Freeze drying food is a popular preservation technique. It is a great way to preserve homegrown fruits and vegetables as it will save you money and time in the long run. Freeze dried products also retain their nutritional value and taste for a long period of time (up to several years).
Defining Freeze Dried
Freeze drying combines two factors: very cold temperatures and low pressure. When combined, these work together to prevent food from spoiling. The fundamental principle is called sublimation, a shift from a solid into a gas.
Benefits of Freeze Dried Foods
Freeze dried foods have a long shelf life. They also require minimal preparation and revitalize quickly. In addition, the total weight of the product is reduced because 98 percent of the water is removed from the food. This makes it easy to store and to carry, if necessary.
Advantage to Freeze Drying Foods at Home
Freeze drying can be done in two ways: high-tech or low-tech. If you are trying this at home, low-tech is the clear choice as you will not possess expensive freeze drying equipment needed for more high-tech procedures. Your refrigerator will act as your primary tool. While the process for freeze drying foods at home may take longer, it is much more economical than buying prepared freeze dried foods or purchasing the equipment.
Determine the Product (s) to Freeze Dry
If you are just starting out, potatoes and apples are good products to start with. Pick the fruit or vegetable at the height of its ripeness and then wash the product.
Freeze Dry the Food
Find a mesh metal tray. The tray should have some holes or the freeze-drying process will take longer. These can be found at any restaurant supply store. Next, cut the apple or potato into very thin slices. The thinner the slice, the less time the process will take. Arrange the slices on the tray and place in freezer. Within 30 minutes, they should be frozen. Keep in freezer for about one week to completely dry. To test, remove one slice and thaw. If it is not completely dry, it will turn black. If this happens, keep slices in freezer for another day or two and test again.
Store the food
Once you have determined the food is completely dry, place it in an air-tight container or zip lock bags. If you have a home version of a vacuum-pack sealer, use that. If you do not, you can simply suck the air out of the bag with your mouth and press down firmly on the bag to remove any air bubbles. Then place in freezer and store until you need it. You can reconstitute them by placing them in hot water. Apples can also be eaten in their freeze-dried state.