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What is freeze drying and how do we do it.

"“The primary mechanism that allows for freeze-drying is sublimation, whereby ice is directly converted to water vapor, without passing through the intermediary stage of a liquid. Rather than through heating, this is done by removal of pressure so that the ice boils without melting. The result is a sample whose structure is largely preserved, which can be stored at room temperatures and pressures.”" www.wisegeek.com


All floral freeze drying machines work the same way; the flowers are frozen to around -30°C in a chamber which is then subjected to an almost complete vacuum. Under this vacuum, sublimation will commence; the icicles in the flowers & petals will be converted to water vapour, which is then attracted to an ice trap running at around -45°C to -50°C. Over the entire cycle, the chamber is very gradually brought up to room temperature, at a rate of a few degrees a day, so that by the end of the cycle the flowers are perfectly dry & preserved.
The machines we use are specifically designed for floral preservation by committed specialists; as an illustration, the main chamber of the machines can hold up to around 2,500 flower heads, 30 or so bouquets, or around 50 King Proteas.


The drying cycle takes around 12-20 days (or longer in extreme cases) during which the temperatures, vacuum & ice trap must be monitored several times a day.

“The primary mechanism that allows for freeze-drying is sublimation, whereby ice is directly converted to water vapor, without passing through the intermediary stage of a liquid. Rather than through heating, this is done by removal of pressure so that the ice boils without melting. The result is a sample whose structure is largely preserved, which can be stored at room temperatures and pressures.” www.wisegeek.com

All floral freeze drying machines work the same way; the flowers are frozen to around -30°C in a chamber which is then subjected to an almost complete vacuum. Under this vacuum, sublimation will commence; the icicles in the flowers & petals will be converted to water vapour, which is then attracted to an ice trap running at around -45°C to -50°C. Over the entire cycle, the chamber is very gradually brought up to room temperature, at a rate of a few degrees a day, so that by the end of the cycle the flowers are perfectly dry & preserved.

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The machines we use are specifically designed for floral preservation by committed specialists; as an illustration, the main chamber of the machines can hold up to around 2,500 flower heads, 30 or so bouquets, or around 50 King Proteas.

The drying cycle takes around 12-20 days (or longer in extreme cases) during which the temperatures, vacuum & ice trap must be monitored several times a day.

- See more at: http://www.petalmania.co.za/how-we-do-it/#sthash.LkB1iwhM.dpuf