If your fruit is waxed then you will need to wash off the wax from the skin of the fruit first by giving it a light scrub. Cut the oranges, lemons and grapefruit into quarters then with a very sharp knife remove the flesh from the skin and the pith.
Cut into short thin strips. To achieve this, cut the peel lengthways again. You might need to cut the lemon peel once, the orange peel twice more and the grapefruit peel three times more to get even sized pieces. Then cut widthways into short thin strips.
Weigh the peel, you should have around 450g.
Place the peel into a large saucepan with the water then bring to the boil. Turn the heat down to low, cover and simmer for 1 hour.
Remove from the heat and drain over a large bowl to reserve the cooking water. Weigh out the cooking water, you need 1140g (5 ¾ cups) and pour back into the saucepan. Top up with more water if you don't have enough.
Add 900g (4 ½ cups) to the water and bring to a gentle boil, simmer for 10 minutes until the sugar has dissolved.
Place the peel in a large bowl and pour the sugar syrup over. Allow to cool then cover and leave to soak for 24 hours.