The oldest cooking fuel is firewood in the form of logs and branches from trees. Firewood can be categorised into hardwood and softwood: in comparison to hardwoods, softwoods burn more quickly and produce less heat owing to a lower energy (carbon) content per volume.

However, energy content per weight is similar for all hardwood and softwood; the moisture content of a firewood primarily determines its energy content. The drier the firewood, the less energy is needed to evaporate the water, thus the more energy is available for heating or cooking purposes.

Firewood cannot ‘burn’ directly. Initially it should be transformed into woodgas (pyrolysis), which can then be combusted when blended with a specific amount of oxygen and ignited. A temperature of over 300° C is needed to start the pyrolysis process and create combustible ‘wood-gas’.

In most cases, this ‘external’ heat is initially provided by a lighting material, such as kerosene or a match. Once the temperature starts to increase, the following processes occur:

As the biomass warms up and approaches 100° C, excess moisture contained in the biomass changes from liquid into water vapour. Excess moisture evaporates into the atmosphere and leaves a solid dry biomass behind. At temperatures beyond 300° C, biomass starts to pyrolyse. Increased temperatures eventually cause a complete conversion of the biomass into volatile vapours and a solid residue called char.

The vapours contain different carbon compounds with fuel value, referred to as ‘wood-gas’. Since the solid by-product of this process is char, mostly composed of pure carbon, the process is also termed ‘carbonisation’.

Drying and pyrolysis are both endothermic processes, implying that they burn heat and do not create any useful surplus of heat. The speed of the process is determined by the amount of available heat input and the amount of heat required to first dry out the fuel before the temperature of the biomass can attain a level at which pyrolysis can start: using air-dried fuel (moisture content of 10% – 20%) is recommended in order to shorten the drying time and minimise the required heat input.

The efficient burning of firewood is determined by the availability of oxygen and the temperature. Regardless of whether you burn wood in a fireplace, stove or furnace, good quality firewood is the key to efficiency, convenience and safety.

Wet wood and pieces that are not the right size and shape for your wood burner can be frustrating, burn inefficiently and deposit creosote that can fuel a risky chimney fire. Good planning, seasoning and storage of the firewood supply are important to successful wood burning.

Firewood for Sale in Sydney includes dry crackling firewood of different types: Red Gum firewood, Iron bark firewood, Mixed eco-friendly firewood, Box firewood, seasoned hardwood, hardwood logs etc. The length of the pieces must be appropriate for your stove, furnace or fireplace. Shorter pieces are easier to handle and preferable to pieces that are too long for the appliance. Choose top quality firewood in Sydney to ensure clean and efficient burn.