The Charcoal Burners Manual

Charcoal Burning -The Process and description of Tasks involved for the successful completion of a Charcoal Burn

By R.V. Ridley
Summer 1999

Emptying the Kiln

  1. Emptying of the kilns should be done as early in the day as possible.
    Reason: It sets the pace for the rest of the days tasks.
    In warm/sunny weather, the protective suits make the work hotter/harder; it is cooler & easier to empty the kilns early in the day.
  2. Remove seal round lid using the spade with its blade convex side upper most.
    Reason: This disperses the sand, off the kiln, more efficiently than if the blade were the 'correct' way up or concave upper most.
  3. Stand, facing the kiln. Ensure two chimneys are on the ground, directly behind you. The chimneys should be approx. 1 meter from the kiln base and approx. 1 meter apart, running away from the kiln.
    Reasons: The distance from the kiln base allows sufficient space to clear out the 'ports' when emptying and allows free movement round the Kiln.
    When the lid is slid off the kiln, the metal chimneys allow 1 person to remove the lid, by sliding it along the chimneys and keeping the lid off the ground therefore not digging in. This method allows the lid to be replaced onto the kiln more easily, when filled, again by 1 person.
  4. The area between the chimneys on the ground, provides a safe place for the 'wood slices' (used to control airflow into the ports during a 'burn'), to be stored during emptying & filling operations. This is also were the 4 short straight 'chocks' (see '9a') used to suspend the lid during 'lighting', should also be placed when not in use.
    Reasons: This avoids the above items being damaged or placed in the kiln during the 'filling' operations. It ensuring that the items are:
    • easily available at the time when they are needed
    • that operators know where to find them and not wasting time looking around for them or them being 'lost'.
  5. Lifting the Lid.
    1. Standing with your back to the two chimneys on the ground (as described In '3'), place the corner of the spade blade, between lid and kiln rim, press down raising lid. Force the corner of the spade (concave/face side up) between lid & kiln and with further pressure, insert half of the spade blade into the gap you have created. Push down on the handle fully. This will prise the lid form the kiln. Pushing further down on the handle should cause the lid to move towards you. Work the lip of the lid over the kiln side, again toward you.
    2. Put down spade, take hold of lid and gently draw it towards you until Approx. two thirds of the lid is over the side of the kiln. Gently bend your knees and allow lid to rest on the chimneys. Moving round the side of the slanting lid, gradually slid lid on to the chimneys. Move the leading edge to the lid along the chimneys away from the kiln. Allow the weight of the lid to be taken by the kiln and chimneys as it slides downwards. Avoid struggling with the weight as this is likely to send the lid off the chimneys, on to the ground and make handling harder.
    3. Moving to the 'back' of the lid by the kiln, ease the lid off the kiln completely and gently move it over the chimneys, bending knees, slowly lower lid onto chimneys at ground level.
    4. Ensure that the lid is far enough down the chimneys away from the kiln to allow for unhindered access to ports during the 'clearing out' process.
  6. Emptying Kiln
    1. Place the square Aluminum shovel through one of the kilns rectangular side handles. The blade/face of the shovel is facing the kiln. Stand the round head shovel in one of the sand filled round ports. There should be sufficient space between the two 'T' handles of the shovels to suspend one of the large plastic bags. Fold the top of the bags over twice approx. 3" each time, to allow the fold to be placed over the handles, thus suspending the bag and holding it open. The bag should be on the inside of the kiln.
    2. Standing outside kiln, dig out the charcoal next to the bag to create a space in which to stand within the kiln. Dig down to the floor before attempting to stand in the kiln. Fill bag approx. 3/4qts full.
      Reason: Standing on the charcoal crushes it, thus creating a lot of smaller, unsaleable pieces. 3/4qts is approx. 25kg and is heavy enough still to be lifted by one person.
