Prep jars and canning pot.

Combine plums, 2 cups of sugar, and lemon juice and bring to a boil. Once the fruit is tender, add calcium water, stir well and return to a boil.

Whisk remaining sugar, pectin powder, cinnamon, nutmeg and lemon zest together and add them to the cooking fruit.

Cook jam at a rapid boil for another 3-5 minutes, until it begins to thicken.

Turn off the heat under the jam and fill jars. Wipe rims, apply lids and rings and process jars in a boiling water bath for 10 minutes.

When time is up, remove jars from canner and let cool on a folded kitchen towel. When jars are cool enough to handle, remove rings and test seals. Any unsealed jars should be refrigerated. All sealed jars are safe for shelf storage.