Wait at least 24 hours before using. Try these tasty berries on crusty bread with a smear of goat cheese and a sprinkle of fresh thyme!
In a large bowl, add vinegars, water and sugar whisking to dissolve sugar. Add salt and stir.
Pack quart jar with blueberries and thin sliced red onion.
Pour liquid over blueberries and cap jar. Keep in refrigerator for up to one week.