Shisha Charcoal Quality: Specifications, COA Reading, Testing and Batch Consistency

The specs that matter, in one table

Six numbers describe a shisha charcoal shipment. Typical ranges are from current COAs; the premium bands below are the grades we sell against.

Ash content

Ash content is a laboratory measure of the mineral residue that remains after a charcoal sample has burned completely, expressed as a percentage of dry weight.

In shisha use, ash is what a lounge operator sees on the bowl and has to remove. Higher ash means more frequent cleaning, a thicker ash layer that insulates the coal from the tobacco, and less usable heat per piece. Ash colour is often used as a quick visual check, but colour alone does not measure ash content; only a laboratory test on a dried sample does.

Ash in coconut shell briquettes comes mainly from the shell itself, from sand or soil picked up before carbonization, and from the binder. Clean shell, good sieving after milling and a controlled binder ratio keep it down. Typical range for our product: 1.6–2.3 % by grade (Platinum 1.6–1.9 %, Super Premium 1.9–2.3 %), tested to ASTM D3174. When comparing COAs, check the test basis (dry or as-received) — the same charcoal reports differently on each.

Moisture content

Moisture content is a laboratory measure of the water held in a charcoal sample, expressed as a percentage of its weight as received.

Moisture matters twice. In use, wet briquettes take longer to light, can crack or spark as steam escapes, and give less heat. In trade, water is weight you pay for: every percentage point of moisture in a container is charcoal you did not receive.

Briquettes leave the press wet and are oven-dried to a target moisture before cooling and packing. They can take up moisture again in humid storage or transit, so a COA from the factory and a test at destination can differ. Typical range for our product: 6–8 %, tested to ASTM D3173. Ask for the sampling date on any COA, and store cartons off the floor in a dry warehouse.

Fixed carbon and volatile matter

Fixed carbon is a calculated value that represents the carbon left to burn as solid char once moisture, volatile matter and ash are accounted for. Volatile matter is a laboratory measure of the material released as gas when the sample is heated without air.

The two move in opposite directions. Higher fixed carbon generally means a longer, steadier burn; higher volatile matter means faster ignition but more smoke and smell during lighting, and a sign that carbonization was incomplete.

Fixed carbon is usually reported by difference: 100 minus moisture, ash and volatile matter. That means an error in any of the other three numbers shows up here too. Typical ranges for our product: fixed carbon 75–85 %; volatile matter 12–15 %. Check that the four proximate values on a COA add up to 100 on the same basis.

Calorific value

Calorific value is a laboratory measure of the heat released when a kilogram of the sample burns completely, reported in kcal/kg.

For shisha charcoal, calorific value indicates how much heat a piece can deliver, but not how evenly it delivers it. Two products with similar calorific values can behave very differently in a bowl because of density, size and ash.

Calorific value rises with fixed carbon and falls with moisture and ash, so it is best read alongside those figures rather than on its own. Labs report gross or net values and on different bases; compare like with like. Typical value for our product: 7,200–7,500 kcal/kg. A figure on a sales sheet without a lab name, method and date is a claim, not a measurement.

Burn time: how "90–120 minutes" must be measured

Burn-time figures circulate in the trade without the test set-up behind them, which makes them impossible to compare. A burn time is only meaningful when these conditions are stated:

• Cube size — a 26 mm cube carries more charcoal than a 25 mm cube and lasts longer under the same conditions.
• Device — a foil bowl, a heat-management device and an open grate expose the coal differently.
• Airflow — draw rate and room ventilation change how fast the coal burns.
• Number of pieces — three cubes together burn differently from one alone.
• Ignition method and time — how long the coal was lit before the clock started.
• End point — when the coal stops giving usable heat, not when the last ember dies.

Our burn-time figures, measured with 3 cubes on a standard bowl in a 3-person active smoking session: 25 mm 80–120 min; 26 mm 95–130 min; hexagonal 90–150 min depending on size. Smoking time depends on smoking activity, the number of people, intensity, weather and wind. In laboratory conditions the same coals burn for more than 4 hours.

Reading and verifying a COA

Confirming a report with the issuing lab

1. Check the laboratory name, address and accreditation number on the report.
2. Note the report number, sample ID and sampling date.
3. Contact the laboratory directly, using contact details from its own website, not from the report.
4. Ask the lab to confirm that the report number exists and that the results match.
5. Check that the sample description matches the product and batch you are buying.

Tests you can run on a sample

Run these in order on the same sample box. Record cube size, device and number of pieces each time.

1. Burn: light pieces the way your customers do and time them to the end of usable heat.
2. Drop: drop unlit pieces from a fixed height onto a hard floor and count breakages.
3. Ash: weigh the residue after a complete burn and note its colour and whether it holds shape.

Batch-to-batch consistency

A sample proves the sample. Consistency comes from three controls: a retained sample from each batch kept at the factory so any claim can be checked against the same charcoal; a COA per batch on request; and a golden-sample clause in the contract.

A golden-sample clause names an approved sample, sealed and kept by both sides, and states that shipments must match it within agreed tolerances. We keep a retained sample from each batch for 12 months, and a COA is issued per container, free of charge.

Reorder checklist

• Quote the batch or COA number of the last approved shipment.
• Confirm the same size, packaging and print designs.
• Request a per-batch COA before paying the balance.
• Compare against your golden sample on arrival.
• Record results so trends show up across orders.

Our in-factory QC checkpoints

1. Quality control covers production and packing; request the shipment COA and inspection records.

Troubleshooting

Quality FAQ