Popcorn Popping Simulator (2D)

Heat

Stove power 70%

Kernel

Moisture content 13.5%

Pan is cold — turn up the heat.

Live Readout

Pan temperature

20 °C

Internal pressure

1.0 atm

Popped

0 / 32

Pop rate

How it works

Every popcorn kernel is a tiny pressure vessel: a hard, nearly waterproof starch hull (pericarp) sealed around a dense starchy endosperm that holds a few percent water by weight. As the pan heats the kernel, that trapped water heats too, but the sealed hull stops it from simply evaporating away — instead the water turns to steam inside the kernel, and steam takes up far more volume than liquid water, so pressure climbs fast.

The hull can survive a surprising amount of internal pressure before it fails — real kernels rupture at roughly 135°C internal temperature and about 9 atmospheres of internal steam pressure. The instant it gives way, the superheated water flashes to steam almost instantly, the pressurized starch inside gelatinizes and violently expands into foam, and the kernel turns itself inside out into the familiar fluffy white puff — all in a few milliseconds.

Moisture content controls how well this works: kernels near the ideal 13–14% moisture build pressure quickly and pop reliably. Kernels that are too dry never build enough steam to rupture the hull cleanly (weak "duds"), and kernels that are too wet can vent moisture too slowly or fail to gelatinize evenly, also lowering the pop rate.