Kogning

Kogning is the process of heating a liquid to its boiling point and maintaining a state in which vapor forms rapidly. The term is used in Danish and Norwegian to describe boiling. Boiling is a form of vaporization driven by heat and occurs when the liquid’s vapor pressure matches the surrounding pressure.

The temperature at which a liquid boils depends on pressure and the liquid’s properties. Water at standard atmospheric pressure boils at 100°C, while other liquids boil at different temperatures. Boiling involves the nucleation of bubbles within the liquid, which rise to the surface and release vapor.

In practical use, kogning is common in cooking and food processing. A rolling boil is characterized by large, continuous bubbles; simmering is a gentler state with smaller bubbles just below the boiling point. In scientific and industrial settings, boiling is used for pasteurization and sterilization, for distillation, and to drive heat transfer or chemical reactions.

Equipment and safety: boiling is performed in pots, kettles, beakers, or reactors. To prevent boil-over, avoid overfilling and monitor heat levels. Handling hot containers requires caution to prevent scalding; using lids can reduce evaporation but may increase heat retention.

Variations: boiling at atmospheric pressure, or under pressurized conditions in autoclaves or reactors, increases the boiling temperature; vacuum boiling lowers the boiling point.