Backpacking Food - Version 1.0 Learn which food makes the best backpacking food. Dehydrated or freeze dried food. In this article we will explore the pros and cons of dehydrated and freeze dried food for use as a source of backpacking food.Dehydrated food is usually heated up to130F to 145F in a food dehydrator to remove water from the food. This process results in a reduction in size, increase in toughness and a reduction in weight caused by water loss. Freeze drying on the other hand flash freezes the food to -40F and then uses a vacuum to evaporate the ice which results in very little change in volume and a loss of up to 98% of its water content. The lack of water and reduction of oxygen in the packaged food creates a product with a very long shelf life. In some cases the shelf life can be as long as 25 years which is ideal for long term food storage.