Chop the persimmons into small chunks, leaving the skin on, and place in a large saucepan.
Add the sugar, orange zest, ginger, water and lemon juice and mix.
Heat gently without a lid, stirring regularly, until the fruit has sorted and the sugar has dissolved.
Turn up the heat and boil rapidly without a lid for about 15 minutes.
While the jam is cooking, place the glass jars and lids, with the lids removed, on a metal baking sheet in the oven at a low temperature. Heat the jars and lids for about 10 minutes to sterilise them.
Using a teaspoon, place a small amount of the jam on one of the chilled plates from the freezer. If the jam sticks to the plate and does not slide off when the plate is tilted the jam has reached setting point and is ready. If the jam is not ready, continue to boil rapidly for another 5 minutes or so and then test again.
When the jam has reached setting point, remove from the heat for a few minutes to cool slightly.
Transfer the jam into the sterilised jars while the jam and the jars are still warm. Fill the jars to just below the top, making sure there are no air bubbles and then add the lids.