    3. Once a space has been created big enough to stand in, (so as not to crush the charcoal), climb into the kiln and start to fill the bags. Work from the edge of the kiln in one direction, anti clockwise if right handed, clockwise if left, filling the bags. Clear down to the floor & extract charcoal from the ports as you uncover them.
      Reason: Working round the edge of the kiln will lessen the damage caused to the seal at the base if the kiln. Digging TOWARD the side of the kiln wall will increase damage to the seal at the base. By working round the edge in one direction, any 'spilt' charcoal will fall toward the bag or direction of work thus leaving the increasing cleared area behind you - thus saves clearing an area twice. This method avoids you having to stand on therefore crush charcoal.
    4. Carry on emptying kiln, carefully watching out for Par-char and footings. Care should be taken to try and minimise the amount of dust that is placed in the bags, use the fork tongs to help screen this out.
      Reason: Screening at this stage is part of the Quality Control to ensure that only material suitable for Barbecues enters the bags.
    5. When the kiln is empty the floor of the kiln should be made flat and level. Check the seals round the base of the kiln in side & out and build back up with dust & sand as necessary.
      Reason: A broken seal can allow additional air to enter the burn thus sending it out of control. It would be possible to damage the kiln by melting, if the heat becomes to great.
  7. Cleaning Ports
    This process is made easier if the main clearing of tar is done at the 'close down' stage of the burn (i.e. when the tar/ports are hot). Thus the next instructions start during the 'close down' period of a burn.
    1. When the port has pinked or is about to be sealed, clear way all tar from around the vertical part of the port. Scrape tar off the out side, from where the chimney sits, not forgetting the section at the 'back' nearest kiln.
    2. Open rectangular port and remove tar deposited on the inside. Run the spade through the port, to the inside of the kiln ensuring all tar deposits are removed. This may take some effort on occasions but is ESSENTIAL.
    3. When port is completely clear, fill both round & rectangular ports with sand & soil, making airtight seal - no smoke should be seen to be escaping.
    4. Whilst emptying kiln, remove all sand from the round and rectangular ports. Run spade though ports to ensure they are completely clear. Do this from the inside as well as outside the kiln.
      Reasons: Clearing the ports whilst hot enables the tar to be removed easily. When cold the tar is extremely difficult to remove. A build up of tar & sand can;
      • cause the chimneys not to fit on the ports correctly.
      • reduce the airflow causing a poor/irregular burn.
      The ports are VERY easily & quickly cleared when cold, IF the above procedure is followed.
  8. Filling Kilns
    1. With the kilns completely empty, the floor leveled and flat, the ports totally cleared out, and the seal round the inside of the kiln intact, then the process of filling can commence.
    2. Select a suitable length lighting stick -approx. 5' to 6', and insert through an inlet port, on the lea side of the kiln. Ensure the end reaches the "dead center" of the kiln, whilst the other end protrudes from the rectangular port on the outside of the kiln. It is vital that this lighting stick remains free and movable at all times during the following filling process.
      Reason: Choosing the lea side for the lighting stick will make lighting the stick easier out of the wind. If the stick becomes trapped then it will not be possible to light the kiln by this method.
    3. Select and place in the kiln 8 'footings'. These will be similar sized pieces of wood. The diameters of which, should be no less than 3" nor greater than 5". Try and select all footings of a similar size i.e. all 5" diameter or all 3", rather than say; 4x3" & 4x5" etc.
      Reason: Too small a footing i.e. 2" - and there will be an insufficient air gap to allow air to flow through the kiln during the 'burn'. Too big a footing will create an unnecessarily large air gap, thus wasting the valuable burning space for more wood/charcoal.
    4. Place the first two 'footings' either side of the lighting stick on either side of the of the port it is protruding from. Lay the remaining 6 footings, in a spoke shape, between each of the remaining ports. One end of the spoke should be resting at the kiln base bedded into the kiln seal. The other end runs into the center of the kiln. Ensure that a few inches gap is left in the center of the 'spoke', for the lighting stick to remain free & rest in the middle of the kiln.
