Freeze drying removes moisture from food through sublimation, which turns water molecules into vapor. Freeze-drying food affects the structure more than other preservation methods, such as pickling or freezing, but the nutritional value and flavor remain intact. Because freeze-dried foods are so lightweight, they’re great for taking on hikes or storing in an emergency kit. Read on to learn more about freeze drying and processing using different freeze drying methods.
Foods that contain a large amount of water are best suited. Their structure remains intact after the process. These foods keep especially well: Fruits such as apples, bananas, berries, persimmons and pears. Vegetables like potatoes, peppers, carrots, sweet potatoes and parsnips. Once you’re comfortable with the process, try freeze-drying chicken breasts, cheese, and even whole meals like spaghetti with meat sauce. Any food that contains moisture can be preserved by freeze drying.
Food that is freeze-dried at the peak of its freshness or ripeness will definitely taste good when reconstituted. Fruits and vegetables should be freeze dried when they are in season and fully ripe. Meat should be freeze-dried immediately after cooking and preparation. Full meals should be freeze-dried once prepared and cooled. Don’t freeze-dry them after storing them in the fridge for several days, or they’ll taste like leftovers once reconstituted.
Berries and apples don’t need to be reconstituted – the freeze-dried version tastes good as is. Freeze-dried meat or spaghetti, on the other hand, must be reconstituted with liquid in order to become edible. Do not freeze-dry foods that cannot be freeze-dried. Bread is not a good choice for freeze drying because its texture depends so much on freshness. Cakes, cookies, and other foods containing yeast are not good candidates for freeze drying.
Prepare foods for preservation as follows: If applicable, wash and dry foods thoroughly. Cut the food into small pieces. Cut *apples, peppers, potatoes and other fruits and vegetables into small pieces so that moisture can escape easily.
Spread them out so they don’t clump together.
If possible, make sure the freezer doesn’t contain any other items. If possible, do not open the freezer while it is freezing. This slows down the freezing process and causes ice crystals to form on the food. If you have a freezer, use that. Food should be frozen at the lowest possible temperature.
Over the course of a week, sublimation takes place and all moisture is removed from the food. Check if the food is completely freeze-dried by removing a piece and letting it thaw. If it turns black, it’s not freeze-dried yet.
When the food is fully freeze-dried, place it in freezer bags. Squeeze out the air, seal the bags, and store in either the freezer, pantry, or your emergency kit.
Lay the bags flat so the food doesn’t pile up in one corner. l Squeeze out the air before sealing the bag. Make sure the bags are sealed airtight.
Cover the food with dry ice. wear gloves and long sleeves when touching the ice. If you have a lot of bags of groceries, alternate layers of dry ice and groceries until the cooler is full.
Cover the box with a lid after 6 hours. After 24, check if there is still ice in the box. When there is none left, the food is ready for storage.
Either store them in the freezer, in the pantry, or in your emergency kit.
Spread them out so the pieces don’t clump together.
If possible, there should be no other items in the freezer. Don’t open the freezer often while the food is freezing. This slows down the freezing process and causes ice crystals to form on the food. If you have a freezer, use that. Food should be frozen at the lowest possible temperature.
120 mtorr. Set the temperature to 10ºC. The sublimation process should be completed within a week depending on the parameters set. After a reasonable time has elapsed, examine one of the slices to verify that freeze drying is complete.
Place them in a bowl or saucepan.
When the water boils, remove it from the flame.
It will expand and absorb the liquid. If it seems to need more water, give a little more on top. Repeat this until the foods are fully restored.
The purpose of storing freeze-dried food is to reduce the activity of water and the liquid content so that microbial activity is blocked. The addition of a pack of silicone gel reduces the possibility of condensation and moisture inside the container.
Store the food in proper containers to prevent it from spoiling. Handle dry ice with care. It burns your skin when you touch it.