The Four Numbers That Actually Matter Ash content. This is the residue left after the charcoal fully burns — essentially, the mineral and impurity content of the raw material. Premium coconut shell charcoal runs below 2.1% ash; lower-grade material or poorly carbonized batches often land at 3–4%. The practical effect isn't cosmetic: higher ash means more frequent relights, more residue buildup on grates or hookah bowls, and a shorter usable session per piece of charcoal. Moisture. Charcoal is hygroscopic — it pulls moisture from the air, and how much it started with matters. Export-grade product should sit at 5% or below. Charcoal above that threshold burns unevenly, takes longer to ignite, and produces more visible smoke in the first several minutes, which matters a lot for a shisha session where the first ten minutes set the tone. Fixed carbon. This is the percentage of the material that's actual combustible carbon, as opposed to volatile compounds that burn off quickly or ash that doesn't burn at all. Fixed carbon above 80% is the benchmark for premium coconut shell charcoal — it's the single best predictor of how long a piece will actually stay hot. Burn time. The number buyers actually care about, and the one the other three numbers exist to explain. 90+ minutes is the standard for briquette-format shisha charcoal; lump charcoal for BBQ typically runs 60–90 minutes. If a COA reports a burn time without also reporting ash, moisture, and fixed carbon, treat it with some skepticism — burn time is a downstream result of the other three, not an independent measurement. Why These Four Numbers, and Not Others Suppliers sometimes lead with secondary specs — calorific value, particle size, hardness — that sound impressive but don't map cleanly onto how the product performs for the buyer's actual use case. They're not meaningless, but they're not substitutes for the core four either. The full specification breakdown in our coconut charcoal buyer's guide walks through the complete spec table, including where hardness and binder ratio fit into the picture for briquette-format product specifically. The Template Problem Here's the part that catches first-time importers: a spec sheet and a COA are not the same document, and suppliers rely on buyers not knowing the difference. A spec sheet describes what a supplier's product is supposed to achieve — it's marketing material, even when it's formatted to look technical. A COA reports what a specific batch actually measured at, usually with a batch number, production date, and testing date attached. If a supplier sends you a document with no batch reference, no date within the last 30 days, and numbers that read suspiciously like round marketing figures (exactly 2.0% ash, exactly 80% carbon, on every single document they've ever sent), you're looking at a template, not a COA. The fix is simple to ask for and surprisingly effective at filtering suppliers: request a COA tied to a specific shipment that's already left the factory, not one generated on request. A manufacturer that tests every batch as standard practice can produce this in a day. A trading agent sourcing from whichever factory had capacity that month often can't — because they don't control the production line generating the data. COA Is Step One, Not the Whole Process Reading a COA correctly tells you whether a specific batch meets spec. It doesn't tell you whether the supplier can produce that quality consistently, whether they actually own the production facility, or whether their documentation for export (phytosanitary certificates, legality verification, safety data sheets) will hold up at customs. Those are separate questions, and skipping them is how buyers end up with one great sample shipment followed by three inconsistent ones. For importers building out a full supplier vetting process — not just reading one document, but structuring the whole evaluation — our 10-point manufacturer verification checklist covers the other nine checks worth running before committing to a full container order.