Begin by bringing 4 cups of water to a rolling boil in a large pot over medium-high heat.

Once the water reaches a boil, remove it from heat and add 1 cup of dried hibiscus flowers. Stir gently and let steep for 20 to 25 minutes.

Carefully pour the hibiscus mixture through a fine-mesh strainer into a bowl or pitcher, stir in sugar to taste.

Allow the strained hibiscus liquid to cool at room temperature for 30 minutes, then refrigerate for at least 1 hour.

Pour the Sweet Hibiscus Agua Fresca over ice-filled glasses and garnish with a slice of lime.