Congélation

Congélation is the process of lowering the temperature of a substance below its freezing point, causing it to transition from a liquid to a solid state. This is a common method for preserving food by inhibiting the growth of microorganisms and slowing down enzymatic reactions that lead to spoilage. When water freezes, it forms ice crystals. The rate of freezing can affect the size of these ice crystals. Rapid freezing, often achieved through blast chilling or specialized freezing equipment, produces smaller ice crystals, which generally result in better quality retention of the frozen product, particularly in foods.

The freezing point of water is 0 degrees Celsius (32 degrees Fahrenheit) at standard atmospheric pressure. However, the freezing point of solutions, such as those containing dissolved salts or sugars like in food, is typically lower. Freezing requires the removal of heat from the substance. This is accomplished in a freezer, which operates by using a refrigeration cycle to transfer heat from the inside of the freezer compartment to the surrounding environment.

Beyond food preservation, congélation is also employed in various industrial and scientific applications. It can be used for the temporary storage of biological samples, in cryotherapy for medical treatments, and in construction for ground stabilization. The energy required to freeze a substance and the subsequent energy needed to keep it frozen are important considerations in its practical application. Thawing, the reverse process, involves raising the temperature above the freezing point, returning the substance to its liquid state.