Demographic breakdown of
Roman population
From late Republican times through till at least the third century A.D., Rome was a home to some 700,000 citizens, of which only about 55% were adults (cf. 71% in the modern population). Accepting that demographic breakdown, a calculation for wine consumption would run as follows. With pre-adolescents and adolescent females not consuming wine at all, adolescent males and adult females consuming only about 0.3 sextarii per day, and adult males consuming 1.5 sextarii per day, the total consumption of Rome’s citizenry will have been about 368,970 sextarii per day.
This is equivalent to about 19.2 million U.S. gallons per year (or 27.4 U.S gallons per capita).