1 TBS dried rose flower (available at botanical.com and some specialty groceries)
Combine the ginger, sugar, lemon juice and lime juice with 6 C water and bring to a gentle boil.
Mix the yeast with ¾ C warm water and set aside.
After 30 minutes, remove the ginger solution form the heat. Add the hibiscus and rose flower, stir and let sit for 10 minutes.
Add 10 C cold water and strain into a second container.
Stir in the yeast solution.
Funnel liquid into two 2 liter bottles (or the equivalent) to an inch below the cap, adding water if necessary. Seal the bottles and store at room temperature for 24 hours.
Refrigerate to slow/stop the yeast and serve cold.