The exact recipe for Greek fire is not known today, and that was very intentional on the part of the Byzantines, who treated it as a tightly guarded state secret.

What Greek fire likely was

Historians can only reconstruct probable ingredients based on descriptions, later manuals, and experiments.

Most modern scholars think it was based on a petroleum-type liquid, thickened and made more adhesive:

  • Light petroleum or naphtha as the main fuel.
  • Resins such as pine or cedar resin to make it “sticky” and help it cling to ships and men.
  • Pitch or bitumen as additional flammable, tar-like material.
  • Sulfur to help ignition and boost flame intensity.
  • Possibly quicklime (calcium oxide) or similar chemicals, which react exothermically with water and may have helped it ignite or keep burning even on the sea.

Because it burned on water, spread across surfaces, and was very hard to extinguish, many researchers compare it to a kind of early napalm-like mixture rather than to gunpowder.

How it was used in battle

Greek fire was not just a mixture; it was a whole weapon system.

  • It was famously used by the Byzantine navy from the 7th century onward, especially in sea battles against Arab fleets.
  • The liquid was kept in heated, pressurized containers on ships and then pumped through bronze tubes or siphons mounted on the bows, spraying a burning jet onto enemy vessels.
  • Some sources also suggest smaller versions in handheld siphons and ceramic grenades or pots that could be hurled and burst into flame on impact.

Contemporary accounts say water could not put it out; defenders had to smother it with sand, earth, or use vinegar and similar substances.

Why the formula is “lost”

The Byzantines treated Greek fire as a core strategic advantage, so:

  • Knowledge of the exact method was restricted to a small circle of specialists serving the emperor, possibly a single family line associated with the inventor Kallinikos of Heliopolis.
  • The empire fell piece by piece, and the technical tradition broke; no surviving document clearly and reliably spells out the full formula and method.

Medieval and later “recipes” for similar fires exist, but historians debate whether any of them capture true imperial Greek fire or are just imitations inspired by its reputation.

Modern reconstructions and debates

Scholars and experimental historians have tried to reconstruct how Greek fire worked:

  • Reconstructions using crude oil plus resins, heated and pumped through a bronze nozzle, can produce a powerful burning jet with temperatures above 1,000°C and a short but deadly range (around 10–15 meters).
  • These tests support the idea of a pressurized, petroleum-based projector weapon rather than a simple thrown oil pot.

However:

  • Different ingredient combinations can produce similar effects, so experiments cannot uniquely identify a single “correct” recipe.
  • Many details in medieval texts are vague, symbolic, or distorted by time, making it hard to separate practical formulae from later legend.

Bottom line: “How was Greek fire made?”

Putting it all together, the best historically grounded answer is:

  • Greek fire was likely made from a light petroleum base (naphtha or similar) thickened with resins, pitch/bitumen, and enhanced with sulfur and possibly quicklime or related chemicals.
  • It was heated, kept under pressure, and expelled through bronze siphons, then ignited at the nozzle to create a continuous stream of burning liquid that could stick to ships and burn even on water.
  • The precise proportions, preparation steps, and ignition system remain unknown, so any modern “recipe” is ultimately an educated reconstruction rather than the original Byzantine formula.

Information gathered from public forums or data available on the internet and portrayed here.