(Be sure and check this entire blog for lots of other ideas and tips for candle burning problems too!)
First, and most usually, the wick is too long. Try trimming the wick a little at a time with an old finger nail trimmer or small scissors. Light the candle between each trimming until the candle no longer smokes.
Second, the candle may have a property that prevents an even flow of wax into the wick. This can be caused by problems with the scented oils added to the candle during manufacturing, or an abundance of non-emulsifiable dye (coloring that can not blend with the wax efficiently). If this is the problem, it may be impossible for the candle to ever burn properly. If you arrive at this as your conclusion, it should be your last. You may attempt by pouring off some of the wax into a piece of aluminum foil. (Discard the foil properly, and responsibly.) Remember, never pour wax into any of your drains, this will cause costly repair! Attempt to light the candle. The problem may have been isolated to a particular portion of the candle. Good luck!
Question: My candle makes a crackling sound as it burns! Why?
If you keep your candles in the freezer, click here.
If not, this can be caused by several factors.
First, usually this is caused by water, or other moisture being present while the candle is burning. This could have occurred while the candle was being made or between a burning session. Try to keep candles in a cool and dry place to avoid this.
Second, crackling can also be caused by other improprieties in the wax. It is recommended that a crackling candle be extinguished immediately and discarded or returned to the place of purchase. It simply isn't worth the risk.