Bring sugar and 1 litre of water to the boil in a large pot. Peel and slice the ginger. Clean lemon grass and cut in half lengthwise. Add lemon grass and ginger to the sugar water and simmer for about 10 minutes. Then let it cool down and put it in a cool place for about 1 hour
Wash the limes, grate them dry and cut them into large cubes. Pour 1.5 litres of mineral water over the sugar mixture and add the limes. Serve in glasses with ice cubes
waiting time approx. 1 1/2 hours