Pressure cooking
Pressure cooking uses steam trapped in a sealed vessel to raise water’s boiling point, letting food cook at temperatures above ordinary boiling.
Pressure cooker: A sealed pot designed to cook food with steam under pressure. Its locked lid traps steam, creating the conditions that define pressure cooking.
Thermodynamics: The study of heat, work, energy, and the properties of matter. Pressure cooking applies thermodynamic relationships between pressure, temperature, and phase changes.
Pressure canning: A food-preservation process that heats sealed jars under pressure to destroy dangerous microorganisms. It uses similar equipment, but its goal is validated shelf-stable preservation rather than meal preparation.
Denis Papin: A French-born physicist and inventor who developed an early steam-pressure cooking vessel in the seventeenth century. His 1679 steam digester established the principle behind later pressure cookers.
Vapor pressure: The pressure exerted by a vapor in equilibrium with its liquid or solid. Steam pressure rises as the sealed cooker heats, allowing its interior temperature to climb.
Phase diagram: A graph showing which phases of a substance are stable at different temperatures and pressures. Water’s phase behavior explains how liquid water and steam coexist inside a cooker.
Legumes: Plants in the pea family, including beans, lentils, and chickpeas, whose seeds are widely eaten. Pressure cooking softens dried legumes rapidly without requiring prolonged stovetop simmering.
Steam digester: A sealed vessel invented by Denis Papin for cooking and softening materials with pressurized steam. It was the early pressure-cooking device from which the modern appliance developed.
Boiling point: The temperature at which a liquid’s vapor pressure equals the surrounding pressure. Higher pressure raises water’s boiling point and the temperature available for cooking.
Specific heat capacity: The heat required to raise the temperature of a unit mass of a substance by one degree. It helps explain how quickly water and food warm as the cooker heats.