VACUUM DRYING
The embedded plant material may be dried /dehydrated under vacuum. Vacuum is created in
a thick-walled chamber fitted with a heating device, a vacuum pump and a condenser. Low
temperature is very effective and the quality of the product is excellent.
FREEZE DRYING
Perhaps the most effective (realistic) method of flower preservation involves freeze drying. In
this process the flowers are placed into a refrigerated chamber and the temperature is lowered to below
freezing (-35°C). A vacuum is then created in the chamber, causing the moisture in the flowers to
sublimate, or change from solid to gaseous form. The water vapour is then collected in a separate
chamber and the dried flowers are allowed to slowly warm to ambient temperature. This process takes
several days, requires expensive equipment and is best left to professionals.