Bring the sugar and water to a boil in a medium saucepan. Simmer for 10 minutes over medium heat, stirring occasionally, until sugar has thoroughly dissolved.
Add the vinegar and boil for 15 to 20 minutes over medium heat, until a thick syrup forms. Remove the saucepan from the heat.
Wash 4 mint sprigs, pat dry and add them to the syrup. Allow to cool. R