Instructions

1. Wash the blueberries thoroughly to remove any dirt and place them in a nonreactive 1-pint/½-liter container, such as a glass jar or fermentation crock. In a small bowl stir together the water and salt until the salt has dissolved. Pour over the berries and mix well.
2. Place a piece of plastic wrap directly on the surface of the berries to keep them submerged in the brine; if you have a fermentation weight this is a good time to use it.Seal the container, using a lid with an airlock if you have one; if you don’t, open the container every few days to release carbon dioxide buildup and check for mold. Place the container in a clean, low-light area with an ambient temperature of 60° to 68°F/16°C to 20°C and leave until the berries taste tart and sour, 10 days to 2 weeks. 
3. Store the brined berries in the refrigerator, where they’ll keep for at least 6 months.Their flavor continues to improve as they age. Makes 1 cup.