Cut persimmon into quarters. Cut out stem part. Peel fruits. Some persimmon varieties have a jelly like seed pod in the fruit, take out if you find one.
Cut persimmons into chunks.
Place fruits into a large pot with the sugar, lemon juice, and squeezed out clean lemon halves.
Stir everything well and keep over high heat.
Bring to a rolling boil and reduce heat to a medium heat setting.
Allow the jam to cook and reduce. This can take 30-50 minutes.
When you think it looks cooked, blend jam smoothly.
Test if the jam is set by dropping some hot jam on an ice-cold plate and move the plate around. If the jam is running, it needs to reduce more. If it's not moving it's set. Repeat the process until it looks set. You can also test if your jam is set with a candy thermometer, 105 Celsius/220 Fahrenheit.
Pour hot jam into clean sterilized jars. Drop some rum, vodka, or similar to the lids to kill remaining germs.
Close jars tight with lids and turn upside down to create a vacuum. Allow to cool and store lid up on a shelf, away from direct sunlight, in a cool and dry place.
You can skip adding the lemon halves. The citrus rind contains a lot of natural pectins, hence why I add it. Pectin helps in preserving the jam. If you use the lemon halves, use only untreated organic lemon rinds, because you don't want chemicals in your jam.
1 serving equals 1 Teaspoon. The total quantity of the jam will be about 3 jars = 70 servings.