DESCRIPTION OF FREEZE-DRYING

Freeze-drying requires usage of a specialized machine. The top chamber of the machine shown will hold approximately 30 bouquets or 2500 rose heads.

When the flowers are placed in the freeze-dry machine, they enter a chamber with a temperature of approximately -30 degrees F.

At this point, special loading skills are required to best position flowers before being frozen to avoid being frozen in a non-desirable position. Physical placement in the machine (top, bottom, front, rear) is also very important for certain flower types.

Because they immediately begin to freeze, the flowers are not given the chance to wilt or change shape. Within a few hours they are solidly frozen.

Once the flowers are solidly frozen, the process of drying will begin. The frozen moisture is released into the chamber and is removed by a vacuum system. This is a long process sometimes taking as much as 30 days for a machine load of flowers.

When the chamber has reached the 0% humidity level, the machine is powered down and the flowers are ready for post treatments.

It should be noted that freeze-drying companies with less than FOUR freeze-drying machines most likely store your flowers in a chest freezer until the freeze dry machine is available for loading. Having four or more machines allows for a machine to be loaded weekly, as processing times are generally 4 weeks.
Transfer of the flowers from the chest freezer to the freeze-dry chamber can have drastic results, expecially for certain flowers such as orchids and lilies.

Although most flowers do well in the freeze-dry process, there are a few that we do not suggust for this process; bouvardia, iris, small daisies, lily of the valley, tulips, and wild-flower types.  It is best to consult us with any questions. 

BENIFITS OF FREEZE-DRYING

Freeze-drying is the best method to-date to retain the flower's size, shape, and color.

Other methods include:

• Air-drying (handing upside down in a dry place)
• Pressed (will be flat and not characteristic of the original)
• Silica sand or gel (can burn flowers easily, and make brittle)
• Cornmeal and borax (will not retain color)

Please see 'DATELINE'/GOOD HOUSEKEEPING MAGAZINE published on May 30, 1999 for an exclusive on preserved flowers.


HISTORY OF FREEZE-DRYING

The basics of freeze-drying were used by the Peruvian Incas of the Andes, who stored their foods on the heights above Machu Picchu. The extreme cold temperatures at that height froze the vegetables, and the water inside slowly vaporized under the low air pressure.

During World War II the process of freeze-drying (lyophilization) began commercially to preserve blood plasma that was needed on the front lines.

Since then foods have been freeze-dried for commercial use and also by NASA for the space program.

The preservation of florals did not evolve until the 1990's. This is primarily because the flowers needed treatments before and after the process to make them not prone to shattering and loss of color.

FUTURE OF FREEZE-DRYING

In regards to floral preservation, the pre-treatments and post-treatments continue to evolve today, making the flower's color stay close to original and give them longevity. Treatments are now being developed for specific colors.