Freeze-drying takes moisture out of pet food but in a different way than dehydration or extrusion. The process of freeze-drying involves flash freezing the dog food and then putting into a reduced-pressure system where the water sublimates changing from solid to gas. Then the temperature is raised higher than in the first step and can even be slightly above 0 degrees C to break the water molecules from the dog food.

This preserves the enzymes, vitamins and nutrients in the pet food and you can call the food raw because of this process.