Brachot 42 - When is a meal complete?
As soon as one completes his meal, he is not allowed to eat anything else until he says a complete after-meal blessing. Rav Pappa visited the house of Rav Huna, and after they finished their meal, something else was brought to Rav Pappa, and he started eating. The students asked him, "One who finishes eating is not allowed to eat anymore!?" He answered that they were misquating the rule, it's "One who completes the meal and does not intend to eat anymore." Rava and Rabbi Zeira were eating at the house of the Exilarch . After the servants removed each guest's individual tray, the Exilarch sent them more food, but Rabbi Zeira did not eat it. Rava told him, "You may think that you are finished, but being guests, we rely on the Exilarch to end the meal."
In the early days, they would start the festival meal with wine and desserts, then continue with the meal, also accompanied by wine, and then again serve more wine with desserts after the meal has ended. One who said a blessing on the wine before the meal would also include the after-meal wine in this blessing, because these two went together. However, he did not include the wine that came during the meal, because that wine had a different purpose - it came for the food courses in the meal.
Art: Anthonie Palamedesz - A servant offering a glass of wine to an elegant couple