This riff on old-fashioned switchel uses fresh ginger instead of powdered, and it includes plenty of blackberries, which give the drink a gorgeous pink color and a vibrant, summery flavor. Serve it over ice with a sprig of mint.
Add all the ingredients to a saucepan and bring to a boil over medium-high heat. Turn down the heat to medium-low and simmer for about 15 minutes. Mash the softened berries into the liquid, and continue simmering for another 5 minutes.
Strain the switchel, discarding the solids. Refrigerate overnight. Serve cold over ice.