Contributors: Alex Garcia-Putnam
Through low pressure and freezing temperatures, sublimation can occur, dehydrating or removing the water from an object.
Synonyms in English
Freeze-drying allows the water to be removed from an object in a controlled way. This is critical in the conservation of waterlogged artifacts, such as those from maritime environments. Freeze-drying can be done by simply freezing the object at a low temperature which allows natural sublimation to occur, or in a more aggressive treatment such as vacuum freeze-drying, where the drying takes place in a vacuum (CCI 2013).
Wooden artifacts respond well to freeze-drying, as do metals and other artifactual materials. Bone however should never been freeze-dried, as it will degrade rapidly under such conditions (CCI 2013).
CCI. 2013. Vacuum Freeze-Drying Archaeological Artifacts. http://www.cci-icc.gc.ca/publications/notes/4-2-eng.aspx