Canola or vegetable oil, for greasing
2 bunches seedless red grapes on the vine
5 peaches, halved, pitted and quartered
Two 750-milliliter bottles white wine, such as pinot grigio
8 ounces simple syrup
8 ounces white tequila
Cook's Note: 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.