The oldest yet discovered evidence for flour production is from several Epi-Paleolithic and Upper Paleolithic sites in Europe. For example, evidence was found at the 25,000 year old Gravettian hunter-gatherer campsite of Bilancino, near Florence, Italy. Among the 15,000 artifacts collected from the site was a broken piece of sandstone with a concave depression worn into one side.
A smaller stone, broken from the first, is interpreted as a grinder. Usewear patterns revealed a back and forth method of grinding. Starch grains found on both grinder and grindstone were identified as from cattails, reeds and grasses (Aranguen et al. 2007). The paleolithic sites of Kostenki 16 (Russia) and Pavlov VI (Czech Republic) also have revealed flour production evidence, indicating the cooking method was known throughout Europe at least 30,000 years ago. (Revedin et al. 2010).
Other examples of ground stone grinding slabs and pestles have been found in the Epi-Paleolithic Kebaran site of 'Uyun al-Hammam in the Jordan Valley, and a slab at Ohalo II in Israel had starch grains on the top in association with artifacts dated 23,000 years ago (Maher, Richter and Stock 2012).
The earliest known use of a grinder, however, is not from organic materials, but from the use of an abalone shell and a round stone to grind red ochre at Blombos Cave, South Africa, about 100,000 years ago, so it is possible that grinding plants may have occurred much earlier than 30,000 years ago. (Henshilwood et al 2011, Wadley 2010)
Sources
Aranguren B, Becattini R, Mariotti Lippi M, and Revedin A. 2007. Grinding flour in Upper Palaeolithic Europe (25 000 years bp). Antiquity 81:845–855.
Henshilwood C, D'Errico F, Van Niekerk K, Coquinot Y, Jacobs Z, Lauritzen S-E, Menu M, and Garcia-Moreno R. 2011. A 100,000-Year-Old Ochre-Processing Workshop at Blombos Cave, South Africa. Science 334:219-222.
Maher LA, Richter T, and Stock JT. 2012. The Pre-Natufian Epipaleolithic: Long-term Behavioral Trends in the Levant. Evolutionary Anthropology: Issues, News, and Reviews 21(2):69-81.
Revedin A, Aranguren B, Becattini R, Longo L, Marconi E, Mariotti Lippi M, Skakun N, Sinitsyn A, Spiridonova E, and Svoboda J. 2010. Thirty thousand-year-old evidence of plant food processing. Proceedings of the National Academy of Sciences 107(44):18815-18819.
Wadley L. 2010. Cemented ash as a receptacle or work surface for ochre powder production at Sibudu, South Africa, 58,000 years ago. Journal of Archaeological Science 37(10):2397-2406.
Also see the bibliography.
