First, we put the food on a tray and put it inside the freeze dryer. The machine makes the food very cold, colder than your freezer at home. The water in the food turns into ice, like when you make popsicles.
Next, the machine takes out all the air from inside. This makes the ice turn into a gas, like when you see steam coming out of a kettle. The gas leaves the food and goes out of the machine.
Finally, the machine warms up the food a little bit, but not too much. This makes sure that there is no water left in the food at all. The food is now freeze-dried and ready to be stored.
