Stir vigorously until the mixing glass becomes frosty.
Strain into a rocks glass over two-inch ice cube.
*Concord grape shrub:
6 cups Concord grapes, thoroughly rinsed
2 cups Granulated sugar
1 cup White wine vinegar
Combine Concord grapes with sugar and gently mash the fruit to release its juice. Cover with plastic wrap and let sit overnight in the fridge.
Strain grape juice through a fine mesh strainer by letting it sit for at least half an hour. Add the vinegar to the juice. Using a funnel, strain the shrub into a glass jar. Can be stored for up to three weeks.