Boil the preserving jars for 10 minutes in plenty of water and dry on a clean dish towel. You will need jars with more than 1 litre (4 cups) in volume. Finely chop the cranberries in the food processor. Place in the preserving jars and add the lemon and orange zest. Add the vodka and spices. Bring the water and sugar to a boil. Add the syrup to the jars and immediately close the lids. Leave to ferment in a dark place for 1 month. Shake the jars every day. Place a cheesecloth or dish towel in a strainer over a large tray or jar. Strain the liquid. Thoroughly wring out the cloth, removing all moisture. If necessary, again pour the liquid through a coffee filter for an attractive clear liqueur. Pour into a clean bottle. It can be drunk immediately, but you can save it for a year.