Making Charcoal

Making charcoal is not difficult and for little effort you can make lots of this fuel from fallen timber and this can be green or seasoned and all you need is a container to make it in and somewhere to store your finished product as charcoal is useful as a stand alone fuel for straight burning or a fuel which can be fan fed for sufficient heat to melt steel.

Charcoal has one great advantage in that during its production most of the wood gas and moisture are burned off and this makes it a cleaner burning fuel which you can use for anything from a barbeque to a blacksmiths forge and reach extremely high temperatures.

To make this useful fuel you need several things and I prefer the 45 gallon drum method as this makes large enough quantities for me and other villagers and it can be used in our wood burners or on the barbeque to simply provide heat or just to cook on and a tightly fitting lid to limit the amount of oxygen to the drum or clamp is all that is necessary to make large quantities.
Charcoal is basically made by burning wood in insufficient oxygen and insufficient oxygen means it burns without igniting it and burning it all away so there is nothing useful left and by limiting the oxygen and preventing flames you actually part burn and part cook the wood by removing the wood gas and moisture.

Method One

This is the open burning method and takes several hours and generally this is 5-7 hours for this quantity of material and you need a huge quantity of differing size material and this ranges from twigs right up to timber as thick as your wrist and this can be collected during the winter or summer.
To begin you make your clamp and the clamp is the container you cook in and for a 45 gallon drum you put a series of holes in at the side close to the bottom; I mark out 1” from the bottom and every 4” around the drum diameter and drill a ½” or 12/13mmm hole in it to allow air to enter and remember you need insufficient air. You need a tight fitting lid to fit on your drum and the clamp ring type are ideal as long as they don’t have rubber or plastic seals inside them, or a sufficiently thick plate large enough to cover your drum will suffice and its object is to stop large quantities of air from entering your drum from above and letting the wood burst into flames and burn away.

I stand my drum on soil and get a bucket full of the smallest twigs and throw then into the middle of my drum on the bottom and light them and as they are the only fuel they are the only things which burn, once alight I throw on a couple more buckets of twigs and allow them to catch and burn and now we need to understand the process.
When you burn something in a drum it burns from the bottom up and if you add too much material it burns from the top down as only the top fuel layer receives plenty of air and this is why fires smoulder in a drum and suddenly burst into flames and this is because they suddenly receive a surplus of oxygen. We use this knowledge to control our burning and regulate it by watching our previous layers and watching until they turn black and then get a silvery tinge and then load our next layer.

This layer is wood about as thick as your finger and again you put it on by the bucket load and you watch this burn and turn black with a silvery tinge and you add your next layer and this is slightly thicker wood about 1” or 25mm thick and you loose lay this by not putting it in and not laid in the same direction. You put some laid in one direction and more laid in another direction so you fill your drum with this wood and by allowing each layer to burn through you are burning off the wood gas and moisture from the wood and allowing it to escape.

You continue with your successive layers being 1.5” or 40mm, 2” or 50mm and 3” 75mm thick and at each loading you are raising the burning material height in your drum and burning it through and when your drum is full you put your lid on and leave it and every couple of hours you remove your lid and let the timber ignite and replace your lid and once everything is black with a silvery tinge you have finished. Leave your drum overnight to extinguish and cool down, sometimes it may need two days and once you have your charcoal it’s simply a matter of breaking it up into pieces and storing it.

What wood should I use? For this method you can use softwoods, hardwoods, or a mixture of both but you really need to watch your fire to prevent the softwoods from burning away and not burning the hardwood sufficiently to turn it to charcoal.

What is the maximum thickness timber should I use? In reality 2.5 – 3” is the thickest you should use.

