Not your typical tonic, the No. 5 combines lime and lemon juice with cinchona bark, the source of quinine for tonic. A char on fresh grapefruit skins helps to bring out bitter yet refreshing notes. Just a bit of sea salt helps highlight savory caramel notes and rounds out the flavor.
This mixer works well with any light spirit. Mix equal parts No. 5 + vodka + soda water in a tall glass over plenty of ice. Garnish with a lime wedge.