I suppose it all depends on how gravity works. The common assumption is that gravity pulls everything downwards regardless of where you stand on the planet. In this case, there are two options. Option 1: the wine splashes off of the edge in the same way water splashes everywhere when you clean a spoon wrong. Option 2: since wine is a liquid, the surface tension may result in the wine clinging onto earth, achieving the same flooding effect as the wine does on a globe. However, I also know of another theory. According to a Vsauce video I found, gravity would actually attract objects towards the center of the disk. This means that as you move further from the North Pole, gravity cease to pull you downwards, but sideways. **Vsauce - "Is Earth Actually Flat?" added to the Court Record.** In this case, the wine will be less likely to escape over the flat earth's edges, and will instead agglomerate as a massive drop of liquid on the center of the planet. In other words... **Slams Desk** Wine would turn the flat earth into a spherical waterworld!