Several steps are required :
- The first step is to freeze the product between -30°C and -50°C, transforming the water present into ice.
- The ice is then sublimated, i.e. transformed into a gaseous state (water vapour), in a vacuum set to -20°C.
- The final phase is known as ‘final drying,’ a drying process carried out at +37°C to extract all residual water from the product.
Freeze-drying results in dehydrated products with a low moisture content of 1-2%.