1. Combine water, dried hibiscus petals, cinnamon stick, ground cloves, ground nutmeg, and ground allspice in a large saucepan. 2. Bring the mixture to a boil over medium-high heat. 3. Once boiling, reduce heat to low and simmer gently for 10-15 minutes, allowing the flavors to infuse and the hibiscus to release its vibrant color. 4. Remove the saucepan from the heat and stir in the granulated sugar until dissolved. Taste and adjust sweetness if desired. 5. Carefully strain the tea through a fine-mesh sieve into a heatproof pitcher or container, discarding the solids. 6. Allow the spiced hibiscus tea to cool to room temperature, then refrigerate for at least 2 hours or until thoroughly chilled. 7. Serve over ice and garnish with a citrus slice or fresh mint if desired. Enjoy!