Understanding beeswax

By Tuuli Kasso, PhD in Science Fellow at the Natural History Museum of Denmark, University of Copenhagen. Tuuli is a visiting researcher, who has used the Museum’s collection to help her understanding of beeswax. 

When working on the dissertation for my MSc in Archaeological Science last year, I explored the medieval craftsmanship of sealing wax. I was interested in the way the medieval wax seals had flaked, as the beeswax dried out. Drawing on my previous education in conservation techniques, I began a close investigation of the prestigious material, beeswax.

Although some of the ingredients of sealing wax are very hazardous, there is nothing dangerous in beeswax… except the bees! Produced by honey bees, Apis mellifera, honey and beeswax were important commodities in the Middle Ages. Beekeeping was a skilful profession, housing colonies in woven hives, known as skeps. Colonies were carefully selected to overwinter for the next season.

Beeswax was also important in the Middle Ages for lighting, and beeswax candles were preferred for their pleasant smell. After the Protestant Reformation in the 16th and 17th centuries, the religious use of candles decreased, so demand for beeswax declined.

On my quest to understand the degradation of beeswax in sealing wax and write my disseration, I was very lucky to use some samples from the entomological collections from the Oxford University Museum of Natural History. After some early mornings spent amongst the Westwood collection, I found the perfect specimens of natural honeycombs, from the 19th century. The old hand-written labels were also a lovely encounter when exploring the historical collections.

I compared the samples to modern beeswax and medieval seal samples, and learned that the degradation of beeswax is caused by multiple factors, triggered also by storage conditions. The composition of beeswax is very complex, and there are differences caused by the age of the bee in addition to geographical provenance.

The recent catastrophic decline of bee populations has drawn focus to save the bees, and in my PhD research (University of Copenhagen and University of Cambridge) I will explore the recovery of ancient DNA and proteins of bees from beeswax, to cast light on the health of bee populations over time.