The freeze-drying process

Freeze-drying is the only way to successfully extract moisture from a flower, and is a complicated process which requires a lot of professional skills. One small mistake can quickly damage the product. Sweet Colours has the most modern machines which run 24-7 and are operated by unique software. Before the process begins, the roses and hydrangeas are cut off (just underneath the head) and placed in drawers in the machine.

The freeze-drying machine and process
The machine consists of two chambers: the condenser chamber and the specimen chamber. Once all the roses have been placed in the specimen chamber, the machine is started and the freezing programme begins whereby the roses are frozen to -40 degrees. Then the vacuum pump comes into operation and the actual drying process commences. Because the condenser chamber is colder than the specimen chamber (-55 or less!) the vapour is extracted from the roses under a deep vacuum and converted into ice-crystals. These ice-crystals quickly form a layer of ice in the condenser chamber. The ice is removed by defrosting. When no more ice forms, the process is complete and the specimen chamber can be opened (always a nice moment). The whole process takes about 14 days. By carrying out this process with great care, Sweet Colours is able to produce perfectly freeze-dried rose petals, hydrangea petals and delphinium petals which can be used directly.