Βρόμος, ὁ – Oats (Avena sativa)
Oats were quite uncommon ingredients in ancient beer. The earliest (potential) reference to beer that was made with oats is in the fourth c. CE (Julian the Apostate). The Romans considered oats an unappetizing grain, and its cost reflected this disinterest; it was the lowest priced grain in Diocletian’s Price Edict (301 CE).
Oats are often undifferentiated by Roman/Greek authors as a grain. Possibly, oats were not even extensively grown in certain periods of Greco-Roman antiquity. It is, thus, not surprising that we do not have many Greco-Roman sources reporting on oat beer. The popularity of oat beers throughout the Greco-Roman sphere of influence was either non-existent for centuries or it was not of interest to the authors, who were predominately oinophiles, writing about ancient wines.