The process to manufacture these foods is much more expensive than that of dehydrated foods so it is something that you can only purchase.
How Is Food Freeze Dried?
Freeze-drying is actually a three-step process that starts with the food being frozen.
In modern methods the food is then placed in a vacuum chamber under low heat. This makes the frozen water crystals in the food evaporate directly from ice to water vapor in a process called sublimation.
After this second step, the food then undergoes a third step called “secondary drying”, in which any remaining water molecules are removed under slightly higher temperatures.
The food is sealed in nitrogen for storage to prevent contamination from water or oxygen.
As far back as 1200 A.D., the Incas would freeze-dry potatoes (chuño) and a precursor to beef jerky (charqui) by placing the food on stone platforms at high-elevations to freeze it overnight and then dry in the daytime sun.
Is Freeze Dried Food Healthy?
Experts have actually found that in testing freeze-dried berries that they retained up to 90 percent of their anthocyanins — the compounds that give berries their color and are thought to prevent cancer.
Other nutrients, such as vitamins C and E and folic acid, can be somewhat depleted through the freeze-drying process.
But once the food is rehydrated, freeze-dried food is similar in nutritional value to fresh food. Diane Barrett, a Professor of Food Science and Technology at UC Davis, says that freeze-drying is “one of the best ways to preserve food.”
And even though many companies sell the Freeze-dried foods in large gallon containers they come in an assortment of sizes. These foods have been popular for years with outdoor enthusiasts. Many sporting goods stores like REI sell small, lightweight packets used by hikers and campers.
Is Freeze Dried Food Edible?
Once it is added to boiling water, freeze-dried foods can be reconstituted in just a few minutes. You can also rehydrate foods in cold water, but it requires nearly double the time to be fully re-hydrated.
Because it rehydrates so fast this type of food is great for an easy and quick meal during an emergency situation.
Many of the freeze-dried foods can also be eaten dry as a crispy chip or added to different recipes for a unique twist.
Benefits over dehydration:
Foods that are freeze dried are:
- Better flavor
- Have a lower rehydration time
When foods are freeze-dried, it’s like putting the foods in “suspended animation”.
During the process, fresh or cooked food is first rapidly frozen then placed in a vacuum. Because the water is removed from the finished product it is substantially lighter and more compact. This makes it a great option for emergency foods.
Almost any food can be freeze-dried. Specialized equipment is required though so it can be a costly option compared to dehydrating food in your own home.
Cell structure, nutrients, shape, and color are all preserved with this process because of this rapid change though so it allows the food to keep a “fresh” look and most of its nutrition.