By Harold McGee
Freeze-drying is the technique originally used by Andean peoples to make charqui; they took advantage of the thin dry air to evaporate moisture from meat during sunny days and sublimate it from ice crystals during freezing nights. The result was an uncooked, honeycombed tissue that would readily reabsorb water during later cooking. In the industrial version, the meat is rapidly frozen under vacuum, then mildly heated to sublimate its water. Because this kind of desiccation doesn’t cause cooking and compaction of the tissue, relatively thick pieces can be dried and reconstituted.