The Physics of Cooking
Cooking is applied thermodynamics. Every recipe is really instructions for moving heat into food at the right rate — and the three heat-transfer modes each own different appliances.
Three modes of heat transfer
Conduction moves heat through the pan's metal into food touching it; convection circulates hot air in the oven and boiling water; radiation from the broiler element browns the top without contact. Great cooking matches the mode to the goal.
Water's huge specific heat
Water needs 4,186 J to warm 1 kg by 1 °C — enormous. That's why pasta water takes forever to boil but then holds temperature steadily, gently cooking the pasta.
Pressure raises the boiling point
A pressure cooker traps steam at ~2 atm, pushing water's boiling point to ~120 °C. Hotter water cooks food dramatically faster — the ideal gas law and phase equilibrium at work.
Browning needs high heat
The Maillard reaction (proteins + sugars → flavor) only runs fast above ~140 °C. That's why you sear meat in a ripping-hot pan and why boiled meat never browns — water caps the surface at 100 °C.
Try this yourself
- Boil two identical pots, one lidded: time the difference — the lid traps convection and radiation.
- Sear one piece of meat on high heat and steam another; compare the crusts.