How to Make It
1. Bring first 6 ingredients to a simmer in a small saucepan over medium-high; stir until sugar is dissolved. Remove pan from heat; let cool 10 minutes.
2. Remove a sliver from the stem end of each grape; reserve slivers for another use. Place grapes in a 1-quart jar or plastic container. Carefullly pour vinegar mixture over grapes; seal and refrigerate at least 1 hour or overnight.