Grave Wax Clings to a Skull, via True Forensics
Grave wax is a wax-like organic substance that appears as crumbly and waxy material consisting mostly of saturated fatty acids that appears in certain graves. The color of the wax depends on the color of the body fat; white or brown body fat produces adipocere that is grayish white or tan. The substance is also known as corpse or mortuary wax, and scientifically is called adipocere. The transformation of fats into adipocere occurs best in the absence of oxygen in a cold and humid environment, such as in wet ground or mud at the bottom of a lake or a sealed casket, and it can occur with both embalmed and untreated bodies. It was described by Sir Thomas Browne in his discourse Hydriotaphia, Urn Burial (1658):
In a Hydropicall body ten years buried in a Church-yard, we met with a fat concretion, where the nitre of the Earth, and the salt and lixivious liquor of the body, had coagulated large lumps of fat, into the consistence of the hardest castile-soap: wherof part remaineth with us.
The process can also lead to the entire body turning into adipocere under certain moist and anaerobic bacterial conditions, known as saponification. Saponification is defined as the conversion of fatty acids into soap through hydrolysis with alcohol creating glycerol.
In 1875 , two soap mummies were discovered in Philadelphia. Both individuals had reportedly died of Yellow Fever in 1792 and were 60 year olds from the family Ellenbogen. However further research into the individuals in 1987 revealed that Yellow Fever was not present during that time period, nor were any death records found for individuals named Ellenbogen. Radiographic analysis of the female body revealed shroud pins embedded within the soap that date to 1824. The soap lady, based on these radiographs was determined to be less than 40 years old. Radiographs were finally taken of the soap man in 1994, revealing he was approximately 40 to 50 years old, and also buried no earlier than 1824 due to the presence of shroud pins created in that year. The dating is further supported by the presence of his knee high socks- amazingly preserved. Radiographic comparison between the two individuals showed that the saponification didn’t occur the same in both: the soap man retained his internal organs while the soap lady was hydrolyzed all the way through.
Swedish Soap Corpse found in 2011, via Live Science
In Sweden in 2011, a 300 year old headless corpse was found floating in the river. At first it was thought to be a fairly recent death by the presence of blue and white fleshy material, but further examination revealed that this was the preserved adipocere. The ‘soap’ around the body, while preserving many of the soft organs, does obscure the actual identification of age, sex and pathology. Radiology was needed for the analysis of the Philadelphia mummies, but in this Swedish case they simply removed portions of the wax to reveal the pelvic bones. This showed that the body belonged to a adult male. The wax preserved the heart, which had turned blue due to minerals in the ground, and the intestines, which contained cherry pits.
Whether its called grave wax or adipocere, the process can preserve portions of the deceased and is found in the graves. It does take a number of weeks, and often months for this process to work, and the conditions must be perfect for it. It occurs more often than thought, but often only leads to small amounts of preserved fatty tissue, rather than the full body turning into a soap-like substance.