The cost of a freeze dryer isn’t cheap. We bought ours from Harvest Right on a sale that included shipping, a filtration unit for the vacuum pump oil, mylar bags and a sealer.
The process is simple, our fresh untreated fruit and vegetables are cleaned and sliced into bite size pieces and put on stainless steel trays. The dryer freezes the food to -40 degrees Fahrenheit for roughly nine hours. Once the food is frozen, the freeze dryer creates at powerful vacuum around the food. Then as the food is slightly warmed, the ice transitions into vapor and is drawn out of the food and collects as clear ice on the cold chamber. The warm/freeze cycle is repeated several times until all of the water has been removed from the food.
Having folks sample freeze dried product at the market has been interesting. Most expect a conventional hot air dried product (somewhat leathery) and are surprised with the taste intensity and how the product is 'as light as a feather'. I’ve seen some pretty wide eyes when describing the thirty hour process and the fact that the water is crystal clear when the unit is defrosted.
We freeze dry what we grow (and what tastes good freeze dried as a snack or is more viable to be used in a reconstituted manner) for market. Strawberries, apricots, peaches, tomatoes, squash and alibi cucumbers have had great reviews. Our ripe apples will come to the market in a freeze dried fashion as well.
The picture is our first batch which took 30 hours and was complete around 3 in the morning. We were like kids on Christmas trying apricots, berries, plums and peaches!