Remove the seeds from the washed sour cherries and cut them into small pieces.
Mix the fruits with the jelling sugar and bring everything to the boil while stirring. Boil for about 5 minutes until bubbling.
To refine, stir in some lemon juice or even a shot of rum, depending on your taste.
Now fill the prepared jars to the brim with the hot sour cherry jam, close immediately and let stand on the lid for about 5 minutes.