This is an easy jam to make purely requiring equal quantities of pitted fruit and white sugar plus the juice of one lemon per kilo of sugar.
First wash the fruits thoroughly and slice them in half in order to de-pit them. This fruit is unusual in that it has two seeds and they need to prized out.
Then pop them in a blender - skins and all to mush up to an even pulp.
Weigh the fruit at this point so you can then combine with equal amounts of white sugar. N.B. refined sugar is best as it allows the maximum colour of the fruit to shine through, raw sugar tends to dull it a bit.
Add to a stainless steel saucepan (no aluminium or iron pots as the acidity of the fruit will impart a metallic taste to the finished jam).
Put fruit, sugar and lemon juice into the saucepan, stir together on a medium heat until all the sugar is dissolved, continue to stir until the mix has reached a rolling boil. Once it has reached a rolling boil, stir occasionally to ensure the mix doesn’t stick to the bottom of the pan.
It will take approximately 60 minutes to reach a setting point, at this stage you will notice that the mixture has become a more jammy consistency and the bubbles in the liquid seem larger.
If you have a jam thermometer the setting point is reached at 105°C. Still test using the Freezer Test, as a temp of 105°C is only an indication and the jam may need to cook longer.
If you don’t have a jam thermometer, you will need to test the jam once the liquid looks more jam-like
Freezer Test
You need to place 2 plates in the freezer when you are collecting all the ingredients.
Take one plate from the freezer and place a small dollop of jam onto the plate and return it to the freezer and leave for 1minute.
Take the plate out, use your finger to push the side of the dollop, if the jam forms a skin and crinkles then the jam is ready. If not continue to cook the mix and retest every few minutes. Don’t forget to wash your plate and return it to the freezer.
Note: sometimes the jam will take up to 90mins to set. If it looks like it’s not going to set you can add Pectin, the quantities and instructions will be on the pack.
Whilst the jam is cooking, turn the oven onto 160°C, when the jam has reached its setting point remove from heat and allow to sit, then place your clean jars into the oven to sterilise for 5-10mins.
Take the jars from the oven and pour the jam into the jars. BE CAREFUL THE JAM WILL BE VERY HOT AND CAN CAUSE NASTY BURNS.
Add a disc of baking paper on top to minimize contact with air, attach the lid and leave to cool. As the jam cools the lids will start to make a popping sound – this is a good sound it shows that the lid seal is good and is caused by the lid is being pulled inwards as the cooling air contracts.