Freeze Drying
![Picture](/uploads/2/9/0/9/29093339/7497501.jpg)
Basic Principles:
Sublimation is the main principle behind freeze drying.
During sublimation, the water present in our products would transition directly from the solid phase to a gas phase. This occurs in an environment that is at a low temperature and a reduced pressure, such as a vacuum.
Sublimation is the main principle behind freeze drying.
During sublimation, the water present in our products would transition directly from the solid phase to a gas phase. This occurs in an environment that is at a low temperature and a reduced pressure, such as a vacuum.
![Picture](/uploads/2/9/0/9/29093339/4373037.jpg)
Basic Process for Freeze Drying:
Results:
- For optimal drying, increase the surface area of the product by cutting it up into smaller pieces and spread out into a single layer. Freeze product before putting into freeze drier.
- After the product is added and the freeze drier is turned on, the temperature decreases to -40°C and the pressure is decreased and a vacuum is formed. This is were sublimation takes place.
- The water vapors in the machine transfer onto the condenser which is at a temperature of -100°. This temperature causes the water to change from the vapor phase into the solid phase, and collects the vapors as solid ice.
- After drying, the vacuum is slowly released and the solid on the condenser is allowed to defrost.
- The freeze-dried product can be run through the machine again if needed and must be stored in a sealed container to prevent re-absorption of water.
Results:
- Veggie Burger: 50.6% water
- Spinach Dip: 75.9% water
- Pickled Herring: 49.0% water
- Dried Seaweed: 0% water (gained weight during time out of packaging)