How to read a charcoal COA, line by line
By Mohamad Sinno, Charcoal Expert · Reviewed by Budi Dharmawan, Head of QC,
Ask AI for an importer brief:
Walked through on one of ours, so you can follow on the real document rather than a description of one: Beckjorindo COA 000957, 17 June 2026. Open the certificate and read down alongside.
1 · The header
Three things to find: the certificate number, the dates (received and tested are usually separate lines, and can differ by a day or more), and the holder — the company the sample was submitted for.
The holder line is the check most buyers skip and the one that catches the most. A report naming a different company than the seller is a trading house passing through someone else's document. So run it on us: both our Beckjorindo certificates are addressed to our registered office in Jakarta, and our production site is in Bogor.
That is worth understanding rather than glossing, because it is the shape most Indonesian exporters have: a laboratory addresses its report to the registered entity, which is an office, while the material comes from a site somewhere else. What you check is that the entity on the report is the entity you are buying from — not that the address on it matches the yard in the photographs.
A supplier who can explain a discrepancy on their own paperwork is in a different position from one who cannot — that is what the check is for. The row and its note are on our document library.
2 · The method column
Look for a method against each row, not one method for the certificate. On Beckjorindo COA 000957 the rows split: ASTM D1762-84 (Reapproved 2021) for moisture and volatile matter; the laboratory’s in-house IK.BPL.7.4 for ash (Point 6.3) and fixed carbon (Point 6.4).
A named laboratory in-house method is not a red flag. Accredited laboratories validate their own procedures under their ISO/IEC 17025 scope, and an in-house method with a reference number is a documented, auditable thing you can ask about. An unstated method is the red flag. A percentage with nothing beside it cannot be compared with any other supplier's percentage, and that is the comparison you are trying to make.
3 · The results table — and its basis
Four rows on a proximate analysis: moisture, ash, volatile matter, fixed carbon. Before reading any of them, find the basis — as received, or dry. The same material reports different numbers on each, and a figure compared across bases is not a comparison. On Beckjorindo COA 000957: moisture 3.06%, ash 1.58%, volatile matter 18.33%, fixed carbon 77.03%.
Then run the arithmetic: the four should add to about 100. Why that works, and what it means when it does not, is on fixed carbon and volatile matter.
4 · Validity
The certificate states its own validity period — on current certificates in this trade that is commonly 90 days from issue. Past it, the document is a historical record. It has not become false; it has simply stopped describing anything you are about to receive.
5 · The signature
A named signatory and a role. This is what makes the report attributable — and it is the line that makes the final check possible: contact the laboratory directly, quote the certificate number, and ask them to confirm it. Both of our laboratories print their own contact details on their reports, which is the reason we publish the PDFs rather than a summary of them. Do not take our transcription of a figure for the figure.
Red flags, and the one that is not
| What you see | Why it matters |
|---|---|
| "Typical" values instead of a batch number | A certificate identifies the material it tested. A column headed "typical" is a specification sheet wearing a laboratory's layout. |
| No signature and no named signatory | An unsigned report is a draft or a template. The signature is what makes it attributable to somebody at the laboratory. |
| Every result sitting exactly on the limit | Real measurements scatter. Four figures landing precisely on four contractual limits is a pattern worth asking about. |
| No method stated for any row | Without a method, a percentage cannot be compared with anyone else's percentage. This is the absence that actually matters. |
| No validity or issue date | A COA describes a moment. Undated, it cannot be placed against your shipment at all. |
Red-flag conventions above are generic industry practice as observed in trade and laboratory documentation, August 2026. They are heuristics for asking a better question, not grounds for rejecting a shipment.
Once you can read one
The next question is what it covers — what a certificate of analysis proves, and what it does not — and how to use it on a reorder: the reorder QC checklist.