Cali Grapefruit 2 oz. white rum (recipe recommends Caliche Rum, crafted by Cindy Crawford's husband Rande Gerber)
½ oz. bitters (recipe recommends Campari)
1 oz. grapefruit juice
¼ oz. agave nectar
Combine all ingredients in a shaker filled with ice, and shake until chilled. Strain into a highball glass and top with soda water.
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