Mix together sauternes, water, and sugar in a deep saucepan. Bring to a simmer over medium heat.

Lower peaches into simmering liquid and blanch just long enough to loosen their skins, about 2 minutes. Remove peaches with a slotted spoon, then carefully peel and place in a deep bowl. Immediately cover peaches themselves with plastic wrap to keep them from turning brown.

Continue to simmer poaching liquid until it has reduced by half and thickened slightly, about 30 minutes. Remove saucepan from heat and allow syrup to cool completely.

Pour the cooled syrup over peaches and set aside to macerate for 2 - 4 hours before serving.