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20190325 - Bog Butter Research

New study pushes Irish bog butter back into Early Bronze Age

A new study by (opens in a new window)Dr Jessica Smyth, with colleagues from the University of Bristol, the National Museum of Ireland, Queen’s University Belfast and UCC, has revealed the deposition of butter in bogs in Ireland dates from at least the Early Bronze Age, much earlier than previously thought.

Bog butters are large white or yellow waxy deposits regularly discovered within the peat bogs of Ireland and Scotland. Often found in wooden containers or wrapped in animal bladders, they are considered to have been buried intentionally by past farming communities. While it is well known that bog butter is some sort of animal fat, compound-specific stable isotope analysis of the fatty acids in the degraded bog butters is the only way to identify the true origins of the fat – whether it was a milk fat like butter, or a carcass fat like tallow or lard. Combining this analysis with radiocarbon dating, the study provides unparalleled insight into an extraordinarily long-lived activity. The team sampled 32 bog butters held in the collections of the National Museum of Ireland, conclusively establishing that Irish bog ‘butter’ is indeed butter and that its use spanned at least 3,500 years, from around 1700 BC to the 17th century AD. Together with two recently dated samples, this study brings to five the number of Bronze Age bog butters recorded from Ireland. Their date is extremely significant and pushes back known depositional activity by as much as 1500 years. Over such a long time span, it is unlikely there was a single reason for the deposition of bog butter: in certain periods they may have been votive deposits, while at other points in time it may have been more about storage and even protection of valuable resources.

The results of the study are published in open access journal Scientific Reports and can be viewed here:

(opens in a new window)https://www.nature.com/articles/s41598-019-40975-y

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