Juice of 1 lemon, plus lemon half-moons or wedges for garnish
Ginger beer, to serve
Bourbon, whiskey, or vodka, for serving (optional)
Thyme sprigs, for garnish
In a large stockpot over medium heat, add the filtered water, blackberries, raspberries, honey, ginger, and salt. Bring to a boil and simmer until the berries have burst and released their juices, 20 to 25 minutes.
Strain through a fine-mesh sieve, add the lemon juice, and transfer to a fridge-safe vessel. Allow to cool completely.
To serve, add ice to lowball glasses and pour over the ginger berry juice to about two-thirds up the glass. Top with some ginger beer and alcohol (if using). Garnish with lemon half-moons or wedges and thyme sprigs.