Freeze Drying of Food ProductsAn accessible guide to safely dehydrating food Freeze drying, or lyophilization, is a method for dehydrating food or other substances through the use of pressure instead of heat. This allows for the preservation and storage of high value food products without altering their essential properties or causing a reduction in quality or value. For these reasons, freeze drying is the most reliable method for preserving and distributing high quality products.