Testing shisha charcoal

By Mohamad Sinno, Charcoal Expert · published 7 September 2026. Not reviewed by the Head of QC — the reviewer byline on our older quality pages carries the date those pages were read, and this one has not been read yet.

Three tests separate a sample you can judge from a sample you can only admire: burn it, drop it, and look at what it leaves behind. All three are runnable on a warehouse bench. None of them has a current, public, charcoal-specific standard behind it — and knowing that is worth more than any of the three.

The three tests, in order

Run them in this order, because each one destroys the sample for the next. Drop first while the piece is cold and whole; then burn; then read the ash. Take more pieces than you think you need — one piece tells you about one piece.

Each has its own page with the procedure written out: the drop and shatter test, the burn test method, and what ash colour does and does not tell you.

The standards layer, read at the issuers

This is the part every supplier page skips, and it is the reason their pass/fail thresholds cannot be checked against anything.

ASTM D1762-84 is the only charcoal-specific method in the family, and its scope is public while its procedure is not. In ASTM's own words: "This test method covers the determination of moisture, volatile matter, and ash in charcoal made from wood. The test method is applicable to lumps and briquets and is designed for the evaluation of charcoal quality." (ASTM D1762-84 (2021), scope statement, store.astm.org). That is §1.1. Everything after it is paywalled, so no page — including this one — can tell you what the procedure says. A supplier quoting D1762 steps at you has either bought the standard or is inventing them.

The drop tests in the catalogue are not charcoal tests. ASTM's current coal-and-gas standards list carries D440-07(2019)e1, Standard Test Method of Drop Shatter Test for Coal and D3038-93(2018), Standard Test Method for Drop Shatter Test for Coke. Titles, and the titles say coal and coke. The family a briquette buyer is pointed at was written for a different fuel.

The one charcoal-specific procedure manual in general circulation is forty years old. The FAO's quality-control chapter sets out a moisture determination — dry at a constant 105 °C for three hours, then reweigh at one-hour intervals "until the loss is not more than 0.25% in one hour's drying" — and points at the drop shatter test as "ASTM D440 -49. Used for charcoal briquettes". It also warns that volatile-matter samples must be crushed by hand, because "the heat generated would already drive off part of the volatiles" (FAO Forestry Paper 63, Industrial charcoal making, Rome 1985). It is good procedure and it is still the best free source. Its ASTM designations are 1985 vintage — D440-49 against today's D440-07(2019) — so cite the procedure, not the numbers.

What our own reports actually used

Against that background, here is the honest accounting of our own certificates — and it is not a clean sweep.

Two of the four values we publish rest on a method nobody outside that laboratory can read. That is normal in this trade and it is not a defect — but it is a fact about the comparability of an ash figure, and a supplier who prints "ASTM" against all four rows on a certificate that says otherwise is telling you something the document does not. The full method line, as printed: 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). How to check any of it is on verifying a lab report.

Bench setup, and the sheet we cannot show you

What a bench test needs is unglamorous: a scale that reads to a tenth of a gram, a hard tiled or concrete surface, a clean white dish, a timer, a way to light a piece the same way twice, and somewhere to write down what you did before you write down what happened. Photograph the carton code first. A test whose conditions you did not record is an anecdote.

What we do not have is a scored sheet from one of our own batches to show you. The drying log and the container loading log are not published, and no sample page of either has been supplied. We would rather say that than publish an illustrative bench log with plausible numbers on it, which is precisely the sort of document this section is teaching you to distrust. What we can state is what the factory records, which is not the same thing as publishing it: ash content, moisture, burning time, drop test, cracks, temperature, per batch, plus weight, ash content, moisture, ash colour at 6 sampling stages.

Pass and fail, where we have a criterion

Two of the three tests have a written pass criterion here. One does not, and the gap is stated rather than filled.

The burn row is an open item on our own data sheet and we are not going to close it with a plausible sentence. The factory records burning time as one of the parameters in each batch file; the conditions under which it is measured — piece mass, how it is lit and for how long, foil or heat-management device, airflow, ambient, and what counts as the end — have never been written down for us to publish. Until they are, any duration we quoted would be a number without a method, which is the thing the burn-time page exists to argue against. The procedure a buyer can run in the meantime is on its own page.

When something fails here, the rule is short: the batch, or the failing part of it, is rejected and does not ship. There is no re-drying-and-retest route, because we do not run one.

When a bench test is not enough

A bench test settles handling durability, ignition behaviour and gross ash appearance. It cannot produce ash content, volatile matter or fixed carbon — those need a furnace, a balance that reads to four places and a method, which is what a laboratory is for. The escalation is a certificate for your batch, and then a laboratory of your own choosing if the certificate and your bench disagree. Those laboratory figures for our own charcoal, three reports with the method each row was run under, are on what our laboratory reports measured.

We name exactly one laboratory on this site, because we hold documents from exactly one, and that is on the certifications page with its accreditation number and the register to check it in. Some buyers re-test at laboratories of their own and report results consistent with our certificates; we hold no copies of those reports and do not name those laboratories, because "consistent" is their word and not a measurement of ours.