Once you light your candle let it burn until the top layer of wax has melted all the way across. This might take several hours so make sure you have the time to burn, so to speak. If you are not achieving a full melt on your burns you will be programing the wax to create a 'tunneling effect. If the wax is not allowed to melt from edge to edge of the vessel, it will create a “tunnel” a wax wall around the wick eventually become impossible to light. Once a candle has tunneled, it will continue to burn that way for the life of the candle, eliminating the full burn time of your candle.
4 Hour Burn times are optimal