- 9 ounces fresh blackberries (about 1 1/2 cups)
- 1 cup sugar
- 2 cups chilled dry gin
- 3/4 cup fresh lemon juice
- 2 cups chilled club soda
- Lemon wheels (for serving)
- Bring blackberries, sugar, and 1/2 cup water to a boil in a medium saucepan, stirring until sugar is dissolved. Reduce heat so that liquid is at a simmer and cook, stirring occasionally, until fruit is very soft, 20–25 minutes. Let blackberry syrup cool, then strain through a fine-mesh sieve into a large pitcher, pressing on fruit to extract as much liquid as you possibly can; discard solids.