My candle is tunneling, why is this happening?Updated 8 hours ago

Tunnelling happens when the candle isn't burnt long enough for the melt pool to reach the edge of the glass. This usually takes 1 to 3 hours, so burn for 1 to 3 hours at a time.

Normally, trim the wick to 5mm before each burn. If your candle has already started to tunnel, skip trimming for the next burn only. A slightly longer wick gives a bigger flame, which helps the melt pool reach the edge. Once the wax melts edge to edge, go back to trimming to 5mm before every burn.

• Avoid drafts: keep it away from open windows, fans and vents, on a flat surface
• Rescue tip: wrap a collar of foil around the rim, folded slightly over the top, and burn for 15 to 30 minutes under supervision until the surface levels

more help: how to burn a candle properly