How to Make It
Light a hardwood charcoal fire. Put the grapes on a perforated grill sheet or in a grill basket and grill over high heat, tossing occasionally, until they just start to burst, about 6 minutes. Transfer the grapes to a plate to cool completely.
Meanwhile, grill the orange and lemon wheels over high heat, turning once, until lightly charred, about 6 minutes. Transfer to a plate to cool completely.
In a large pitcher, combine the wine with the simple syrup, brandy and grilled fruit and stir well. Refrigerate until the sangria is chilled and the flavors are blended, at least 1 hour and up to 8 hours. Serve the sangria over ice.
To make simple syrup, combine equal amounts of sugar and water in a small saucepan and bring to a boil; simmer, stirring constantly, until the sugar is completely dissolved, about 3 minutes. Remove the syrup from the heat and let cool completely. The simple syrup can be refrigerated in a glass jar for up to 1 month.