Zest the orange and slice the ginger root into small pieces. You do not need to peel the ginger as we are straining out the fruit and the skin of ginger root contains a lot of nutrition and flavour.
Place the cranberries and the water in a pan and bring to a boil. Cook for a few minutes until the berries begin to burst, then use a potato masher to crush them.
Remove from the heat and add the orange zest and ginger, then leave to combine for 2 hours.⠀
Add the sugar and heat the mixture again until it is all dissolved.
Strain over a bowl using a muslin cloth or sieve (but don't push the mixture through too much so that it stays clear.
Serve straight away or freeze in an airtight container to use as needed.