There are two main reasons for this. Like the mushrooming of candle wicks, smoking occurs when there is an excess amount of wax fuel to be burnt – this can be caused by an oversized wick providing more wax to the flame than can be burned or can also be due to too much fragrance. To solve this, we would recommend carrying out a test by first reducing the wick size and if the same problem persists, to try reducing the fragrance level.