Freeze-drying is a preservation method with many applications across many industries. The process of freeze-drying, also known as lyophilization, involves completely freezing a sample and then removing all the water and solvents it contains under a vacuum. Food items, blood samples, and microorganisms are a few examples of samples that can be freeze-dried. Because of the vast applicability of the preservation techniques, there are different machines and tools of various sizes used to suit the intended purpose.
Freeze-dryer
Freeze-dryer is the machine used in freeze-drying and the various types are listed below.
Tray freeze-dryers
A tray freeze-dryer is a sophisticated freeze-drying machine that produces the driest food that stores for the longest time. A freeze-dryer does both the unbound and bound water removal (primary and secondary removals) with the product in place, thus making excellently dried products possible.
Rotary evaporators
This type of freeze-dryer is used chiefly for liquid products such as blood samples, tissue extracts, and pharmaceutical solutions.
Manifold freeze-dryers
A manifold freeze-dryer dries products that will be used in a short time. It can dry many small containers and the product within it to less than 5% moisture content. However, to remove all the water, one needs to heat the items to achieve secondary drying.
Vacuum Pump
The vacuum pump is used during the primary drying to lower the environmental pressure and create the perfect environment for sublimation.
Table
A table is necessary to hold the freeze-dryer. A sturdy, heavy-duty stainless steel table is recommended so the freeze-dryer can be comfortably seated.
Silicone Mold and Mats
Silicone molds are necessary when freeze-drying liquid products so they can freeze-dry completely. Silicone mats are placed on the metal trays to prevent the food items from sticking to the trays.
Draining bucket
This bucket collects the water extracted from the products.
Vacuum sealer
A vacuum sealer removes all the oxygen in the packaging bags so the product can remain completely dry.
Oxygen absorbent packet
As the name implies, it absorbs the oxygen in the packaging bags. People might opt for using only oxygen absorbents packets without vacuum sealing, while others use only the vacuum sealer—however, people who like optimum dryness use both the vacuum sealer and the oxygen absorbent packet.
Self-sealing bag
These bags store the final freeze-dried products. Alternatively, people also use metal cans and sealable containers.
Metal scraper
Some items freeze in a solid mass which might get messy to remove. Metal scrapers remove such things before packaging.
Rubbing alcohol
This is used to remove the build-up of fine metal shavings and residue that forms in oil-less pumps.
Plastic Totes
Plastic totes are used to organize freeze-drying supplies.
Hot pads
This is used to protect the skin from getting freeze-dried when removing the old products from the freeze-dryer.
Scale
A weighing scale is a necessary freeze-drying equipment used to weigh the product before and after freeze-drying to get an accurate value of the percentage of water removed.