The mummification process itself was likely a combination of freeze-drying and cold storage. The initial rapid freezing halted bacterial decomposition. As the body was buried under compressing snow and ice, the remaining moisture was gradually extracted, completing the desiccation process. The result is different from an embalmed mummy: Ötzi’s tissues are dried and contracted rather than chemically preserved, and the outer epidermis (the surface skin layer) is absent — it separated from the underlying dermis during the mummification process, which is normal for this type of preservation.
The 2022 study by Lars Pilø and colleagues in the journal *The Holocene* addressed an earlier debate about whether Ötzi’s preservation site represented a continuous cold environment or a glacial margin that might have experienced thaw-refreeze cycles. The study’s analysis of the site’s geomorphology and of the state of the organic materials found with the body concluded that the site had experienced multiple thaw-refreeze cycles — that the body and its associated objects had been partially or fully exposed on the glacier surface more than once before the final exposure in 1991.
This conclusion was significant because it resolved a puzzle in the archaeological record: some of the organic materials found near the body were separated from it, and their condition suggested repeated wetting and drying. Rather than indicating disturbance of the site by humans or animals, the evidence pointed to natural glacial processes that had redistributed some materials. This is important for interpreting the association between the body and the objects — not everything found near Ötzi was necessarily with him when he died; some objects may have been deposited before or after his body reached its final resting place.