Rosella jam is made from the fleshy red calyx and bracts that surround the green seedpod of the plant. Harvest the crop before it becomes tough and the seedpod discolours. You will need to half fill a 9-litre bucket with rosella fruit for the following recipe- or you can adjust the amounts accordingly. Rosella seedlings are available through local nurseries. Six home grown plants will provide plenty of fruit for several batches of jam. Individual plants grow around 1.5m high and 1m wide.
Soak the fruit for a few minutes in a sink full of cold water and then drain. Then separate the red calyx (the fleshy cover surrounding the seedpod) from the seedpod.) An easy way to do this is using an apple corer pushed hard against the base of the calyx; the calyx will then separate from the seedpod. Put the red calyx into a bowl and the seedpods into a saucepan. Cover the seedpods with water and simmer for 10-15 minutes, until soft and translucent in appearance. Strain the seedpods through a sieve and dispose of the seedpods, reserving the liquid. This process extracts pectin from the seedpods to help the jam set. Then pour the liquid back into a large saucepan, add the red calyx, apple & lemon and simmer gently until they are very soft.
Measure this fruit pulp and add cup for cup of sugar to fruit (or for larger amounts, 1 litre of fruit pulp = 1 kilo of sugar).
Stir over a gentle heat until the sugar is completely dissolved and then bring to the boil. The jam will froth high in the saucepan and so needs to be no more than half full before you start it boiling. Test for setting by putting a saucer in the freezer to chill, then put a teaspoonful of jam on the saucer, wait for it to cool slightly and then push the top of it with your finger. If it crinkles it is cooked. Another sign that it is setting to watch for is when the jam stops frothing and settles down to a hard boil.
As the jam reaches setting point it is also most likely to stick and burn so pay close attention and stir often. Remember that the setting of a jam is a chemical reaction between the fruit acid, the sugar and the pectin, not an evaporative process. Jams set as they cool, if over-cooked the setting point may be passed and instead a thick syrup rather than a gel is formed.
Bottle the jam into clean hot jars and seal immediately.