Pack grapes into 4 (1-pt.) canning jars with lids. Add 1 rosemary sprig to each jar.
Bring vinegar, next 4 ingredients, 1 cup water, and remaining 2 rosemary sprigs to a simmer in a medium saucepan. Remove from heat, and discard rosemary sprigs. Pour hot vinegar mixture over grapes. Cover loosely, and let cool to room temperature (about 30 minutes). Seal and chill 1 hour before serving. Store in refrigerator up to 1 week.