Whether you are stockpiling food for emergencies or want backpacking meals, freeze dried food is almost always the best way to go. Freeze-dried foods are lightweight, can last decades, are easy to rehydrate, and taste good.
However, there is one little problem: buying freeze dried foods can cost a fortune.
But did you know that you can freeze dry food at home?
There are now some models of home freeze dryer machines available. If you want to try this at home, here’s what you need to know (including whether it’s worth the cost!).
What Is Freeze Drying?
We know that ice (a solid) can turn into water (a liquid) and then into vapor (a gas). However, in certain circumstances, ice can completely skip the liquid form and turn directly into a gas.
This process of a solid turning directly into a gas is called sublimation.
Freeze drying uses sublimation to remove water from food. The scientific name for this food preservation method is lyophilization.
History of Freeze Drying
Some cultures have utilized sublimation as a natural food preservation method. For example, the people of the Andes Mountains used sublimation to preserve meat and crops as far back as 1200AD. The conditions in the high-altitude Andes Mountains meant that the food froze, then the frozen water in the food slowly sublimated.
During WWII, freeze drying was used to transport blood and organs. Later on, freeze drying was industrialized and used for food. (Sources: 1, 2, 3, 4)
Chuño: Andean freeze dried potato.
Instant coffee is one of the most common freeze dried foods.
Growing up, I ate “astronaut ice cream” made by freeze drying
Freeze Drying At Home
You can preserve food at home in as little as 20 hours with a freeze dryer machine.
The process works like this:
- You put food into the freeze dryer chamber.
- The machine flash freezes the food, so the water inside it turns to ice. Harvest Right units go to -30°F or colder.
- A pump removes air from the chamber, creating a vacuum.
- Because pressure is low inside the vacuum, the ice turns into vapor.
- A low-temperature condenser pulls the vapor out of the chamber.
When the process is over, you will have food that is free of water and chemically stable. So long as you keep the food in ideal conditions, it can last up to 25 years.
A good home freeze dryer machine will self-monitor the process. Once the water vapor has been removed, the humidity sensors automatically turn off, so the method is…
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