In a large saucepan on high heat, bring hibiscus flowers, 4 cups of water, and sugar to a boil.
Cover and simmer over low heat for 15 minutes.
Remove from heat and allow to cool to room temperature.
Using a colander, strain out the hibiscus flowers. Don't throw the flowers away! Save them to make candied hibiscus flowers.
Add the remaining four cups of water.
Stir and chill.
Serve over ice.
If you are using fresh hibiscus flowers, be sure to clean them well and use the petals only. Use 8 cups of them loosely packed to make the same amount of tea.If you prefer sweeter beverages, you can add another 1/4 cup of sugar. You can also leave the sugar off entirely if you prefer a more tart flavor.Try adding cinnamon or ginger for a fun twist.You can also add club soda instead of the water at the end of the recipe to make a fizzy version.