01 - In a small saucepan, combine the granulated sugar and water. Heat over medium heat, stirring continuously until the sugar fully dissolves. Remove from heat and allow the syrup to cool completely to room temperature.
02 - Juice the pink grapefruits. Strain the fresh juice through a fine-mesh sieve to remove any pulp and seeds. Measure 2 cups of the strained grapefruit juice.
03 - In a large mixing bowl, combine the cooled simple syrup, measured grapefruit juice, fresh lemon juice, grapefruit zest (if desired), and a pinch of salt. Whisk thoroughly to ensure all ingredients are well incorporated.
04 - Cover the sorbet mixture and refrigerate for a minimum of 1 hour, or until thoroughly chilled.
05 - Pour the chilled mixture into an ice cream maker. Churn according to the manufacturer's instructions, typically for 20-25 minutes, until the mixture achieves a soft, frozen sorbet consistency.
06 - Transfer the freshly churned sorbet into a freezer-safe container. Cover tightly and freeze for at least 3 hours, or until the sorbet is completely firm.
07 - Before serving, allow the sorbet to sit at room temperature for approximately 5 minutes to soften slightly, making it easier to scoop and enjoy.