In a large pan, combine the cranberries and water and bring to a boil over high heat. Once boiling, reduce the heat to a simmer. Cook for a further 20 minutes, or until the cranberries are softened, and the majority have popped.

Pour the mixture through a sieve or nut milk bag, allowing all the liquid through and then pressing with the back of your spoon or squeezing with your hands to get as much excess liquid from the cranberries as possible. Mix well, add your sweetener of choice to taste, and allow the juice to cool down.

If using granulated sugar, you may need to return it to the pan to reheat until the sugar dissolves. Once cool, drink immediately or transfer the juice to an airtight jar/bottle in the fridge.