Freeze drying (lyophilization) takes place in a large machine
called a FREEZE DRIER, where all the contents are frozen to a
very low temperature & then a vacuum pump removes the
moisture. The specimens are solidly frozen during the process,
shrinkage is minimized & very good preservation should
result.
The
basic elements of FREEZE DRYING have been known for over 70
years. However it was not until the second world war that the
process was refined to supply large quantities of dried blood
plasma & penicillin to the armed forces. Today we all know
of FREEZE DRIED coffee or food for camping or expeditions.
Since
FREEZE DRYING of botanicals began in 1989, it is still too
early to say that FREEZE DRIED flowers will last forever (even
we don't last for ever!). However when protected from
humidity, full sunlight & insects, FREEZE DRIED flowers
& vegetables should last for years. The shape should stay
the same but over the years the colours will take on an
antique effect. Not all flowers or vegetables are suitable for
FREEZE DRYING & unfortunately the process cannot be
achieved in a normal fridge or freezer. You need a vacuum pump
& extremely low temperatures to produce a good result.
At
HEDGEROW FLOWERS, flowers such as roses, daffodils, camellias
pansies or paeonies & even mushrooms, small pumpkins,
strawberries, sweet corn, broccoli & brussels sprouts have
been FREEZE DRIED. The odd mouse, ice cream, frog cake &
sausages are sometimes preserved by FREEZE DRYING to be used
in arrangements, or just for fun!
Archival
material, scientific specimens & other unusual things are
now an interesting part of the business.
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