We are lucky that burnt grains have a good tendency to survive in soils so there is lots of reliable evidence of grain use in ancient times. Archaeology uses evidence of ancient grains to get a picture of what our ancestors ate (and drank).
Wild barley spread north following the retreat of the glaciers after the last Ice Age. Barley was being cultivated as far south as the dead sea around nine and a half thousand years ago, and as far north as the Scottish borders. Barley’s long list of health benefits include: 18 amino acids, sodium, potassium, calcium, magnesium antioxidants, iron, copper, manganese, zinc, beta carotene, vitamins B1, B2, B6, C, and folic acid. It was also a raw material for making beer, which was sterile and therefore often safer to drink than water. By 6000 BC the farming of barley had spread into northern Africa, along the Nile valley.
Beer can be made very easily in warm climates. Watered down barley porridge is all that you need. Wild yeasts and warm temperatures do the rest in a remarkeably quick time. From experimentation in the UK I have found that in less than 5 hours a brew with more than 3% alcohol can be achieved when conditions are right. It is easy to imagine a scenario of a half eaten plate of Ga’at (an Ethiopian stiff porridge, made traditionally with barley flour) sitting in a washing bowl unattended for a few hours in the sun. By evening there could be a delicious beery smell and a tasty drink that was sterilized.
Modern wheat (Triticum aestivum) has its roots in 3 varieties of grain that have been harvested in Europe and the Near East for over 9000 years. These three are called spelt, einkorn and emmer.
Einkorn was a tough grain grown in europe since mesolithic times.There is evidence of einkorn farming in the Karacadag Mountains, in southeast Turkey 11,000 years ago and also around Jericho about the same time. its use decreased in the bronze age with the growing popularity of newer varieties of wheat and einkorn is rarely grown today.
Emmer, an original staple of farming in the the levant, has small grains and is related to the modern durum wheat. Emmer was eaten by the ancient egyptians and is still farmed today in a few areas.
Spelt has a distinctly nutty flavour and its grains are longer and more pointed than modern wheat. Spelt is planted in Autumn and grows over winter to be harvested the following summer. Spelt has a strong husk and so splitting the wheat from the chaff is achieved only by threshing and winnowing.
Both Archaeology and historical records show Millet was being harvested on the upper Nile near Khartoum in Sudan around 6000 BC.