Freeze Dried vs. Dehydrated Foods
Freeze dried and dehydrated foods have a lot in common. Though these preservations methods go about it in a different way, the goal in both cases is to get the water out. Natural foods such as vegetables, beans, and fruits will store safely for a much longer time once the water is removed. When they are rehydrated, freeze dried foods and dehydrated foods are just as delicious, and almost as nutritious as fresh. In fact, both the freeze drying and air drying processes preserve more nutrition than canning. So now that we’ve covered the similarities, what is the difference between freeze dried food and dehydrated food?
Dehydration is one of the oldest methods of preserving food. Our earliest ancestors used the sun and air to dry out food for storage. Today, we use a slow air drying process that preserves flavor and nutrients. As the moisture is drawn out, the cells change shape and get smaller. That is why dehydrated foods take a bit longer to rehydrate than freeze dried foods. But, because dehydrated food shrinks, you can store more of it in less space. One cup of our dried peppers will rehydrate to a two and a half cups. One cup of our dehydrated black beans will rehydrate to two cups. Add those to your cook pot and you can feed a whole family (or one hungry backpacker).
Freeze Dried Food
It is thought that the Incas of the Andes were the first people to freeze dry food. They preserved food using an ingenious method that took advantage of the temperature extremes that can be found at their high altitude home. Incan cooks would leave foods such as potatoes and meat outside to freeze overnight. The next day the heat of the sun would quickly evaporate the water. Voila! At the end of the process they would have a supply of chuño, a freeze-dried potato pulp, and charqui, or freeze dried beef. Fun fact: If ch’arki sounds familiar, that is because this word is the Quechua language ancestor of the English word jerky.
Today, the freeze drying process typically involves a special vacuum cabinet that vaporizes the water in frozen foods and vacuums it out before it can become a liquid. That process is called "sublimation." Unlike the dehydration process, freeze drying does not change the shape of a plant’s cells. That is why freeze dried vegetables look more like their fresh counterparts and why they rehydrate so fast. One cup of freeze dried fruit and berries rehydrates to only one cup. But they are so tasty freeze dried, that you don’t even have to rehydrate them—just pop them in your mouth for a healthy, all natural snack.