Bring 1 litre (4 cups) of water to a boil with the cranberries, cinnamon sticks, cloves, juniper berries and sugar. Stir occasionally until the sugar is dissolved and remove from the heat when all berries have burst. This only takes a few minutes. Leave to brew for a few hours. Strain and bring to a boil again. Add the juices, heat them briefly and serve the tea in warm bowls.