Wash the jar with warm, soapy water and do not dry.

Pack the blueberries into the jar and set aside while you create the brine.

In a small, nonreactive saucepan, bring the remaining ingredients to a simmer for 10 minutes.

Remove the brine from the heat and pour over the berries through a fine-mesh strainer.

Cap loosely and allow the jar to cool on the countertop for an hour before placing the jar in the refrigerator.

Begin eating blueberry pickles after 1 week, and consume within 6 months for best flavor. Use the leftover brine for shrub cocktails or sodas—using 1 tablespoon for every 6 ounces of club soda.