The color of the smoke coming from the kiln will give some indication of the temperature:

  • White = steam (too cool, add fuel more slowly)

  • Yellow = methane (a very damaging greenhouse gas, fire is too cool and overwhelmed with too much fuel)

  • Blue = some volatile gases are not being burned (blue smoke is hard to avoid completely, but indicates that the temperature is still on the low side)

  • Clear, nothing but heat waves = GOOD (this is what we are after; a hot, clean burn)

The ideal temperature to burn at is between 850 to 1,050 degrees F, or 450 to 550 C. Note that the smaller the kiln and the wetter the fuel, the harder it is to maintain the higher temperatures.

From Lehmann, 2007Frontiers in Ecology and the Environment

From Lehmann, 2007Frontiers in Ecology and the Environment