Ingredients

• 1 (2-inch) cinnamon stick
• 2 whole cloves
• 10 black peppercorns
• 2 (2- by 1-inch) strips fresh lemon zest
• 2 (2- by 1-inch) strips fresh orange zest
• 1/2 teaspoon unflavored gelatin (from one 1/4-oz envelope)
• 1 1/2 cups plus 1 tablespoon white grape juice
• 1 cup dry white wine
• 1/2 cup sugar
• Pinch of freshly grated nutmeg
• 1 teaspoon finely grated fresh lemon zest
• 2 cups mixed grapes, stemmed, seeded if necessary, and sliced (lengthwise or crosswise)
• Special equipment: a 5-inch square of cheesecloth; kitchen string

Instructions

1. Put cinnamon stick, cloves, peppercorns, and zest strips on cheesecloth and tie it closed.
2. Sprinkle gelatin over 1 tablespoon grape juice in a small cup and let soften about 1 minute.
3. Bring wine, remaining 1 1/2 cups white grape juice, sugar, nutmeg, and cheesecloth bag to a boil in a 1- to 2-quart saucepan, then remove from heat and add gelatin mixture, stirring with a metal spoon (see cooks' note, below) until dissolved.
4. Transfer soup to a bowl and chill, covered, in a larger bowl of ice and cold water in the refrigerator for at least 8 hours.
5. Just before serving, discard cheesecloth bag and add grated zest and grapes to soup.