The difference between freeze dried and dehydrated can sometimes be hard to grasp. I was introduced to freeze dried foods in 2010, and I became so excited by what I had learned about the advantages of having and using freeze dried foods that I started sharing my new found love with others. I noticed that even after I explain the difference between freeze dried and dehydrated, it was still hard for some of my friends to understand. The concept of freeze drying is so new to many, and they just didn’t know what to make of it. But the differences are actually huge, when they got it and realized they were excited and eager to use it.
So what does “freeze dried” actually mean. Simply put, freeze drying is just removing the water from a piece of food, using cold instead of heat, as dehydration would use. This is done by placing the already flash frozen food into a freeze drying unit, then slightly raising the temperature (to a nice warm negative 50 degrees) while dropping the air pressure to sublimate the water (turning the ice into water vapor). The water vapor is then vacuum extracted, causing no damage to the cell structure of the food while retaining almost all of the nutrients. This process also makes the food incredibly shelf stable and, unlike dehydrated foods, allows them to keep the food simple and clean with no added artificial flavors, colors, or preservatives.
The process for dehydrating foods is heating the food until the water is removed by evaporation. It is not possible to remove as much water through dehydration as it is for freeze drying. Dehydration, depending on the process used, leaves about 5% to 30% of the water in the food, whereas freeze drying leaves about 1%-2%.
This difference matters as it significantly affects shelf life. The typical shelf life of freeze dried foods is 20 to 30 years. The typical shelf life of dehydrated foods is 1 to 8 years. The average opened shelf life of Thrive Foods is 1 year, being stored properly.
Since freeze drying removes so much water, no additives are needed for single ingredient items. Thrive Life pineapple is just pineapple, even the enzymes are kept intact. No need for additives. Dehydrated pineapple turns brown, to stop that browning sulfur is added. To mask the taste of the sulfur, sugar is added. Salt, sugar, or other additives are often added to dehydrated foods to maintain their shelf life.
Freeze drying retains 98% of nutrients. With dehydration, up to 50% of nutrients are lost due to the process. Heat destroys some of the nutrients and some of the cell structure of the food. The difference is really easy to see when you know you dehydrate Grapes to end up with Raisins. Since Thrive freeze dried produce are vine ripened and then flash frozen within hours they contain even more nutrients than artificially ripened produce.