Fuel
Fuel
Fuel Myths
People often make erroneous claims for the properties of certain woods for fuel. Most of these are untrue.
One of these myths is the idea that certain woods produce a sweeter smelling smoke. Bear in mind that 100% of all smoke and combustion products are supposed to go straight up the flue and away. If you can smell smoke, find out what the problem is and fix it AT ONCE. Never tolerate fume leakage. All fuel should be dry and stored sensibly.
Coal is basically divided into smokeless and house coal, with the latter producing more soot. Anthracite is a natural smokeless coal. Most smokeless fuels are formed by taking house coal and baking it in the absence of air, mimicking the natural processes that create anthracite.
Buying Firewood
The only thing that you need to consider when buying wood is its dry weight.
The heavier it is, the longer it will burn, and the better the embers will be. That's why hardwood logs like oak cost more than soft woods.
Woods that are very light due to the action of rot and fungus are almost worthless as they tend to burn very slowly and dully.
Never accept green or wet wood from a wood seller, as you will need to store it for a long time before it will be suitable.
How to Identify a Well Seasoned, Dry Log
When a log is cut up for fuel, the water starts to escape from between the fibres of the wood, and those fibres pull apart causing cracks that go from the centre of the log to the bark. These are called radial cracks. A seriously seasoned log develops a grey tinge, and two such logs banged together are said to almost 'ring like a bell'.
To detect green wood scratch your car keys over the bark. The tissue below the surface should be brown and dry right down to the wood. Any green tissue implies that the wood is green.
Green vs. Seasoned & How to Reduce the Risk of Tarring
Dry is, in my opinion more important than seasoned when choosing your wood. A green log is not hugely different to a wet, seasoned log, and neither should really be used. I have seen people burn what they shouldn't, and suffer no problems with obstructed flues. On the other hand, I have seen people burn wood that has been seasoned and dried for 8 years, and still tar their chimneys solid.
The worst offenders are those who burn a wood burner almost out, fill it with wood and then shut it down for the night. This turns the stove into a destructive distillation apparatus, which will sweat tars and creosotes into the flue.
The correct technique appears to be as follows:
1) Run the stove hot
2) After filling it for the night, burn it hot to drive off the volatiles, until about a quarter of the wood is gone
3) Shut it down for the night