2 cups fresh blackberries - rinsed, drained, and lightly crushed
2 cups white sugar
2 sprigs fresh thyme, or to taste (optional)
2 sprigs fresh sage, or to taste (optional)
1 cup white vinegar
Wash and sterilize a bowl or jar. Add blackberries; cover with sugar. Add thyme and sage. Stir well to combine. Cover with a lid or plastic wrap. Refrigerate, stirring occasionally, until a pool of juice and syrup forms around the blackberries, 1 to 2 days.
Remove thyme and sage from the bowl. Place a fine mesh strainer over a separate bowl and pour in blackberry mixture. Press lightly on the solids to expel all the juice.
Sterilize a glass jar or bottle. Pour in juice and add vinegar. Cover with a lid and shake gently to dissolve any remaining sugar. Let rest until flavors intensify, at least 1 day.