1 cup fresh blueberries
1 cup white sugar
1 cup red wine vinegar
1/2 teaspoon whole black peppercorns
1 1/2 fluid ounces bourbon
3 fluid ounces ginger beer
Puree blueberries, sugar, and red wine vinegar in a blender. Add peppercorns. Chill shrub, covered, 4 hours to 2 days. Strain.
In a cocktail shaker half-filled with ice, combine 2 fluid ounces blueberry shrub and bourbon. Shake until very cold.
Strain into an ice-filled pint glass. Top with ginger beer. Garnish with additional blueberries or a lime wedge.