Freeze-dried coffee is the most successfully marketed freeze-dried product.
Freeze-drying, the method of nearly completely removing moisture from material, was initially used as a way to preserve blood plasma during World War II. It wasn't long before scientists realized that this technology, which allowed materials to maintain their basic structure while remaining contamination free, could be used to store and transport consumer food products cheaply and efficiently. For the most part, freeze-dried food retains its original color, flavor, texture and nutrients when reconstituted with water; making it an attractive method of preservation. It is possible to freeze-dry foods yourself, but to do so it's necessary to purchase a freeze-drying machine, which is expensive.
Instructions
1. Check the quality of the food and make sure it hasn't been contaminated in any way. Pay special attention to food susceptible to spoilage, like fruits and meats.
2. Prepare the food to be freeze-dried. Cut, pit and peel vegetables and fruits. Cook and cut seafood and meats into smaller pieces. Place all the food in the freezer and freeze completely.
3. Ready the freeze-drying machine. Clean and dry the chamber. Switch the machine on and wait until it reaches the appropriate vacuum level; in most machines an LED light indicates this level.
4. Place food inside the machine according to instruction. Some machines require solid food be laid out on metal trays and liquid be placed into shallow metal pans. Other machines require food be placed in desiccators or flasks. Always make sure the machine returns to the appropriate vacuum level before adding additional food.
5. Allow the freeze-drying machine to run the full cycle; this is usually a 24-hour period, but varies from machine to machine.
6. Store the freeze-dried food in an airtight bag. Press out all of the air beforehand if using plastic resealable bags.
Tags: freeze-drying machine, appropriate vacuum, appropriate vacuum level, freeze-dried food, machines require
