Conway is a turf cutter, meaning he harvests “turf” or peat — it’s a type of moss — from a bog to burn for warmth during the winter. He was chopping turf at the bog when he came across a 22-pound chunk of butter, the Irish Times reported. Researchers at the Cavan Museum estimated it to be more than 2,000 years old.
Bog butter is just that: butter made from cow’s milk that’s been buried in a bog, though, after thousands of years, it often has the consistency of cheese.
It’s actually not that uncommon of a find for turf cutters in Ireland, either. As Smithsonian magazine noted, a 3,000-year-old, three-foot-wide barrel stuffed with 77 pounds of bog butter was found in 2009. Even more shocking, turf cutters found a 5,000-year-old wooden keg containing 100 pounds of the butter in 2013.
People have actually been stumbling upon bog butter for at least two centuries. In the 1892 edition of the Journal of the Royal Society of Antiquaries of Ireland, the Rev. James O’Laverty recounts finding a lump that “still retains the marks of the hand and fingers of the ancient dame who pressed it into its present shape” and that “tastes somewhat like cheese.”
In her article “Bog Butter: A Two Thousand Year History” in the Journal of Irish Archaeology, Caroline Earwood wrote: “It is usually found as a whitish, solid mass of fatty material with a distinctive, pungent and slightly offensive smell. It is found either as a lump, or in containers which are most often made of wood but include baskets and skins.”
The earliest discoveries of bog butter date to the Iron Age, but she wrote that it may have existed earlier.
No one is sure exactly why the butter was buried in bogs — some think it was sometimes an offering to the gods — but evidence strongly suggests it was a method of preservation.
Most bog butter doesn’t contain salt, which was often used as a means of preserving food before modern refrigeration. The bogs, which are essentially cold-water swamps, and their native peat do a fine job of keeping food fresh. A University of Michigan researcher found that meat left in a bog for two years was just as preserved as meat kept in his freezer, the University Record reported in 1995.
Peat is compressed plant matter, which Nature reported is both cool and contains little oxygen while remaining highly acidic, allowing it to act as a sort of refrigerator. It seems to work — Savina Donohoe, curator of Cavan County Museum who sent Conway’s butter lump to the National Museum of Ireland, said it smelled just like, well, butter.
“It did smell like butter. After I had held it in my hands, my hands really did smell of butter,” Donohoe told UTV Ireland. “There was even a smell of butter in the room it was in.”
In fact, peat bogs are such wonderful environments for preserving organic matter, they’ve been known to almost perfectly mummify corpses.
Hundreds of “bog bodies” have been found during the past two centuries, according to the USA Today. The oldest one unearthed is a preserved skeleton called the Koelbjerg Woman, which dates to about 8000 B.C.
Other bodies, though, retain their skin and internal organs. The Tollund Man, for example, still had his leathery skin intact when he was found in the Bjaeldskovdal bog in Denmark and is considered by some to be the most well preserved body ever found from prehistoric times. He was so well preserved that the men who found him thought they had stumbled on a modern murder scene, PBS reported. He was actually about 2,400 years old.
Given that level of preservation, most of the butter is edible. Irish celebrity chef Kevin Thornton, who owns the Michelin-starred Thornton’s Restaurant in Dublin, claimed to have tasted a 4,000-year-old sample of bog butter.
“I was really excited about it. We tasted it,” he told the Irish Independent in 2014. “There’s fermentation but it’s not fermentation because it’s gone way beyond that. Then you get this taste coming down or right up through your nose.”
Andy Halpin, assistant keeper in the Cavan Museum’s Irish antiquities division, said one could probably eat the butter, though he’s not sure why one would.
“Theoretically the stuff is still edible, but we wouldn’t say it’s advisable,” Halpin told the Irish Times.
Curious what it might taste like, Ben Reade, head of culinary research and development at Nordic Food Lab created his own bog butter, albeit one aged for a bit less time than the aforementioned.
Echoing the lines from James Farewell’s 1689 poem “The Irish Hudibras” — “butter to eat with their hog, was seven years buried in a bog” — they buried one large birch barrel of butter in the ground, where it will remain for seven years. The other remained in the ground for only three months, before it was tasted at the Nordic Food Lab in Copenhagen and at the Oxford Symposium on Food and Cookery in 2012, in Britain.
In its time underground the butter did not go rancid, as one would expect butter of the same quality to do in a fridge over the same time. The organoleptic qualities of this product were too many surprising, causing disgust in some and enjoyment in others. The fat absorbs a considerable amount of flavor from its surroundings, gaining flavor notes which were described primarily as “animal” or “gamey,” “moss,” “funky,” “pungent,” and “salami.” These characteristics are certainly far-flung from the creamy acidity of a freshly made cultured butter, but have been found useful in the kitchen especially with strong and pungent dishes, in a similar manner to aged ghee.
Even so, if you happen to find a lump of butter buried in the back yard, it may be best to forgo it for the store-bought variety.