunnelling?
Along your candle making journey it's highly likely you've encountered a situation when your candle hasn't been able to burn from edge-to-edge, forming a circular 'tunnel' around the wick and down through the core of the candle. This extremely common phenomenon is known as 'tunnelling'. No candle is immune from potentially tunnelling whether you're burning a $936 Fornasetti Profumi or a cheap and cheerful K-Mart lemongrass & ginger. Whilst visually unpleasant, and leading to wasted, unburnt wax, candle tunnelling is completely normal and, if you treat your candle correctly, avoidable.
Common causes of candle tunnelling? Some of the most common causes of candle tunnelling are highlighted below. Having a good understanding of what causes your candles to tunnel, will help you prevent it in future.
Irregular burning practices: Candles should always burn for long enough so that the wax pool has enough time to reach the edges of the candle vessel. Extinguishing a candle too early may lead to the formation of a tunnel.
Incorrect wick size: A very common cause of tunnelling is the usage of a wick too small for the volume of wax or the width of your vessel. A wick which is too small may, despite its best efforts, not have enough power to burn the wax from edge to edge. (Hint: check out our wick blog to help you choose the right wick!)
How to fix a tunnelling candle There are a number of ways to fix a candle which has tunnelled, including using a heat gun to blast the edges of unmelted wax, however, our favourite way is the tin foil method. Essentially, you can use tin-foil to create a dome around the top of your container candle, reflecting the heat back onto the unburnt wax, causing it to liquefy and join the already melting wax pool.
How can you prevent Candle Tunnelling?
We've gone through what candle tunnelling is, what the causes are and how to fix a tunnelling candle, however, as they say, prevention is better than a cure. To prevent candle tunnelling when making candles always follow these steps:
Ensure you're using the correct wick for your jar size (always test!)
Use an appropriate wax type for the type of candle you're making
Don't overload your candle with thick, viscous fragrance oil (this can make your wax harder to burn through)
When on-selling your candles, always mention to your customer to burn the candle from edge-to-edge. Perhaps you can add a label or a little note with burning instructions.
Download and use the free testing sheet put together by All Seasons Wax Company to fine-tune your process and research how to get the best result.