Many people have a common misconception about freeze-dried foods. They tend to believe that freeze dried is the same as dehydrated foods, however this is not true.
There’s a huge between the two starting from the way they are processed to the way they look and taste.
Both these foods are crucial for emergency situations/ survival preparedness as they can be stored for long. Despite a few similarities, freeze-dried foods are a lot different from dehydrated foods, let’s find out how.
What are the different processes involved?
Freeze-drying uses specialized equipment to remove the moisture contained in foods by freezing them and this process is known as lyophilisation. To enhance the storage or shelf life of foods, they are frozen and when moisture turns into ice, it is evaporated by placing the frozen food in vacuum.
Dehydrating foods on the other hand is a centuries-old process where foods are dried out by circulating dry or hot air around it. The moisture inside the food is completely dried out to prevent the food from getting rotten. The process uses high drying temperatures just enough to remove water and not alter the taste of food.
Freeze-drying is comparatively a modern process of creating emergency food supplies. The moisture in this case is turned solid and then evaporated in gas form, hence the food retains its natural taste and nutritional value.
What is the shelf life for these types of emergency foods?
The dehydrating process removes up to 95% of the moisture present in foods, while the freeze-drying format removes about 99% of the moisture. So, the shelf life of freeze-dried foods is higher than dehydrated foods.
The dehydrated products such as dried nuts and vegetables can be stored for 15 to 20 years. Some of these products such as salt, sugar, oats and wheat can last for about 30 years or may be even longer.
The freeze dried foods on the other hand can be stored for 25 to 30-years. They can be easily stored at different temperatures without being affected by external weather conditions.