To build a homemade freeze dryer, use a styrofoam cooler of the required size, and place dry ice in it. Then, alternate layers of food and dry ice in the cooler, and close the cooler for a few minutes to allow the food to freeze. Then, store the food in a regular freezer or in a pantry.
Ensure that the cooler does not contain a lot of empty space once the food is packed in.
When the freeze-dryer is to be used, put one layer of dry ice on its bottom, wearing gloves to protect from burns and frostbite. Place one layer of the food materials to be freeze-dried on top of the dry ice. Instead of stacking the food items, place them one beside the other.
Then, place a second layer of dry ice on the food items. Continue alternating layers of food and dry ice until the freeze dryer is almost full. Ensure that the final layer comprises of dry ice.
Now, close the freeze-dryer, and leave it for approximately 30 minutes. After this time period, check if the food materials are frozen completely. If they are not, leave them in the freeze dryer, and check at intervals of five minutes until the items are fully frozen.
Finally, place the food materials in a regular freezer until they are to be used. If the food is vacuum-sealed, store in a food closet or a pantry.