Put the fruit, sugar and vinegar in a large jar, and add the herb sprig and spice, if using (a a little goes a long way here).
Seal and shake energetically for about 30 seconds, then store out of direct sunlight for a week or two, shaking the mix once a day to help it infuse.
Strain out the fruit pulp, decant the shrub into a clean bottle and store in the fridge to enjoy diluted with sparkling or still water.