After over two decades of recovering cannons, gold coins, and jewelry from a 340-year-old Swedish shipwreck, marine archaeologists can now add a chunk of cheese to their list of finds.

While exploring the wreckage of the 17th century Swedish royal vessel Kronan, Kalmar Museum researcher Lars Einarsson noticed a small, tin jar buried in the mud at the bottom of the shipwreck. When he brought it to the surface, the decrease in pressure caused some of the contents to ooze out of the container.

“That’s when the smell hit us,” Einarsson told local media. “It’s a pretty good guess that it’s some kind of dairy product, and we think it is cheese.”

The fetid find was revealed on Wednesday along with several other discoveries from the expedition, including a diamond ring and a handful of gold coins.

The Kronan — a Swedish warship that was one of the largest in the world when it set sail in 1668 — was 53 metres long and was equipped with 110 large cannons. It sank off the coast of Ӧland in eastern Sweden in 1676, during a battle with the Danish-Dutch fleet. Historians believe that the ship capsized after making a sharp turn in bad weather, somehow causing a gunpowder explosion near the bow. Out of the roughly 850 people on board, only 42 survived.

The wreckage was discovered in 1980 and is still the largest marine archaeology site in Sweden. More than 30,000 artifacts have been found in the shipwreck, including a hoard of textiles that have given historians insights into how clothes were made in the late 1600s. During an expedition in 1997, divers discovered one of the world’s oldest violins, which likely belonged to one of the ship’s officers.

The latest, smelly find might say something about 17th century tastes, though despite what people often say about cheese and age, Einarsson has his doubts.

“It’s been in the mud, so it’s reasonably well preserved, but at the same time it has been at the bottom of the sea for 340 years,” he said. “I certainly don’t recommend tasting it.”

I think it smells quite nice, because I like exotic food

He described the smell of the substance as a mixture of yeast and Roquefort.

With nearly 90 per cent of the excavation completed, divers will continue to explore the Kronan for three more years. After that, Einarsson hopes that there will be a museum focused on the shipwreck.

For now, the cheese is being kept refrigerated to keep it from decomposing completely. Researchers hope to analyze the gooey substance to determine what its made from.

“I think it smells quite nice, because I like exotic food,” Einarsson added. “But I wouldn’t want to taste it.”