Interesting. Sometime I may try vacuum-sealing a small amount of veggies in a Mason jar, then placing the jar into the freezer to see if water vapor crystals form inside the jar. Dumping the veggies into another dry jar and repeating may eventually give me "freeze-dried" veggies. This would be time-consuming and take up freezer space, as you mentioned. I can only see doing this with something like peas that don't rehydrate easily. it would be far easier to buy dehydrated peas or do as I've been, which is to break up dehydrated peas in a blender of food processor.