Combine the fruit and sugar in a bowl, cover and leave to macerate in your refrigerator for 1-2 days. Halfway through the maceration process, mash the fruit and sugar together.
Drain the resulting syrup through a fine mesh sieve (the leftover berry pulp is great on pancakes) and mix with vinegar. Store in the refrigerator.
Recipe by The Domestic Front at https://www.thedomesticfront.com/juniper-bush-cocktail-and-mixed-berry-shrub/