Ancient inhabitants of what is now Ireland and Scotland buried baskets of the so-called "marsh butter" in bogs, presumably to avoid deterioration. Thanks to the unique chemistry of these bogs, the crates have survived for thousands of years. Now, scientists at University College Dublin have conducted chemical analyzes and radiocarbon dating of numerous marsh butters recovered from archaeological sites in Ireland. They found that the practice was a remarkably long-standing tradition, covering at least 3,500 years, according to their new article in Nature: Scientific Reports .
The researchers also discovered the first conclusive evidence that the Irish bog the butters derive from milk fat instead of meat. According to bioarchaeologist Kristina Killgrove, who writes in Forbes "Previous attempts at analysis of marsh butter have failed, because although butter is known to have an animal origin, the techniques were not able to distinguish between adipose tissue where lipids or fats are stored and milk fats from ruminants such as cows and sheep, particularly over an archaeological time depth. "
There are about 430 recorded stash of marsh butter, according to Benjamin Reade from the Nordic Food Lab, 274 of which have been found in Scotland and Ireland. It is usually found wrapped in some kind of wooden containers, barrels, barrels, etc. Or animal blisters. Marsh butter may have been buried as a means of preserving meat, based on a 1995 study that showed that meat buried in peat bogs for up to two years had approximately the same levels of bacteria and pathogens as meat stored in a modern freezer. Alternatively, it may have been a kind of primitive food treatment.
The Dublin researchers compared their analyzes of stable carbon isotopes (targeting fatty acids in swamp butter samples) in a modern global database of animal fat. They found that 26 of their 32 samples were made permanently from dairy products, and three others were most likely made from dairy products. Their analysis of the last three samples was inconclusive. Furthermore, radiocarbon dating of the samples showed that they dated back to the Bronze Age (circa 1700 BC).
And yes, there have been modern experiments to produce marsh butter, especially samples presented at the 2012 Oxford Symposium on Food and Cooking. Reade led the project and was pleased to find that his homemade marsh butter did not become rancid during his three months underground. (A second escort was left to age for seven years.) However, the result was something of an acquired taste, "which causes disgust in some and enjoyment in others," he wrote. "The fat absorbs a considerable amount of flavor from the surrounding environment, obtaining aromatic notes which have been described mainly as" animals "," wild "," mossy "," funky "," pungent "and" salami ".  But Reade thinks that the taste profile would work well in "strong and pungent dishes [contemporary] similar to the aged ghee." In fact, there is a North African version of marsh butter called smen (it is similar) with clarified butter, or clarified butter) which is still used today, considered a delicacy on a par with fine cheeses
DOI: Scientific Reports 2019. 10.1038 / s41598-019-40975-y (information on DOIs).