1. Thinly peel the fresh ginger, grate and mix with water in a large saucepan.
2. Bring to a boil and simmer for 4 minutes. Cover the pan and turn off the heat; leave for 24 hours.
3. Strain the liquid through a fine mesh sieve.
4. Add the lime juice and maple syrup or agave. Stir until dissolved. Serve chilled.
