Peel the mandarins, making sure that little of the white skin remains on the skin. Put the mandarin peel (use the pulp elsewhere) together with the alcohol in a large container, cover with a cloth and let it steep for 13 days in a dark place. Strain the pods after the 13 days.
Bring the water with the sugar to the boil and stir until the sugar is dissolved, allow to cool a little and mix the sugar syrup with the alcohol. Fill the liqueur into bottles.