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out" the fire, and therefore making it burn very poorly, which tends to
produce a lot of creosote and pollution.
Emissions
As the heat of the fire intensifies, waste-gases (smoke) are released from the
wood.
Unburned smoke is emitted into the air either as pollution, or condensed in
the chimney causing creosote build-up. It takes time for the air in your
chimney to heat up. When it is still cold you get an effect similar to the
condensation of hot breath on a colder window or mirror. So when the by-
products of combustion (smoke in the form of gases) exit the cooker, and
flow up into the relatively cooler chimney, condensation occurs.
The resulting residue that sticks to the inner walls of the chimney is called
creosote. Creosote is formed by unburned, flammable particulates present
in the smoke. It is black or brown in appearance. It can be crusty and flaky,
tar-like, drippy and sticky or shiny and hardened. Quite often, all forms will
occur in one chimney system.
If the wood you are using is water logged, or green, the fire will tend to
smoulder and not warm the chimney sufficiently. Wet wood causes the
whole system to be cool, and inefficient. In contrast: dry wood means a hot
fire, which results in a hot flue, and a hot flue means much less creosote
clogging up your chimney.
The cooker’s firebox is designed to operate at very high temperatures to
burn the gases and particles released from the wood, which means less air-
pollution.