Recently, Jack Conway was “cutting turf,” the term for digging up blocks of moss in Emlagh peat bog in County Meath, Ireland, when he discovered a 22-pound lump of ʙuттer. The find, believed to be 2,000 years old, according to the Irish Times, isn’t an unusual occurrence in Ireland, where every year, people digging up peat moss to heat their homes encounter chunks of the dairy.

The discoveries, which are called Bog ʙuттer, can be thousands of years old. In 2009, a 77-pound, 3,000-year-old oak barrel of the stuff was found in County Kildare. In 2013, a turf cutter in County Offaly found a 100-pound, 5,000-year-old chunk. Many examples of the ʙuттer are found in Irish museums, including the place dedicated to the golden spread, Cork’s ʙuттer Museum.

So what is Bog ʙuттer? It’s exactly what it sounds like—ʙuттer made from cow’s milk, buried in a bog. What makes it special is its age. After spending so much time in the cool, damp peat, it starts to take on the appearance and consistency of paraffin wax. According to a study on bog ʙuттer by researchers from the University of Bristol, some of the chunks are non-dairy. When analyzing carbon isotopes in nine samples of the ʙuттer, they found that six of them were indeed dairy products, while the other three were from animals, perhaps tallow (rendered fat) stored for later use.

In a paper published in the Journal of Irish Archaeology, Caroline Earwood explains that bog ʙuттer is usually found in earthenware pots, wooden containers, animal skins, or wrapped in bark and takes on a pungent, cheesy odor. Looking at over 274 instances of bog ʙuттer from the Iron Age to medieval times, Earwood concluded that early Celtic people probably sunk the ʙuттer in the bog simply to preserve it or protect from thieves. The cool, low-oxygen, high acid environment of the bog made a perfect natural refrigerator. Seeing as ʙuттer was a valuable commodity and was used to pay taxes, saving it for times of drought, famine, or war would have been a good idea.

There are other theories about the ʙuттer as well. It could also have been buried in the bog as an offering to the gods or spirits, the Irish Times notes. The Bristol researchers wonder whether burying the ʙuттer in the peat was a type of food processing that changed the chemical composition of the ʙuттer to make it tastier.

Savina Donohoe, Curator of Cavan County Museum, which accepted Conway’s ʙuттer lump before sending it to the National Museum of Ireland for analysis, tells UTV Ireland the Conway’s big pat is thought to be thousands of years old, but that won’t be confirmed until researchers test the twigs and bark stuck to the ʙuттerball. Donohoe, who handled the stuff, said it smelled familiar.

“It did smell like ʙuттer, after I had held it in my hands, my hands really did smell of ʙuттer. There was even a smell of ʙuттer in the room it was in,” Donohoe says.

Though Irish celebrity chef Kevin Thornton took a bite of bog ʙuттer in 2014, Andy Halpin, ᴀssistant keeper at the National Museum’s Irish Antiquities Division, advises the Irish Times that it’s probably not wise to sample the Iron Age delicacy.

For those curious, Ben Reade, head of Culinary Research and Development at Nordic Food Lab created his own ancient ʙuттer recipe back in 2012. Reade’s guinea pigs had mixed things to say about the taste. “The organoleptic [sensory] qualities of this product were to many surprising, causing disgust in some and enjoyment in others,” he writes. “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’.”