Spiced Plum Jelly

I love plums - in fact a lot of the preserves I put down each year tend to be plum related.  This one in particular goes well with pheasant and chicken (and also perks up gravy) and also goes well with cheese. 

Ingredients:

1.6kg red plums
400ml cider vinegar
150ml Port
1 cinnamon stick
8 cloves
8 green cardamom pods
700g granulated sugar

Method

1. Cut up the plums anmd place them with their stones into a very large heavy based saucepan.
2. Add the vinegar, port, spices and bring to the boil, cover and then simmer for about an hour.
3. Tip the contents of the pan into a jelly bag suspended over a bowl. Allow to drip through I usually allow overnight as a minimum. Do not squeeze the bag as this will produce a cloudy jelly which will spoil the appearance of the preserve.
4. Place a couple of saucers in a cold fridge or freezer (these will be used for testing for a set of the jelly)
5. Measure the juice from the jelly.  Add 500g of sugar to every 600ml of juice. Bring to the boil stirring occasionally until all the sugar has dissolved. Then simmer until you reach 105 degrees C on a jam thermometer.  The time taken varies per batch. Whilst the jelly is simmering switch on the oven at Gas Mark 6/200 degrees C and sterilise your jars for about 6 minutes.  The jars should be warm when you fill them.
6. Skim off any scum as this spoils the visual asthetics of the jelly or jam. Some preserves produce a scum, this can be skimmed off with a ladle, but I usually add a knob of butter when the jelly comes to the boil as this helps stop the scum forming.  Test for a set by bringing one of the saucers out of the fridge/freezer and placing a spoon of the jelly on it.  Put back into the fridge or freezer for about 6 minutes.  If the sample sets i.e. looks jellied and forms a skin when you put a finger through the sample and does not rejoin up the preserve is ready for bottling if it is still watery it needs further cooking until the set is achieved.
7. Fill the warmed jars and cover with a waxed paper seal.  Put on new screw top lids. Store in a cool place.