Pressure cooking changes the environment around the rice.
Inside a sealed Instant Pot, pressure raises the boiling point of water. This allows the rice to cook at a higher temperature than it would in an open saucepan, so water moves into the grain and the starch gelatinizes more quickly.
Why Natural Release?
The timer reaching zero doesn't mean everything happening inside the grain suddenly stops.
The rice is still extremely hot while the pressure gradually falls. During this period, heat and moisture continue moving through the grain.
Think of the natural release as part of the cooking process, not waiting time.
Pressure cook → natural release → open → fluff or fold.
