Wash the sour cherries thoroughly and remove the stems and pits.

Layer the cherries and sugar in a large saucepan.

Cover and refrigerate for 8-12 hours or overnight until the cherries release their juices.

Place the saucepan over medium heat and add 1 cup of water.

Bring the mixture to a gentle boil, skimming off any foam that forms on the surface.

Simmer for 35-45 minutes, stirring occasionally until the syrup thickens.

Test the consistency by placing a few drops of syrup on a cold plate. If it moves slowly, the jam is ready.

Add the lemon juice and cook for an additional 2-3 minutes.

Remove from the heat and allow the jam to cool completely.

Transfer the jam to sterilized jars and seal tightly.