How Charcoal Burn Time Is Measured

Burn time is one of the most quoted and least comparable charcoal numbers, because it is entirely method-dependent. The same briquette can show a very different burn time depending on how much you light, how big the pieces are, how much air reaches the fire, and where you decide the burn has “ended.” A burn-time figure without its conditions is marketing, not data.

What Changes The Number

Test variables that move a burn-time figure Method / source: State every variable below alongside any burn-time claim, or the number is not comparable.

Variable	Why it changes burn time
Piece size & shape	Larger, denser pieces burn longer; hexagonal vs pillow differ at equal mass.
Mass / quantity lit	More charcoal sustains heat longer — compare equal masses only.
Airflow / vent setting	Open vents burn hot and fast; restricted air extends the burn.
Ignition method	Chimney, electric, or accelerant changes the warm-up profile.
End-point definition	Time to "below cooking heat" differs from time to fully extinguished.
Ambient conditions	Wind, temperature, and humidity all shift the result.

How We Measure It

We log burn time as part of a timed burn test: a stated mass of a stated shape and piece size, lit a stated way, with mass and surface temperature recorded at fixed intervals (1 / 5 / 10 / 20 / 30 / 45 / 60 / 90 minutes). Because every published value carries its conditions, two of our figures can be compared like-for-like — and our own measured numbers are published only from that accredited test, never quoted from a benchmark.

Burn time is closely tied to fixed carbon and calorific value: more fuel and more energy per kilogram generally mean a longer, hotter burn. See calorific value for the energy side of the picture.

Questions

Why do two suppliers quote such different burn times?

Usually because they measured under different conditions — piece size, mass lit, airflow, and end-point definition all change the number. A burn-time figure is only comparable when those conditions are stated, so always ask for them.

What conditions should a burn-time figure state?

At minimum: the piece size and shape, the mass lit, the ignition method, the airflow/vent setting, the end-point definition, and the ambient conditions. Without these, the number cannot be compared across products.

Does longer burn time always mean better charcoal?

Not on its own. Burn time has to be read together with heat output and consistency. A long, weak burn is not better than a steady burn that holds cooking heat; coconut-shell briquettes are valued for holding heat for a long, even window.