Amid the wreckage of a 17th century ship off the southeast coast of Sweden, divers believe they have found a 340-year-old cheese. “We’re pretty sure it’s some kind of dairy product, butter or cheese,” leader of the diving expedition Lars Einarsson told local media, according to the Guardian. “It’s like a mixture of yeast and Roquefort, a sort of really ripe, unpasteurized cheese.” The explorers found the “mass of bacteria” in a tin pressed into the clay of a seabed, but when it was brought to the surface, the drop in pressure allowed its contents (and smell) to leak out. “I certainly don’t recommend tasting it,” Einarsson said. Known as the Kronan, the battleship — one of the largest ships in the world at the time — sank in 1676 during a battle against a Danish-Dutch fleet.