General rule is 1kg plums to 1kg sugar.
Remove seeds from plums and put in large saucepan, add a dash of water (not always needed but I generally it in a tablespoon or so).
Cook the plums down until they start to breakdown a little.
Add sugar (make sure you dissolve the sugar), bring to the boil and cook for around 20-30 minutes or until the jam sets on the saucer. Stir frequently.
You may need to turn the heat on the stove down a little, make sure that the jam is still bubbling but not boiling like mad.
You should not need jamsetta for plums. I have only ever used it for berries that I have frozen and made into jam later on.
*** don't let the jam stick to the bottom of the pan. If it sticks it will be ruined.
***leave jam to cool a bit before pouring into jars. If the jam is too hot and the jar too cool the jar will break.
Make sure your jars are very clean. I wash in very hot soapy water and rinse in very hot water. Lids too. I then boil the kettle and pour boiling water into my jars and leave to sit whilst cooking the jam. Once my jam has cooled slightly, I empty the still very hot water out of the jars (shaking out all of the drips of water left behind) and then pour the jam.
This post has been edited by jupiter123: 10/02/2013, 09:32 AM