In a large pot or Dutch oven over high heat, bring 10 cups of water to a boil. Lower the heat to low, and add the sorrel (hibiscus), ginger, cinnamon, star anise, cloves and orange peel.
Simmer for about 8 minutes, then remove from the heat.
Allow the mixture to sit until cool enough to refrigerate. Place the mixture in an airtight container (without straining the solids), and let it steep in the refrigerator for 8 hours and up to 2 days.
Make the simple syrup: Add the sugar and water to a small saucepan and heat over medium heat stirring until the sugar is dissolved. Remove from the heat and allow to cool.
Strain the liquid through a fine-mesh strainer or sieve into a pitcher and discard all the solids.
Stir in some of the simple syrup into the strained sorrel until you reach the desired level of sweetness. Serve over ice with orange slices if desired.
You can also serve this drink with rum, on the rocks.