Combine all ingredients in a large, non-reactive pot. Bring to a boil and then reduce temperature to a simmer. Stirring regularly, gently boil the jam until it reduces to a sticky, jammy mess. Cooking at a fairly rapid pace, it should take about an hour of cooking.
When the jam has cooked down sufficiently, remove from heat and fill jars, leaving 1/4 inch of head space. Wipe rims, apply lids and twist on rings. Process in a boiling water canner for 20 minutes.
When time is up, remove jars from water bath and allow them to cool. When jars are cool enough to handle, test seals. Store jars in a cool, dark place for up to one year.