Freeze drying, also known as freeze drying, is a form of drying that is accomplished by freezing a wet substance and allowing the ice to sublimate directly into vapor in l 'exposing to a low pressure quantity. of water vapor. This drying method is carried out in a special type of vacuum designed for this method. Freeze drying is used in many cases, often as a way to preserve the material or reduce its weight; thus allowing the transport of certain substances to become less difficult. Freeze drying has been around and been successful for a long time. The freeze-drying method was first observed in ancient Indian tribes. The Peruvian Incas were pretty much the first to use this clever method. They did this by leaving their food out and letting it set in cold weather and freeze. Then the Incas would trample their food to remove any remaining water. They then left their crushed food in the sun to dry it. Freeze drying was later observed during World War II. This method was, however, used in a slightly different way than the Incas. Military crews of World War II used ...