One of the most effective methods of removing moisture from food to keep it fresh tasting and to give it a long shelf life is freeze drying. Freeze-dried foods can last up to 10 years if properly sealed. Some additional benefits of freeze drying are: (1) It removes 98 percent of moisture from the prepared food; (2) it does not employ heat, which keeps the tissue, taste and smell of food intact; (3) freeze-dried foods are lightweight and compact; and (4) freeze-dried foods remarkably retain the nutrition, flavor and aroma of the food being prepared.
Drawbacks include time and cost: It can take days to properly freeze dry foods, and it requires large pieces of expensive equipment. Most people cannot do it on their own or in their own homes.
Food dehydration is an affordable, easy do-it-yourself food preservation method you can perform in your own home. To dehydrate foods, you heat them in a dehydrator or dehydrating oven. Moisture is removed by evaporation, drying the food and reducing its weight. Some benefits to dehydration include shelf life--dehydrated foods can last up to 5 years if stored in a cool, dry place--and removal of 98 percent of moisture content from food, giving you lightweight, easy-to-carry food. Dehydration reduces the weight of some foods, especially fruits and vegetables, by more than two thirds of their original weight.
Drawbacks include slight changes in texture and flavor: Dehydrating employs heat to remove moisture, which can cause the food being prepared to shrink and toughen. When you are on the trail, anything tastes good, so flavor isn't too much of an issue. Dehydrated foods do, however, have slightly altered flavors from the breakdown of tissue caused by the heated dehydration process.
Which is Better?
Ranked in terms of convenience and cost-effectiveness, dehydration is clearly the better option. For overnight, week-long or extended camping or backcountry hiking trips, you can save money and do it yourself when you use a food dehydrator.
While freeze-drying food can last up to 10 years, few campers have the need to store their food for such long periods of time. Given the amount of expensive equipment needed for freeze drying, dehydrating is a much easier and cheaper option that still gives you satisfying and nutritious food.