Add the pitted cherries to a big saucepan and bring to a boil on medium-high heat
Cook for 15 minutes, stirring regularly to cook some of the liquid down
Add sugar and lemon juice, and cook for 10 minutes
Take it from the fire and let it cool completely. At this point, it is a good time to check if the jam has started to set. If yes, you may skip the next cooking and cooling.
Bring the jam back to a boil and cook on medium-high for another 10 minutes.
Take it from the fire and let it cool completely.
Bring the jam back to a boil and cook on medium-high till it thickens to your liking. At this point, it might only need a few minutes.
Ladle into clean jars
Cover with lids and screw on bands finger-tight
Process in a water bath or steam canner for 20 minutes
Note: You can process this jam for 10 minutes (adjusting to your altitude), but in that case, you have to sterilize jars and lids beforehand. I process it for 20 minutes to save myself the extra work.
Recipe by Northern Homestead at https://northernhomestead.com/sour-cherry-jam-recipe-without-pectin/