Wine was a key part of the Byzantine diet. André Tchernia has estimated that the average Roman (or Byzantine) adult male drank about a liter per day. To put this in perspective, most wine is now sold in .75 liter bottles, and the big boxes of wine are 3 liters. So an adult male would want a bottle and a bit per day, or 2+ boxes a week.

Any time you do this kind of statistical history ("cliometrics"), you make a lot of assumptions. Tchernia assumed women would drink about .5 liters of wine per day, and children a bit less. He calculated that the average family consumed about 2 liters a day, and a city the size of Antioch (~150,000) needed to bring about 15 million liters of wine into its walls each year.

Why was wine so important? It was a terrific source of calories: 4-8 grams of carbs for every 100 grams of wine, or 40-80 g per liter, so adult males were getting 160-320 calories from their wine: about the same as eating a burger. Plus it's full of nutrients, particularly potassium and Vitamin C. In many ways, better than McDonalds. In an age when disease was endemic, the nutrients in wine helped replenish those lost to diarrhea. It was also safer to drink than most sources of water.

Much of this wine was probably not very good by anyone's standards. There was a booming market in posca, which was basically wine gone sour, possibly mixed with sweeteners or other flavors to make it taste better (we don't really know). Wikipedia claims that it was a popular drink, but most people who could to afford better did. To me it looks like most people - including soldiers drawing army rations and the urban poor - did the best with what they could get, which was a mass produced and cheaply processed quality of wine. The advantage was that it had already gone bad, so it had a pretty stable shelf life for shipping into cities or out to distant military posts.

Those who could afford better did so. They drank wines that were specially processed, blended, or local specialties, not altogether different from many of the varieties available today. Some of these ended up being very valuable commodities, rapidly exchanged over long distances. Many of the small farms we find littered across the Byzantine Near East were too small to support families cultivating grain, so it looks like even humble peasants or slaves might have participated in this lucrative trade (and maybe even kept some of the fancy wine for their own tables).

If you want to learn more, Michael Decker's Tilling the Hateful Earth (2009) is not quite as exciting as the title suggests, but it's impressively thorough and very easy to navigate. He has remarkably little to say about other alcoholic beverages, since they haven't left much of an archaeological trace, although Classicists might have more to say on that.