Grain starches extracted from an ancient grinding stone in Israel reveal that humans milled wild barley and wheat 22,000 years ago, according to two archaeologists. The finding represents the oldest known evidence of processed food and may help explain how early humans transitioned from being hunter-gatherers to settled farmers.
In the Middle East, archaeological evidence documents grain agriculture as far back as 12,000 years ago. Until now, however, there was little in the archaeological record to help researchers understand the steps leading to agriculture and dependence on cultivated foods. For example, no one knew when and how humans began processing and cooking wild cereal grains. Now, an ancient campsite on the southwestern shore of the Sea of Galilee in Israel has provided some answers.
In the 5 August issue of Nature, Harvard University paleoarchaeologist Ehud Weiss and archaeobotanist Dolores Piperno of the Smithsonian Tropical Research Institute in Falls Church, Virginia, describe 34 different species of wild grass seed collected at the Israeli site Ohalo II. The seeds were preserved thanks to centuries of anaerobic conditions--the Upper Paleolithic site was buried in silt until 1989. The researchers were especially interested in seeds nestled in the cracks of a grinding stone found at the site. By measuring how much starch the seeds contained--a technique commonly used by botanists to identify seeds--they found that only two of the 34 species of grass were on the grinding stone: wild barley and wheat. That makes sense, Piperno says, because unlike other wild grasses, both wheat and barley have to be pounded or ground to remove the fibrous outer hull to achieve maximum nutritional benefit.Extensive carbon-14 dating of the site places occupation at 23,500 to 22,500 years ago, more than 10,000 years before wheat and barley were domesticated in the region. The Ohalo II artifacts, therefore, provide intriguing insight into preagricultural lifestyles, the team says. Not only did people at the site apparently mill grain, but a simple hearth oven suggests that they may even have baked dough made from the flour."Grain starches from [this] 'Ice Age food processor' confirm that people were using species that later became cultivated crops," says paleoecologist Mark Bush of the Florida Institute of Technology in Melbourne. The finding is "clearly a breakthrough" in establishing a time frame for wild grain processing, says archaeologist Naama Goren-Inbar of the Hebrew University of Jerusalem in Israel, and as such, it's a "wonderful contribution to our understanding of human behavior."