The elderflower herbs or liqueur provide a quiet floral note.
Make Ahead: The syrup can be refrigerated in an airtight container for up to 5 days.
Servings: 30 - 32 ounces
- For the syrup
- 4 teaspoons elderflower herb or liqueur
- Finely grated zest of 1/2 grapefruit
- 2 cups just-boiled water
- Generous 1/2 cup (4 ounces) sugar
- Pinch kosher salt
- For the tonic
- 3/4 cup freshly squeezed lemon juice (from 2 1/2 large lemons)
- 1 cup water
- 2 teaspoons quinine (red cinchona bark) powder
For the syrup: Combine the elderflower herb or liqueur, grapefruit zest and water in a heatproof bowl for 30 minutes. Strain through a fine-mesh strainer, then funnel into a pitcher. Add the sugar and salt, stirring to dissolve. Refrigerate until well chilled.
For the tonic: Combine the syrup, lemon juice, water and quinine bark powder in a pitcher; stir to mix well. Strain through a fine-mesh strainer, then funnel into a 1-quart soda siphon. Charge with a CO2 cartridge according to the manufacturer's directions.
Pour into tall glasses filled with ice.
From Adam Bernbach at Estadio in Dupont Circle.
Tested by Nicole Schofer.
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