Fill pot with 2 quarts water. Add hibiscus, mint, and ginger.
Bring to boil. Reduce to simmer and simmer for 15 minutes, partially covered.
Remove from heat and let stand until fully cooled, several hours.
Remove hibiscus, mint, and ginger and place those ingredients in a large bowl.
Add 2 cups water to bowl with hibiscus, etc., and let sit for 10 minutes.
Meanwhile, pour cooled liquid through sieve into a large pot.
After hibiscus, etc., have steeped, pour the water from the hibiscus, etc., into the rest of the liquid. With your hands, squeeze as much liquid as you can out of the hibiscus, etc.
Stir in sugar to taste, a little at a time, until the sugar disolves.
Chill in refrigerator.