Tunneling usually happens if the first burn wasn’t long enough. Coconut wax has a memory. The key is ensuring the first time you light your candle, you let it burn until the entire top layer of wax has melted into a full liquid pool, reaching the edges of the jar. This might take 2-4 hours. If it has already started tunneling, you can gently use a spoon to scrape the edges down to level the wax before the next burn.