For the calcium solution: Combine both ingredients using a handheld immersion blender to dissolve the calcium. Reserve refrigerated.
For the cherry jam: Boil the cherry purée, 80 percent of the sugar, and the calcium solution in a small sauce pot. In the meantime, combine the remaining sugar with the pectin to obtain an even mixture.
Add the pectin-sugar mixture to the cherry mixture by shearing it in with a handheld immersion blender.
Return to a boil for 1 minute while stirring with a whisk.
Pour the hot jam onto a half hotel pan to cool at room temperature.
Once it is cool you may pipe it into the dough-lined molds. If not using right away, keep refrigerated for up to 2 weeks.