Freeze drying provides a tried-and-true method of preserving the flavour and texture of fruits, vegetables and even whole meals for years at a time. Unlike traditional freezing, freeze drying removes up to 98 per cent of the water from the food. Super-cold temperatures freeze the food very quickly, and the food can be rehydrated quickly using water. Dry ice is now readily available for the average household and can be used to make home freeze drying a possibility.
Obtain a cooler. Either a foam or plastic cooler will do. The size of the cooler entirely depends on the needs for which it is being used, but keep in mind it is important to completely fill the cooler, so either have enough food or dry ice to ensure that. Purchase dry ice and freezer bags.
Prepare food. Place the food into the freezer bags, removing as much air as possible before sealing. Place as much food into each bag as will be needed when rehydrated. If a countertop vacuum sealer is available, use it, but one is not necessary.
Layer dry ice with sealed bags of food. Make sure both the bottom and top layers in the cooler are dry ice. Try not to overlap bags of food so maximum surface area is touching the ice.
Close cooler and wait. If food is still soft to the touch, leave it in longer. Duration of freezing will depend on size and amount of food, but do not open the freezer before 30 minutes have gone by.
Decide on storage. If packages have been vacuum sealed, they can be placed in a pantry or cupboard. If not vacuumed sealed, they will not last as long, between six months and a year, and need to be put in a freezer.
Set cooler outside with the lid off. The dry ice will evaporate and leave just your freshly frozen foods. Be sure to do this once food is completely frozen.
Do not touch dry ice directly with hands as this can cause frostbite. Follow safety instructions regarding dry ice and be sure to use insulated gloves or tools to handle ice. Freezer bags may allow air in, which greatly decreases the shelf life of the food. Always place food that is freeze dried in freezer bags in a freezer unless absolutely certain they are 100 per cent sealed.