This picture shows a RTS1000 single charge (barrel)  charcoal retort. Designed by Nick Harris at Four Seasons Fuel Ltd.

This charcoal retort produces about 700kg of quality charcoal during a 5 day burn or about 150 kg for a one day burn.

The charcoal retort is very ecomonical with fuel as once the fire box is lit no more fuel is required because it utlises the gases produced by the wood.

We can build a charcoal retort of any size and options to fit your budget and production requirements (From small single to large double with heat exchangers).

The Four Seasons charcoal retort boasts significant advantages over the more traditional ring style charcoal kilns offering:
- Improved production efficiency using less material to produce more charcoal (It produces a ratio of 1:4 instead of 1:7 of a kiln ring)
- Self fueling. Once started the retort reheats itself using the wood's natural gases.
- Improved productivity. Approx burn time of 8 to 10 hours (Significantly less than ring kiln).
- Greater range of burning control producing a higher quality charcoal.
- Better for the environment producing more 'friendly' emissions than a kiln.

Each retort is CE Marked and has been subjected to stringent quality control procedures in line with ISO 9001:2008 approved status.

We can deliver and commission retorts and kilns worldwide.

See a video of the RTS (1000) Retort

 

Introduction
This single retort charcoal manufacturer will normally produce 150kgs of high quality BBQ charcoal in 6 hours.

Lighting of the firebox can we achieved using any wood (5 or 6 wooden pallets works well)

Within 2 hours of lighting the temperature achieves 480 degrees C. Then no more fuel is required in the charge drum as it then uses the gases generated by the wood being charcoaled. The  temperature  then keeps a steady 500 to 525 degrees centigrade for 4 hours.

After that, the gases start to relax and the retort is left to cool.

Loading
Loading (charging) time for the retorts is approximately 45 mins. We stack ours by first stacking the front of the kiln, then throwing the wood to the back placing small at the bottom followed by medium at half way then large wood at the top.



Remember to keep the drains clear from the wood to avoid build up of water from the wood. (Such a build up will add to your burning time)

When all charges are full close the doors and making sure the top door vents are sealed with sand. Remember the charge must be air tight when the gases come in. When starting leave the drain hole cover off. When you start a burn you will see water and gases come though the bottom drain hole. Wait until the gases are dense then screw the drain hole cap on. Keep feeding the firebox, until the gases hit 300 to 38O degrees C (depending on the wood type you are burning).

The Cooking Time
Cooking times of as little as 8 to 10 hours can be achieved by preburning. (Cooking times without preburning takes about 6 hours longer)

Reburning
Reburning is very simple. After loading just light as before, keeping it going until the wood menthol starts to come though. Then leave it until the next day. You could put charcoal fines in the firebox, this will keep the temperature by slow burning over night. In the morning just rake the firebox to reignite, then feed as normal.
Once the gases are reducing this means that the cooking is over this will take time to learn.

Once the gases reduce you can either:-
- take the door vents caps off and wait till the temperatures drops to 350 degrees C and take the vent at the rear out. Leave to cool overnight and unload the next day. (Remember to replace the door vent caps, sand and seal to prevent air entering the charge)
- or you can just take the rear vent out and leave it.

NOTE: When you open the door and it feels too hot to unload close the doors making it air tight leave to cool longer.

When you open the doors and you see red embers this means that the doors were not airtight or the top vents where not sealed after venting off. Poor water over the red-hot coals, wait until water has exited, close the doors and wait to cool. The water will evaporate and dry the charcoal.

Cooling Time
On your first bum cooling time will take around 16 hours. After each burn your time should reduce and start to level out. (As residual temperature of the metal rises and the sand base dries out).


Smoke
If you work in a controlled area smoke can be trouble. The amount of smoke produced by wood in the firebox varies according to the wood type used. Treated timber such as pellets and tanning woods will smoke but if you use untreated soft wood there will be less smoke. On average the reduction of pollution with a retort is 75% less smoke than round steel kilns.
Once the gases come in around 300 to 380 degrees C or less there will be less and less smoke. Using a retort is a real advantage for reduction of air-pollution.

Venting Control
The retorts can be easily controlled by venting control. There are vents at the rear these are to control the burn which on each charge. For example, if the left change is burning faster than the right you would open the right vent 2 or 3 inches and close the left 2 or 3 inches. This will draw the heat to the right charge.

Venting Off
The safe temperature in one of the charges should be 550 degress C.  If this is exceeded the temparature can be reduced rapidly using the vents located on the doors. To vent off lift off the top and light the gases. This will reduce the temperature. Try to maintain the temperature at around 500 to 525 degrees C for as long as possible till the gases in the Firebox is not as strong as they were.

Finishing Off
Once the gases are reducing this means that the cooking is over. (This will take time to learn!)
When the gases have reduced you can either:-

- When the temperatures are around 40 to 45 degrees C it is safe to open the doors. Once open you will see how much the wood has reduced. If you see a few brown ends (wood that has not been cooked long enough) you will know that next time you need to keep the temperatures more constant and which wood to put in for quicker burning. (Oak & hornbeam will take longer than ash or beech. Birch will be the quickest wood to burn).

or

- Take the door vents caps off. Light the door vents each side the retort and wait until temperatures drop to 354 degrees C (remembering to sand and seal the door vents).  Then remove the rear chimney vents and leave to cool quicker. Next day unload.

or

- Take the rear vent out and leave it. Cooling time will be long

Happy burning!