01 - Bring water to a rolling boil in a saucepan over high heat.
02 - Remove saucepan from heat, stir in dried hibiscus flowers, cover and let steep for 10 minutes to extract full flavor and color.
03 - Pour mixture through a fine mesh strainer into a pitcher, pressing flowers to extract liquid. Discard spent flowers.
04 - Stir honey or agave syrup into warm tea until completely dissolved, then add fresh lemon juice and mix thoroughly.
05 - Allow tea to cool to room temperature, then refrigerate for at least 1 hour until thoroughly chilled.
06 - Fill glasses with ice cubes, pour chilled hibiscus tea over ice, and garnish with fresh lemon slices and mint sprigs if desired.