Oldest Flour Ground 32,000 Years Ago

Hunter-gatherers ground oat grains into flour 32,000 years ago in a cave in Italy.

The world's oldest flour was made from oat some 32,000 years ago, according to a new analysis of a Paleolithic stone tool.

Recovered in 1989 from a cave in southeastern Italy called Grotta Paglicci, in a layer dating to the Gravettian period about 32,000 years ago, the pestle-type stone was used by hunter-gatherers who made intensive use of the cave.

They left behind wall paintings of horses and hands, human burials and distinctive artifacts, as shown by previous research carried out by Arturo Palma di Cesnola and Annamaria Ronchitelli of the University of Siena, in collaboration with the Archaeological Superintendency of Puglia.

Photos: What Did Prehistoric Humans Eat?

The elongated cobble of sandstone measures about 5 inches long, it's broken at one end and rounded at the other and features longitudinal fissures on its surface.

"On the basis of the functional analysis, this item has been interpreted as a peste-grinder," Marta Mariotti Lippi, a botany professor at the University of Florence, Anna Revedin, of the Italian Institute of Prehistory and Protohistory in Florence, Biancamaria Aranguren of the Archaeology Superintendency of Tuscany and colleagues wrote in in the Proceedings of the National Academy of Sciences.

They noted the rounded end was used to crush seeds, while the stone's flat surface allowed to grind the broken seeds into flour.

Although it was carefully investigated at the time it came to light, the stone tool was recently subjected to new analysis in order to recover possible bits of starch grain still intact.

The sampling method, adopted for the first time in this research, involved wrapping the stone in a plastic film, to preserve it for further analysis. The researchers exposed only three tiny patches and washed them to recovery loosen debris.

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"Overall, about 1,000 starch grains were observed," the researchers wrote.

They included acorns and relatives of millet, but the most plentiful starch grains were those from wild Avena (oat) species.

Previous starch analysis on grinding stones from Bilancino in the Tuscan Mugello Valley, Kostenki 16 at Pokrovsky Valley, Russia and Pavlov VI in the Czech Republic showed plant exploitation was already spread across Europe during the Mid-Upper Paleolithic.

But the finding at the Grotta Paglicci represents the most ancient evidence of the processing of oat.

Early Human Ancestors Ate Grass

The biologists at the University of Florence recorded a great number of swollen and partly gelatinized grains, featuring the physico-chemical changes that occurs after thermal treatments.

"Grinding oat requires a previous drying of the grains to be processed," Anna Revedin told Discovery News.

"Given a climate colder than the current one, the inhabitants of Grotta Paglicci likely used heating to accelerate drying," Revedin said.

She added that heat treatment of oat helps its preservation while improving the flavor and nutritional properties.

"The early modern humans of Grotta Paglicci already had a knowledge that included a multi-step technology and surprising skills in processing food plants," Revedin said.

The early Gravettian inhabitants of the cave are the most ancient population to use a method that involves at least four steps in preparing plants for consumption.

While the stone tool showed the grains were heated and ground, there is no direct evidence for the following steps, which are the mixing of the flour with water and the cooking.

However, the processes can be plausibly hypothesized, the researchers said.

"Rehydration is necessary for cooking and cooking is necessary to make the starch digestible," they said.

According to Stefano Grimaldi, professor at the University of Trento's department of philosophy, history and cultural heritage, the finding has several scientific implication of extraordinary importance.

"It shows that prehistoric people were able to administrate food resources despite the climate variability," Grimaldi told Discovery News "Such food processing also required organization in work tasks, which determines a social role of men and women, young and elder people. Moreover, the ability to generate reserves and surpluses of diversified food is one of the variables that can determine population growth," Grimaldi said.

This prehistoric pestle once ground oat grains into flour.

"Ardi" steered clear of abrasive, hard foods, such as nuts, tubers and tough grasses. Instead this ancestor seems to have gone for meat and large amounts of soft fruits from its Eastern Africa home.

A. afarensis

was another early East African member of the human family tree that walked upright, but still looked a lot like a chimp. It had "robust jaws and large, thick-enameled molars," according to new research in the journal Biology Letters that helps to explain what it, and other early human-ish species, ate. 

 The diet might have included seasonal consumption of very tough foods, such as dried grasses, in addition to wild-bird eggs, nuts, seeds, tubers, small prey and fruits.

"Nutcracker Man," also from East Africa, got that nickname due to powerful jaws and huge molars. Nuts were clearly a major part of its diet, along with bugs, fruits and probably whatever else it could sink its big teeth into. There's also evidence that the roots of papyrus, a plant later used to make paper, were on the menu.

Handy Man, from eastern and southern Africa, was not too proud to eat woody plants, leaves and the guts of hunted animals, teeth suggest.

The large and wide molars of East Africa’s

Homo rudolfensis

indicate that this species could do some major chewing, but the jaw -- smaller than that of earlier humans -- would have been a limitation.

Upright Man, living in parts of Africa and Asia, made stone tools suitable for butchering game of all sizes. There is also speculation that Upright Man had a sweet tooth, gorging on high-energy honey whenever lucky enough to find it. 
 Additionally, this human probably cooked some foods. 

"Cooking is what makes the human diet 'human,' and the most logical explanation for the advances in brain and body size over our ape ancestors," Richard Wrangham of Harvard University explained. "It's hard to imagine the leap to

Homo erectus

without cooking's nutritional benefits."

Butchery tools and bones of animals associated with Heidelberg Man suggest that this human hunted -- among other animals --- hippos, rhinos and megaloceros, one of the largest deer that ever lived. Heidelberg Man lived in Europe, Africa and possibly parts of China.

Hailing from parts of Europe and Asia, Neanderthals were meat lovers to the max, hunting mammoths, elephants, deer, reindeer, muskox and more. They also included some fruits, nuts and veggies on the side. Food wasn’t always plentiful for early humans, though. "Looking at these fossilized teeth, you can easily see these defects that showed Neanderthals periodically struggled nutritionally," says anthropologist Debbie Guatelli-Steinberg. She determined, however, that the struggles were no worse than those confronted by modern Eskimos, so lack of food probably didn’t do in Neanderthals.

Living on the Island of Flores, Indonesia, gave this "Hobbit" human access to some unusual prey. Animal bones associated with the Hobbits suggest they ate the pygmy elephant Stegodon, giant rats and possibly huge lizards, such as Komodo dragons.

Cooking techniques, sophisticated tools and an educated palate all added to the broad diet of our species. There is some evidence that early

Homo sapiens

killed -- and ate -- Neanderthals. The idea is perhaps less shocking when one considers that primate meat is still regularly consumed by certain people. Cannibalism has occurred in human history but was usually a last resort during a famine. The bottom line is that, for better and worse, humans and those who came before will eat almost anything.