At yesterday's Twentieth Zoom, I gave a short presentation on aspects of the symposium, and this was a slide, with further info.
We don't know exactly what occurred at historical Twentieth gatherings...but here is some speculation:
There was either a large gathering at the Kepos gardens (perhaps no more than 50 people, and not as a "symposium") and/or there were small gatherings at various private homes which may have been up to 12 attendees plus their hetairai (female companions, as was the ancient Greek custom) and which followed the cultural format of a symposium.
Here is a bit more from yesterday's presentation:
Written records and literary accounts of symposia in Hellenistic Athens do exist, though they are largely fragmentary and frequently preserved as quotes within later Roman-era texts. While the most famous complete accounts of the Athenian symposium come from the Classical period (most notably the works of Plato and Xenophon), prominent Hellenistic philosophers, playwrights, and historians continued to write about and record the evolving nature of these drinking parties in Athens.
The Fragmentary Symposium of Epicurus: The most notable native written record from Hellenistic Athens is the lost Symposium written by the philosopher Epicurus. While the original text has not survived intact, extensive fragments and descriptions are preserved by later authors:
• Athenaeus of Naucratis provides critical commentary on Epicurus' work in his encyclopedic text, the Deipnosophistae ("Doctors at Dinner"). Athenaeus notes that Epicurus broke traditional conventions by featuring a dialogue composed entirely of philosophers (pejoratively dubbed "atom prophets") and skipping traditional structural preliminaries like formal libations to the gods.
• Plutarch also explicitly references Epicurus' Symposium, noting that the dialogue moved away from political theory to debate the physiological and scientific effects of wine and sex.
Kraters were central to the symposium both literally and culturally. The Krater or "mixing bowl," used for mixing wine and water, was placed at the center of the room. The Symposiasts, or the participants, reclined on their couches around the krater. Their couches were placed along the wall of the room, and this limited the number of men attending to between eight and twelve. Tables on which the wine and food was served, were slightly lower and placed in front of the couches.
The symposiarch would oversee the symposium. The main focus of his job was the dilution of the wine. It was up to him to decide how strong the wine would be depending on the type of discussion or entertainment that was expected for the evening Kraters were quite large, so they were not easily portable when filled. Thus, the wine-water mixture would be withdrawn from the krater with other vessels, such as a kyathos, an amphoreus, or a kylix.
Before dilution, wine in ancient Athens typically had an alcohol content of 9% to 15% ABV (alcohol by volume), though some sweet or concentrated varieties could reach up to 16% to 18% ABV.
Dilution and Consumption • Ancient Athenians almost never drank wine neat. Drinking unadulterated wine was considered a barbaric habit fit only for ruining one's mind or health. Wine was mixed with water in a large vessel called a krater before being served.
• Common Ratios: Typical mixing ratios ranged from 3 parts water to 1 part wine (3:1) to 5 parts water to 2 parts wine (5:2).
• Final Alcohol Strength: This heavy watering-down meant the actual cup of liquid consumed during a symposium or meal had a much lower alcohol content, usually resting around 2% to 5% ABV- similar to a modern light beer or cider.
• Athenians enhanced their wine to balance or mask off-tasting flavors, using three primary methods: Infusion during fermentation - herbs like thyme, oregano, or mint were bundled into porous linen cloths, weighted down, and submerged in the grape must. Amphora linings and sealants of sticky pine resin from the Aleppo pine were used. And when needed they also added fresh herbs or floral perfumes directly into the krater shortly before consumption.