Combine all ingredients in a heavy saucepan. Bring to a boil over medium-high heat. Mash the berries with a potato masher or back of a spoon. Lower the heat so that the mixture continues to boil gently. Continue to cook uncovered, for 20 -25 minutes or until the mixture is thick. Cool to room temperature, the jam will gel as it cools. Store in clean containers in the fridge for up to a month or in the freezer for up to a year.