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When it comes to food storage as part of your plan for any long-term emergency and food security, freeze-drying and dehydrating are two of the top processes that come to mind. But what makes them different from each other? Also, which one is better?
Let’s take a closer look at the differences between freeze-dry vs dehydrated to see which process you should use for food storage. We’ll compare them in terms of taste, nutrition, shelf life, and cost.
Main Differences Between Freeze Dry Vs Dehydrated
- Freeze-drying involves the use of a large freezer through a process that relies on freezing, primary drying, and secondary drying, whereas dehydrating food uses a heating element, vents, and fan.
- Freeze-dried foods have up to 99% less moisture than their original content, whereas dehydrated foods only have 90 to 95% less moisture.
- Freeze-drying retains most of the food’s flavor, making them taste better, whereas dehydrating makes it lose its natural flavor.
- Freeze-dried foods retain up to 97% of their nutrition, whereas dehydrated foods retain only up to 60%.
- Freeze-dried foods retain their original appearance and texture, whereas dehydrated foods are prone to shrinking and getting leathery.
- Freeze-dried foods can last up to 25 years, whereas dehydrated foods can last up to five years.
- Freeze-dried foods are expensive, whereas dehydrated foods are cheap.
Process
One of the biggest differences between the two is how you will prepare them. Both will remove water from the food. For freeze-drying, the process is technically known as lyophilization. It is a three-step process, which includes freezing, sublimation or primary drying, and desorption or secondary drying.
Freeze drying is a food preservation process that has been around since 1906, which was first introduced by Jacques-Arsene d’ Arsonval, a French scientist. It starts with freezing the food at an extremely low temperature, which is roughly -40 degrees Fahrenheit. It is a rapid process, which prevents the formation of ice crystals.
After freezing, the next is the first drying phase. The food is packed in a bag, the air is vacuumed, and heat is applied at low pressure. It can take up to a few days and will retain only roughly 5% of the moisture in food.
The last process in freeze-drying is the water removal phase. It removes any excess water that remains after the initial stage. It is again exposed to a high temperature at low pressure, which will result in having only 1% of the food’s original moisture content.
On the other hand, food dehydration utilizes a combination of vents, fans, and heating elements. They work together to circulate air and remove moisture in food. It starts with the heating element increasing the temperature inside the dehydrator. The fan, meanwhile, ensures even heat circulation for better moisture removal.
Speaking of the process, it is also worth noting that freeze-drying removes up to 99% of moisture while dehydrating removes only 90 to 95%.
Taste
The two also have a significant difference when it comes to taste. Freeze-dried foods, such as pineapples and peppers, can have more intense flavors compared to before processing. It removes most of the water and moisture, retaining the original flavor of the food.
In contrast, many dehydrated foods lose much of their flavor during the process. This means that it will taste different compared to its original flavor. The application of heat can also make it lose its flavor, which does not happen in freeze-drying.
The taste, however, will also depend on the food that is processed. For instance, dehydrated apples, pears, and bananas can taste like candy since the sugar is brought to the surface. For freeze-drying, plums, apricots, and peaches are some of the best options.
Nutrition
If you are conscious about the foods that you eat, then you are most probably concerned about the nutritional value of whatever you eat outdoors. Freeze-dried foods are healthier because they retain most of their original nutrients. Throughout the process, it removes only water and not the beneficial vitamins and minerals.
Meanwhile, dehydrated foods use heat, which diminishes the nutritional value of the food. It can result in up to 40% loss of nutritional value. By contrast, freeze-dried foods retain up to 97% of their nutrition.
Appearance and Texture
The differences in the process of freeze-drying and dehydrating also result in a significant difference in terms of appearance and texture. Freeze drying is a gentle process that relies on low temperatures. This means that the food will most likely retain its original appearance and texture. It is often crispy and airy when eaten.
On the other hand, since dehydrating food requires a heating element, it shrivels. The longer it is dehydrated, the more it shrinks. Hence, you can expect that the appearance and texture will be different from the original, even its size. Not to mention, it can also turn leathery, which will make it hard to chew.
Shelf Life
Freeze-dried foods are known for their longer shelf life. This is because it removes most of the liquid in the food, making it less prone to spoilage. Meanwhile, dehydrated foods retain a lot of their moisture content, which is also the reason for their shorter shelf life. On average, the shelf life of dehydrated foods is five years, and 25 years for freeze-dried foods.
Whether you have freeze-dried or dehydrated foods, proper handling and storage will ensure long shelf life. Keep them in an air-tight container and store them in a cool and dark place. Exposure to external elements will speed up its spoilage.
Cost
On average, freeze-dried foods are more expensive compared to dehydrated foods. This is because the freeze-drying process is more meticulous, requiring more effort and time. It requires 20 to 40 hours to freeze-dry foods in a single batch but dehydrating will take only one to 36 hours.
As for the equipment, a freeze drier can cost about $2,700. Meanwhile, a food dehydrator can be as cheap as $250.
Freeze Dry Vs Dehydrated: The Winner
Overall, freeze-dry is better than dehydrated. Freeze drying is a meticulous and expensive process, but it is worth it. They retain most of their original flavor, appearance, and texture. Not to mention, it also has a longer shelf life.
