Making charcoal

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1. Preparing the Kiln

Charcoal is made by burning wood in the absence of oxygen, and at Warburg we do this in a large metal kiln. The first job is to ensure there is an airtight seal around the kiln base.
A small pile of charcoal is then placed in the bottom of the kiln. This is known as the ‘charge’ and will start the wood burning once the kiln has been stacked. Large diameter logs are then laid round the base – these are called ‘stringers’ and allow air to circulate to get the fire going once the kiln is lit.

2. Stacking

The kiln is now ready to be stacked with suitable wood. At Warburg we mainly use hazel, ash, sycamore and lime as this is what becomes available through our woodland management activities. We normally use wood which is between 2 and 4 inches in diameter.

 

 

 

 

 

 

During the stacking process it is necessary to keep small gap in the centre of the wood using a spacer. The resulting hole acts like a chimney inside the kiln and also helps to get the fire started.
When the kiln has been fully stacked, the spacer can be removed and the burning can commence.  

3. Starting the Fire

A separate fire is established to produce a large amount of hot embers to light the kiln.
The hot embers can then be tipped into the ‘chimney’ hole in the kiln, down onto the charge at the bottom. It is now time to put the lid on.

4. Putting the Lid on!

The lid is lifted onto the kiln, but wedged up with 4 pieces of wood to create an air gap. This means there is enough oxygen in the kiln for the fire to take hold.

 

 

 

 

 

After about an hour, the fire will be well established. The wedges are removed and the lid sealed down. Chimneys are also put into position to allow the steam and smoke to escape. The air supply is regulated by adjusting small vents at the base.

5. Cooling Off

After 16-24 hours (and a bit of luck), the charcoal should be ready! After a cooling off period of at least 48 hours it is put into bags ready to be sold to local residents and visitors to the reserve.