Method Two

This method is the same method commercial producers and woodsmen making their own charcoal use and we are merely using a smaller version of it and producing our version of it and producing charcoal in large quantities for us but these are small quantities for commercial producers. This can take up to 20 hours to produce a good charcoal but it is efficient and reliable and its efficiency in producing charcoal is around 90%

We make our clamp by turning our drum over and marking a circle of about 8” (200mm) diameter in the middle and drilling a series of 8mm holes inside this circle and we punch a nail through the rest of the drum bottom to make many small holes to draw air through. We turn our drum over and stand it on four equally spaced bricks to allow air to flow under the drum and feed out charcoal burner.

This method allows timber of any diameter to be turned into charcoal and for larger diameter timber we simply split it in half for slow burns or into quarters for faster burns and larger diameter timber is split many times until it is small enough to be cooked in the clamp and we begin as follows.

We cut out timber into lengths slightly shorter than our clamp internal height and we take an 8” (200mm) diameter log and stand this in the middle of or empty clamp/drum and we split our cut lengths into pieces and begin stacking them around out 8” diameter log and work outwards until our clamp is full. We carefully remove our 8” diameter log and we should be left an 8” diameter hole in the centre of our clamp right above our larger 8mm diameter holes and this is where our fire goes and is allowed to burn in insufficient oxygen and turn all our timber into charcoal and we have two choices of fire source now.

Method 1 is to make a fire in a steel bucket or drum and begin with small twigs and work up to larger diameter timber and let it burn down to nearly a smoulder and take the smouldering timber and pour it into this hole in the centre of the clamp and the 8mm diameter holes should provide enough air to allow it to flare up. These glowing embers are encouraged to burn by topping up with more smaller twigs and allowing them to burn and top up the hole with progressively larger timber until you have a good fire in the hole.


Method 2 is to light a fire in the hole directly and build the fire in there and I do this by screwing up paper and putting it into the bottom of the hole and covering it in wood shavings and twigs and I get a long stick and dip one end in petrol or diesel and lighting it and placing it directly under the drum and light the paper through the holes drilled into the bottom. This allows the paper to ignite and this ignites the shavings and the twigs and you simply add more and thicker sticks until it is roaring.

With fires roaring in the centre hole it is time to put on the lid and what I do is to put the lid on and put a piece of 6mm thick steel plate under one side to lift it slightly off the drum and as it burns it allows the wood gas and moisture to escape and produce quality charcoal. During this initial phase of burning I find it appropriate to evacuate many of these wood gases and steam as this dries out the wood quicker; particularly if it is green or unseasoned wood, and it moves to the burning phase and then the cooking phase and gives a more consistent result. Always ensure you don’t remove all the steam and wood gases as they actually act to dampen the fire down and stop it flaring up and burning the wood instead of cooking it and it is useful to learn and adapt to your chosen methods and watch how your chosen woods burn and cook and there is no substitute for experience.

This is now where experience comes into play and you need to learn how long to leave your clamp before removing the lid, leave it for too short a period and you won’t build up enough wood gas and steam to slow combustion down to cooking and leave it too long and the fire simply goes out and you end up with a pile of part burned timber.
You really need to work out your timings and remove your lid by sliding it over so part of the clamp is exposed and the sudden inrush of air will cause the fire to ignite flames and burn viciously and you slide your clamp lid in another direction to get a surplus of air to another part of your clamp and fire this up and repeat this so all of your clamp is alight. If you have a 45 gallon drum and a fairly light lid you can either weld on a couple of handles or use a pair of self locking pliers such as Mole Grips and grab your lid and totally remove it and your clamp will flare up and once burning viciously you simply replace your lid and carry on with your charcoal making.

Once completed you simply put your clamp out by leaving your lid on and blocking your bottom air holes with wet clay or moist soil and extinguishing all the air stops the combustion process and your clamp goes out and you leave it overnight to cool. Remove your charcoal and discard any burned wood which is no good and keep your cooked wood and break it up into lumps and store until needed.

So much useful knowledge, thank you. It will have to wait until winter but can start collecting wood now, while its dry.

More superb advice, thank you Assassin.