Place the washed and cleaned of stems sour cherries in a 12 1/2 cups (3 L) jar and pour the sugar over them. Close them with a plug of cotton, keep them in a sunny spot for 20 days and then move them to an area with a constant temperature in the shade for fermentation.
After 3-4 weeks, drain the liquid. It has unlimited shelf life. Close the fruits into small jars and sterilize them for 10 minutes. They make for a wonderful appetizer for brandy.