Spicy Pickled Grapes

This recipe originally called for white vinegar but I subbed Chardonnay and Raspberry Champagne vinegar for a more delicate flavor. I have read that canning grapes makes them mushy and the finished product looks plenty soft, but I still think they will taste amazing.

3 cups grapes
2 cups vinegar

4 inch sprig of Rosemary
1/2 teaspoon chili flakes

Clean grapes in cold water, remove stems, and fill sterilized jars with grapes. Bring water, vinegar, rosemary, and chili flakes to a simmer. Pour hot brine into jars leaving 1/4 inch head room. Process jars immediately in a boiling water bath, 20 minutes for pints.