Grinding plant matter into flour also has important other implications about the structure of hunter-gatherer subsistence and social life, however. To understand these, it's helpful to look at some of the earliest traces of flour production in the archaeological record, one example of which is provided by the Gravettian site of Bilancino, in Tuscany, Italy, which dates to about 25,000BP uncal. (Aranguren et al. 2007), and which I mentioned briefly earlier. Bilancino is a very interesting site: because of preservation issues, namely the acidic nature of the sediment there, no bone was preserved at all. This has forced the investigators to thoroughly investigate other kinds of archaeological remains that are not usually the focus of such intensive scrutiny in many Paleolithic studies. This includes notably charcoal, pollen and starch grain recovered from the surface of a grindstone. These efforts have paid off in spades by revealing that the occupants of Bilancino had been grinding cattail (Typha latifolia), likely its roots, as well as wild grasses to produce flour.
Aranguren et al. (2007) explicitly discuss the potential impact of flour on Paleolithic lifeways. They specificallyhighlight that it "implies the availability of an elaborate product, a flour, with high energy content, that is rich in carbohydrates, easily storable and transportable, to make a kind of bread (biscuits) or a porridge" (Aranguren 2007: 853). This means that plant material could be preserved and stored for much longer periods of time, which effectively can provide carbs during seasons such as winter during which they are normally difficult if not impossible to obtain. Also, it provides a subsistence items that serves as a buffer against the fluctuating availability of other types of subsitence resources, such as animal tissue. Lastly, because flour is easily ingested and digested, it also provides a foodstuff that both very young and very old members of a group can consume - and maybe even produce while adults are off procuring other things. This means that survival to adulthood and into old age can be facilitated, which has the potential of significantly reorganizing the way labor is divided within a society, and increasing the generational knowledge available to given forager groups.
Aranguren,Biancamaria, Becattini, Roberto, Mariotti Lippi, Marta, & Revedin, Anna (2007). Grinding flour in Upper Palaeolithic Europe (25000 years bp) Antiquity, 81 (314), 845-855
HILL JR, M. (2008). Variation in Paleoindian fauna use on the Great Plains and Rocky Mountains of North America Quaternary International, 191 (1), 34-52 DOI: 10.1016/j.quaint.2007.10.004