That's a great question that we are asked often! So often that we've dedicated an entire blog post about it, which you can read about here. In short, dehydration in its most basic form is heat and airflow. Products are placed on trays where warm air is circulated throughout the dehydrator to slowly dry out the food and usually removes between 90 to 95% of water. Freeze-drying is a more complicated process as it involves freezing all food to a very low temperature, usually between -30C and - 40C; after this a vacuum is pulled and then the temperature within the machine is slowly heated up so that the moisture transitions directly from ice to water vapor without ever becoming a liquid. This process is known as submlimation.