1.
Juice the lemons.
2.
Peel and grate the ginger.
3.
Place the grated ginger and a liberal dash of the cayenne chilli into a piece of cheesecloth, and tie it into a knot.
4.
Let soak in the water.
5.
After 15 minutes or so, add the sugar, and the lemon juice.
6.
Chill, and serve.