|Prep time: 45 minutes||Cooking time: 1 1⁄2 hours||Total time: 2 1⁄4 hours|
Simmer the plums and water together in a pan until soft.
Test for pectin and add as required.
(Plums tend to have a medium to high pectin content but obviously varies with varieties, mine are fairly low - they are a greeny/yellow plum I'll try and find out what variety)
Add the sugar, stirring it in until dissolved. (Make sure all sugar is disolved before bringing to the boil!)
Boil rapidly until the jam sets when tested (remove the stones as they float to the top).
Remove any scum from the top and pot into sterile pots while still hot.
Making with the stones in (hung in a muslin bag or otherwise fish out prior to bottling) reportedly increases pectin content in Jam as it is contained in the stones, or you could add apple etc for a natural pectin source.