A freeze-dryer is a device used to preserve perishable items. Freeze-drying foods removes the water content from them and replaces it with a gas. Freeze-drying is a great way to retain the nutritional value, color, shape, and texture of foods. There are many different types of freeze-dryers that can be used to freeze-dry foods; however, most of them are extremely expensive. A less expensive option is to make your own freeze-dryer.
Purchase a styrofoam cooler, if you don't already have one. The size of the styrofoam cooler you need will depend on the size of the food that will be freeze-dried. The cooler should be small enough to pack the food in without a lot of extra space.
Place the lid on the styrofoam cooler and let it sit for about 30 minutes. Check the items that are being freeze-dried to see if they are frozen solid, if not put the lid back on the cooler and continue to check the items every 5 minutes. When the food items are frozen solid they should be removed and placed in a normal freezer until they are ready to be used. If the items have been vacuum-sealed prior to freeze-drying, they do not have to be placed in a normal freezer but can be stored in a pantry or food closet.