Common Candle-Burning Problems: Why Is My Candle Tunneling?

We’ve all been there: You find an amazing candle in the perfect scent, and you’re so excited to get it home and start burning it. Then, by the time you’re lighting it for the third time, half the wax is hanging out in a ring around the rim where the flame can’t reach it. What a bummer! Not only does your candle last half as long this way, but you can also barely smell it at this point. So where did you go wrong? And what options do you have to remedy the situation?

All hope is not lost. Here’s why your candle is tunnelling and what you can do to save it—and prevent it the next time around.

You’re Not Burning It Long Enough

Soy wax, in particular, has something called burning memory. So when you burn it for the first time, that wax pool will create a boundary for future burnings, and the next wax pool is unlikely to cross it. That’s why it’s important to burn a container candle for long enough to completely liquify that top layer, especially the first time you light it. Neglecting to do so will lead to tunnelling. For that reason, it’s best to wait to light a candle for the first time until you know you’ll have at least a few hours to let it burn.

A Note for Teacup Candles

Please note, you should never burn a candle for more than 4 hours at a time. Since teacup candles don’t have a consistent diameter from top to bottom, the wick size is based on the average diameter of the container. This means 4 hours may not be long enough to liquify the top completely.

Have no fear! As the wax burns down in subsequent burnings, making the diameter of the candle smaller, the wick will be more effective, and the built-up wax will start to melt from the sides. 

You’re Not Trimming Your Wick

A lot of people aren’t aware that they’re supposed to trim a candle’s wick, even before the first time they light it. Most candle manufacturers recommend trimming your wick to between one-fourth and one-eighth inch each time you light a candle, including the first time. This simple trick can drastically reduce wick mushrooming and uneven burning—which, in turn, prevents tunnelling.

Your Wick Is Not Centered Correctly

This one isn’t in your control, but you still have to deal with it. The candlemaker could have misaligned the wick for any number of reasons. It’s possible the container shape was irregular, the wick sticker slipped, or maybe they were just moving too fast. Any way it goes, an uncentered wick can lead to tunnelling on one side of the candle.

How To Fix It

So what do you do, now that your candle has an inch of tunnelling on it?

There’s a simple trick to get the built-up wax off the sides of your candle without damaging the rest of it, and all it takes is a trip to the kitchen. Grab yourself a length of aluminum foil long enough to wrap around your candle with about half an inch of foil hanging over the top of the rim.

Another important step here is to not trim your wick (just this once) quite so much before lighting it. You’ll understand in a minute.

The foil around the outside of the candle will more evenly distribute the heat from the candle flame through the sides of the container. As a result, that buildup of wax will melt down the sides and into the existing wax pool, raising it slightly. That’s why you want a slightly longer wick during this burn—if you trimmed it like you usually do, this extra wax could drown the flame.

And that’s it! Simple, right? Now that you know why your candle was tunneling, you’ll know how to prevent the issue next time. It’s not always in your control, but you can rest easy now that you also know how to fix any tunneling you encounter in the future.