    5. Build a 'fire place' on the footings in the dead center of the kiln over the end of the lighting stick, using 'parchar'. The Fireplace should be approx. 12" square and approx. 12" or 3 or 4 layers high. The 'fireplace' center must be directly over the end of the lighting stick.
      Reason: This is where the 'burn' is started. The lighting stick MUST be under the fireplace so it catches immediately.
    6. Use 4 large diameter pieces of wood (approx. 6" to 8") and create a square around the fireplace 'holding' it in place. These pieces too, rest on the 'footings'.
    7. Starting with the 2 'footings' on either side of the lighting stick, lay a floor of logs & sticks in parallel - working from the fire place toward the kiln wall. The diameter of the wood used should decrease as you move away from the center but the length should increase, thus spanning the spokes in the form of a rough triangle.
    8. 'f ' should then be repeated with the opposite pair of spokes. So if 'f ' were 12 on a clock, this would be followed by 6 and the by 3 & 9. This creates a Maltase Cross effect.
    9. There will be gaps between the 4 principal sections, these should be covered with addition lengths of wood laid in one direction. The effect should be to have created a suspended floor on top of the 8 'footings' with only the 'footings' touching the ground, and with the floor in place, no ground visible.
    10. Once the floor is complete, commence filling the kiln. All wood should be laid in one direction which is usually directed by how the floor has turned out i.e. in the same direction as the wood used in ' h'.
    11. Place larger material inner most and thin material round the edges. Larger (4"+) diameter material, should be left out of the kiln until the kiln is over half full, and the care should be taken not to place large material around the edge of the kiln. If there is par-char left over, that can be place lower down the kiln, around the edges.
    12. The 'charge' (wood) should be packed in a tight a possible with gaps &
      holes filled as you go along, with shorter pieces of wood - you do not make charcoal from air gaps!
    13. The kiln is filled to the rim. Ensure that all wood at the rim edge, fits under the rim - enabling the lid to sit & seal. From the rim, wood can be built and angled to form a cone shape mirroring the lid shape itself.
    14. The lid can now be lifted onto the side of the kiln in a reverse of '5'. Pushing the lid over the wood charge and ensuring that it sits well on the rim. If the lid does not sit correctly & is raised at any place off the rim, then it needs to be lifted and the obstacle removed which is preventing the lid from sealing at the rim.
  9. Lighting the Kiln
    1. With the lid on, collect 4 straight & clean - 3'x3" pieces of wood, used to suspend the lid off the kiln - know here as 'chocks'.
    2. As in '5a', use the blade of the spade to raise the lid off the kiln sufficiently to insert one of the 'chocks'. Move a quarter of the way round the kiln and repeat. Repeat a 3rd & 4th time so that there is a 'chock' at 12', 3', 6' & 9' O'clock.
    3. Rest a chimney on the kiln, next to each of the 'chocks', placing the 'bottom' of the chimney upper most, so approx. 12" to 16" of the chimney is pointing above the rim of the kiln.
      Reason: This will allow the position of the 'chocks' to be identified even if covered by dense smoke. The 'bottom' of the chimney will heat up, when inverted and placed on a port, a warm plug of air will rise up the chimney drawing smoke out of the kiln and thus assisting in the start of the air flow & burn cycle.
    4. Mark exact position on the lighting stick where it lies in the port before removing it. Tie a rag to the end, immense in diesel etc. and ignite. Place lighting stick back into port and reposition in exact same place as prior too removal.
    5. The fireplace should now slowly catch light. Great amounts of smoke will be given off. After approx. 30 minutes, check the temperature of the kiln by spitting on the lid about half way to the top. If the spit sizzles, the operational temperature has been reached & the lid can be sealed.
  10. Placing the lid on lit kiln
    1. When required temperature is gained, commence filling in alternate rectangular ports - these will become the first outlets. Determine this by appointing the port with the lighting stick as an inlet, it follows that the ports on either side will thus be outlets.
