Desikointiin

Desikointi, or desiccation, is the process of removing moisture from a material or environment to reduce water activity and slow or stop chemical and biological processes. The aim is to achieve a stable, low-moisture state that can extend shelf life, preserve structure, or prepare samples for analysis. Water exists in free and bound forms, and desikointi typically targets the removal of free water first, followed by more tightly bound water as needed.

Common methods include natural air drying in controlled conditions, where temperature, humidity and airflow influence the rate; active drying using heat, forced air, or moisture removal devices; vacuum drying to remove moisture under reduced pressure; and freeze-drying (lyophilization), which freezes the material and removes water by sublimation under vacuum, preserving heat-sensitive materials. Desiccants such as silica gel, molecular sieves, or anhydrous salts are used in sealed containers to maintain a dry atmosphere.

Desikointi has applications across several fields. In the food industry, it enables shelf-stable dried products. In agriculture and horticulture, it is used to dry seeds and plant material while aiming to retain viability. In pharmaceuticals and biotechnology, drying powders and biological samples aids storage and handling. Microbiology relies on desikointi to preserve cultures, often via lyophilization. In electronics and materials science, drying reduces moisture-related corrosion and adhesion problems.

Key measurements include moisture content (MC) and water activity (aw), which indicate dryness. Standard methods include oven-drying for MC and specialized techniques for aw. Care must be taken to avoid over-drying, which can damage sensitive materials or reduce viability, while insufficient drying can leave materials prone to spoilage or degradation.