Rhubarb jam is really easy to make and the preserved ginger adds a fabulous kick. We don't eat a lot of jam now and this quantity will make about 4 standard jars. The book was first published in 1974 and I'm afraid the quantities are in imperial meaures (pounds and ounces) but I've found a nifty conversion chart here if you want to use metric measurements.
Note: you need to start this recipe the night before you want to make the jam
Rhubarb and Ginger Jam2 1/2 lb prepared rhubarb
2 1/2 lb sugar
1 oz bruised root ginger (give it a good bash with a rolling pin!)
4oz preserved ginger (that's the kind in syrup)
Wash and trim the rhubarb and cut into 2in sticks. Weigh the fruit. Put alternate layers of fruit and sugar in a bowl, cover and leave to stand overnight.
In the morning most of the sugar will have dissolved and the juices will have come out of the rhubarb.
Turn into a pan, add the root ginger tied in a piece of muslin and bring slowly to the boil. Fast boil for 15 minutes. Remove the ginger and add the preserved ginger, boil for a further 5 minutes. By this time the rhubarb should be clear. Test for set. Pot and cover in the usual way.
If you have never made jam before, read this excellent article, published in the Guardian Lifestyle, by Darina Allen which should answer any questions you have. But really, it's not that difficult, you don't need sugar thermometers or liquid pectin, my mother and grandmother never used them. A cold saucer in the fridge, a teaspoonful of jam, let it cool, then push with your finger and if there is a 'skin' then it is set, if not boil for another 5 minutes and try again.