Researchers studying thousands of fish bones excavated from a 9,200-year-old pit in Sweden have uncovered the world’s earliest evidence of food fermentation – and it’s accomplished without the use of salt. Modern methods of food fermentation typically require salt and enzymes to prevent spoilage and the growth of potentially harmful microbes. This ancient example of large-scale food storage, described in the Journal of Archaeological Science earlier this month, suggests Early Mesolithic Scandinavian societies were far more complex than researchers previously assumed.
People living in Europe during the Mesolithic period, which spanned 10,000 to 5,000 BC, hadn’t started farming yet, and researchers believed that foraging groups relying on fish and other prey moved around frequently to follow their food sources. In modern and historical circumpolar societies that rely on fish for sustenance (such as those living in Kamchatka), short fishing seasons and large catches meant that drying and smoking all the fish for that winter season wouldn’t be enough – most of the fish was conserved through fermentation in stone- and earth-covered holes in the ground. The lack of artifacts for this sort of long-term, large-scale storage in the Mesolithic was seen as evidence for mobile and less complex societies. But it turns out, Early Mesolithic foragers settled into a semi-sedentary life – and developed technological culture – a lot earlier than we thought.
A total of 10,153 fish bones were found in and around an elongated pit surrounded by postholes and stakeholes – a previously unknown gutter-like structure (pictured to the right) – during an excavation at Norje Sunnansund, an Early Mesolithic settlement site on the southeastern coast of Sweden along the shores of the ancient Lake Vesan. The site had been dated to between 9,600 and 8,600 years old, and it’s the earliest known year-round settlement in southern Scandinavia.
After analyzing the preserved fish bones sieved from the gutter-shaped pit, Lund University’s Adam Boethius revealed that they were freshwater fish that had been fermented. Instead of using salt, they likely acidified the fish first (with pine bark or seal fat, for example) and then wrapped it all up in airtight seal or boar skins before burying it in a pit covered with mud for a few months. The cold was key too.
Around 80 percent of the fish in the pit were the common roach (Rutilus rutilus, pictured above), while perch (Perca fluviatilis) and pike (Esox lucius) were abundant elsewhere within the settlement. Roach is a small boney fish that’s hard to consume, so some form of processing to soften the bones would also make the bones either more edible or removable. There was enough preserved fish to support a large community. Being able to save fish for later meant they could delay their return to foraging – and they managed to do this thousands of years prior to the arrival of farming.
The earliest evidence of fermentation comes from wine-making some 7,400 years ago, and until now, the first evidence of food fermentation was from Egypt about 6,000 years ago.
Image in the text: The gutter after half of it had been removed. Notice the stark contrast with the surrounding clay under the gutter as well as between the stakeholes and the surrounding clay. SHMM