    2. With the outlets filled, remove 3 of the chocks, and invert all of the chimneys.
    3. With all 4 chimneys on, remove the last chock, the resultant down pressure of the lid falling can help start the cycle of the burn by forcing air/gases out of the chimneys .
    4. Store the chocks in the save place as in point '4.',at this stage - so that they do not get misplaced.
    5. With the lid down, seal the rim with sand and stop any smoke escaping. Fill in the rectangular parts of the inlet ports so only 4 alternate round ports are acting as inlets.
    6. As necessary, set wooden discs on the ports & chimneys according to the weather conditions and dryness of the wood to control the burn process etc.
  11. The Burn
    1. The first 50 to 75 % of a 'burn' is the wood being dried out. This is represented by white 'fluffy' or steamy smoke and can take from 6 to 18 or 24 hours dependent of the moisture content of the wood.
    2. When the smoke darkens and goes thick & 'yellowish/brownish', the 'burn' has entered its latter stage, the moisture has been driven out and the chemicals inherent in the wood are now being given off. The burn needs to be observed closely from now on. Thick black tar deposits at the base of the chimneys further indicate this stage of the 'burn'.
    3. Chimney changes, i.e. moving each chimney round one, so that an inlet becomes an out let and visa versa, helps the 'burn' along and produces a more even burn. Timings of these chimney changes comes with experience. Try 3hr, 4hr and longer times between changes and see what effect this has on you burns/output/work patterns etc.
    4. Such a chimney changes especially towards the end of the 'burn cycle', often produce a change in the smokes characteristics. The burn therefore needs to be observed for several minutes after a chimney change in order to correctly determine at what stage the 'burn' is actually at. In so doing, decisions can be made about what to do next, how long to leave the burn, or that it is necessary to stay in order to do further adjustments to the 'burn' by reducing the air flow to certain sections of the burn etc.
    5. In the final stage of the 'burn', the 'browning' can be accompanied by inlet ports 'pinking'. This is when the fire in the 'burn' reaches the edge of the kiln and the fire is drawn along the port. The 'pinking' is the tar residue that has formed during the 'browning' stage being burnt off. The resultant ash has a definite pinkish hue. This indicates that no further burning is required in this part of the kiln. The inlet in question should be covered over with a round slice of wood. When all 4 inlets have 'pinked' or are close to pinking, the chimneys can be changed for the last time.
    6. In the last stage, 4 inlets should have 'pinked' and now have chimneys on them. When the new inlets start to 'pink' it is time to 'close down' that section of the kiln/'burn', as it is complete.
    7. This is also the stage that point '7.'needs to be enacted (see '7' above).
    8. When 'closing down' the ports are to be paired, and treated as pairs-what is done to one is done to the other. Fill in the 'pinked' inlet and remove the chimney from the outlet next to it, filling this in also. The choice of which outlet to choose to make the first pair comes with experience, but as a guide, the kiln usually has a 'quick side' & a 'slow side' so choose a chimney that 'pinked' early when it was an inlet probably on the 'quickside' of the kiln.
    9. Another VERY important indicator of the final stage of the burn is the smoke. Once the smoke has changed from 'brownish' to 'whitish' then this indicate that the tars etc. that caused the 'browning' are thinning. This means that there is only charcoal in the kiln and the above 'closing down' steps should be followed. This stage may be more difficult to detect but comes with experience and produces the better quality charcoal.
    10. If the 'burn' is left longer than 'whitish', the smoke thins until it turns Blue - then clear. This has the following effects upon the charcoal inside:
      • The 'charge' becomes "fried", i.e. brittle to the touch, thus producing lower grade charcoal.
      • The yield is reduced as charcoal is burnt up creating round, white ashen 'hotspots' by the port inlets.
      • Ultimately, left too long, the 'charge'/charcoal, will simply consume itself completely.