Wash the grapes well and remove them from the stems. Place in a clean quart-size jar.

In a small saucepan set over medium-high heat, combine the vinegar, sugar, salt, whole black peppercorns, cinnamon stick, cardamom pods, dried chile pepper, and ground allspice. Bring to a boil, then reduce the heat to medium-low, stirring occasionally to dissolve the sugar, 3-5 minutes.

Remove the brine from the heat and let cool until warm but not hot.

Pour the brine over the grapes and close the jar. Let cool to room temperature before refrigerating. Let sit for 24 hours in the refrigerator before serving. The grapes will stay delicious in the refrigerator for about 3 weeks.