A freeze dryer, also known as lyophilize, is a machine used to remove moisture from perishable materials while preserving their structure and integrity. It works by freezing the material and then subjecting it to a vacuum, which causes the frozen water within the material to sublimate directly from solid to cloud, bypassing the liquid phase. This process helps to retain the original shape, texture, and nutritional content of the material while extending its shelf life. Freeze dryers are commonly used in food preservation, pharmaceuticals, biological research, and other industries where maintaining product quality is crucial.