Stranded on an island.

No pan.
No oven.
No cooking tools.

So how do you cook a fish?

This time, we used petrology and thermodynamics just to cook one wild fish.

The first problem isn’t the fire.

It’s the rock.

You can’t simply throw any random stone into intense heat.
Moisture trapped inside certain rocks can rapidly expand into steam during heating, increasing the risk of fracture.

So we select a dry, dense piece of basalt and turn it into a primitive cooking surface.

Once heated in the fire, the basalt stores thermal energy through its specific heat and thermal mass.

At approximately 350°C, a simple rock becomes a natural frying surface.

The moment the fish touches the basalt, surface moisture rapidly vaporizes.

Intense conductive heat begins changing the protein and collagen structure while browning reactions build a crisp exterior.

But there’s a problem.

Leave the fish on the 350°C rock for too long, and moisture escapes faster than heat can reach the center.

The result is dry fish.

So we introduce a second piece of primitive engineering:

a natural steam dome made from wet leaves.

Steam circulates inside the enclosed space, using latent heat and convection to drive energy toward the center while preserving the crisp exterior.

At a core temperature of approximately 62°C, the protein structure sets while the interior remains moist and flaky.

Finally, the fish is opened with an obsidian blade to inspect the contrast between the crisp exterior and the juicy white flesh inside.

In the end, all we really needed was one fish and one rock.

But choosing the right rock required petrology.

And understanding how that rock could cook the fish required thermodynamics.

Did we really need this much science just to cook one fish?

Probably not.

But we did it anyway.

Far more serious than necessary.
Surprisingly useful once you understand it.

Useless Cooking Science