Presently, museums, science, insurance and pharmaceutical companies, food processing firms, taxidermy and arts and crafts are the strongest professional sectors employing freeze-drying technology.
What is the freeze-drying process?
Also known as lyophilization, freeze-drying immobilizes an object, made of either organic or inorganic material, as it removes moisture while in a frozen state. The absence of water discourages the growth of microorganisms and prevents other chemical changes associated with spoilage. It is the most natural of heretofore known preservation processes and favors extended storage for items while retaining their original shape and structure, with shrinkage minimized, if not totally eliminated.
The ancient Peruvian Incas of the high Andes mountains knew of the rudiments of freeze-drying. They stored potatoes and other foodstuff above the Machu Picchu, where the cold temperature froze the tubers, and the water inside slowly vaporized under the low air pressure.
Originally introduced in 1813 by William Hyde Wallaston to the Royal Society in London, the procedure was then known as sublimation, or converting a liquid in a frozen state directly to a gaseous one. Other processes involving chemicals, cryogenics, sterilization, irradiation and dehydration were tried unsuccessfully, but freeze-drying emerges as the finest method for restoring an object to its original state.
The process was first commercially used during World War II, to preserve blood plasma and supply penicillin needed at the front lines. In the late 1970s, freeze-drying was applied to taxidermy, food preservation, museum conservation, and pharmaceutical production.
Many museums and libraries worldwide, like the Detroit Institute of Arts and the National Library of Australia, have harnessed the technology of vacuum freeze-drying for conservation purposes, including disaster recovery measure. Many of these institutions have spearheaded the training of staff and personnel on the technology.
"The prospect of coping with future large disasters using vacuum freeze drier technology appeared very attractive, less damaging and more easily managed compared to huge air-drying exercises," says Kim Morris, a paper conservator working as Collection Preservation Laboratory Manager in Preservation Services at the National Library of Australia.
Morris has worked in the conservation field for the past 12 years, mostly in cultural institutions based in Canberra. In recent years he has been involved in presenting disaster and library preservation workshops and has taught the conservation component of the Canberra Institute of Technology’s Cultural Preservation course.
Today, aside from having been found to be ideal for the recovery of water damaged items from fires or floods and the preservation of drugs, animals, and foods, freeze-drying, starting in the 1980s, is pleasantly applied to flowers, leaves and twigs in aid of crafting products for decoration.
It is probably an ancient desire to preserve – however fleeting – what is precious and beautiful that led to the practice of drying and preserving flowers. Pressing a flower in a book, or hanging roses upside down to dry are techniques that go back to ancient Egypt and Greece.
Artists would later discover using desiccants (drying agents like borax, silica gel or even sand) to arrest the shrinking of flower petals while they dried, resulting in a much more natural look. Though these techniques are still widely used today, they unfortunately have a serious shortcoming. The dried flowers become fragile and delicate, prone to shattering or breaking at the slightest touch.
It was the Freeze Dry Company that introduced the amazing concept of freeze-drying flowers in 1981 after years of research and development. Producing a dried flower with the beautiful color and shape of fresh flowers is a phenomenon that has taken the industry by storm. Endless creative and business applications for the process have been discovered by floral entrepreneurs worldwide, making freeze-drying the hottest business opportunity in the floral and crafts industry.
Le Gallerie de Fleur is now open at Le Rosh Freeze-Dried Florae Originals at Level 3, Glorietta, in Ayala Center, Makati City as a base to market the Freeze Dry Co. machines for industrial and home business use. Interested parties who want to avail of freeze-drying services may bring their materials, like water-damaged books, textiles, artworks, or documents, and other keepsakes, like wedding bouquets, personal effects, or mementos, to the store. The outlet will also serve as a showcase of freeze-dried floral items, for which the company has been known, for the last 10 years.
The freeze-drying machine consists of two chambers and a vacuum system. The top chamber contains 10 trays on which flowers are placed. Once this chamber is loaded, a cycle is started that freezes the flowers to -20° F. At the same time, the vacuum system begins to bring the top chamber down to a hard vacuum, which removes moisture from the flowers. The moisture transfers to the lower chamber, kept at -55° F, and reforms into ice.
The freeze-drying process usually takes 12 days to complete a cycle. After the moisture is removed from the flowers, the temperature in the upper chamber is slowly raised. By the final day, the top chamber is at 70° F. The flowers are back at room temperature, all moisture has been removed, and ready to be taken out of the machine. The flowers are inspected, and treatments are applied to help retain color, shatterproof and soften the freeze-dried flower.
As in most things, technology has come to the rescue with the marvelous technique of freeze drying that ensures an end product that is amazingly like the fresh flower.