The Science of Heat Transfer in the Kitchen

Heat control is one of the most important jobs for a cook. A lot of cooking mistakes can trace their roots to misunderstandings about heat: how it's generated, how it changes over time and space, and how to control its flow.

What is heat? Heat is thermal energy in transit. It’s not stationary thermal energy, nor is it a measure of the energy (that would be temperature). Heat is a dynamic concept. It’s probably easier to always think of heat transfer instead of just heat.

The three modes of heat transfer are conduction, convection, and radiation. Heat transfers by conduction in a stationary medium. A common misunderstanding is that convection is how heat transfers in a fluid. Actually, convection occurs when heat transfer takes place between a surface and a moving fluid. Finally, if there is no medium between the heat source and the object receiving the heat, like between the sun and the earth, heat transfers by radiation. We will first study conduction and convection by cooking a soft-boiled egg, then radiation by making a toast.