JAM RULES!

Rules is rules when it comes to jam:

1. Prepare everything in advance. Jam making happens fast and good jam is all in the preparation.
2. Use your best heavy bottomed pan if you do not have a  jam pan.  You must allow for evaporation and foaming up.  Do not crowd the pan. The jam ingredients should only half fill the pan
3. Make jam in small quantities. Its what my Nana taught me and she was right. (there is in fact a scientific reason for this to do with boiling and surface area and evapouraton prior to setting)
4. Bacteria love jam.  You must be scrupulously clean and sterilise stuff.  Wash all jars and equipment for stirring/skimming/jarring in a solution of bicarbonate of soda
5. Set jams are traditional in the UK and France where there is much angst over it! Setting is a chemical reaction between sugar and pectin which results in jellification and occurs at 105C.  Fruits vary in pectin levels. Ripeness affects pectin too. Residual water content also affects the soft or hard set.  In Turkey, Romania and other Balkan countries jam is boiled just until the water is driven out – resulting in fresher tasting “soft set” jams. 
6. I test for setting by placing jam on a saucer placed in the freezer. when it doesn’t run when vertical or “wrinkles” when pushed it is set. This is the one time in life when wrinkles are a good thing. If I am in doubt I use a sugar thermometer. To be sure I take my jam to between 106-108C. When I don’t have any equipment I use my eyes and ears: the bubbles change size, the noise of the jam boiling changes and the appearance becomes “glassy”.
7. I increase pectin levels by making apple juice and apple puree from under ripe apples and adding this to jams. That way I dont need to add any extra pectin except when making no added sugar jam.
8. Pour jam into clean jars heated to 100C –  I do use a proper stainless steel jam filler but a ladle is fine if you have good hand to eye co-ordination (I don’t). If you have a super-duper dishwasher and are well timed you can set it at its hottest setting and wizz your too hot to handle jars out of the dishwasher straight to be filled.
9. Fill to the shoulders of the jar, screw the cap on fast, invert and let the 100C- plus jam sterilise that air gap and kill off any bacteria. North Americans and central Europeans like water bathing jams; I do too for low sugar and/or low acidity jams. Put them in a big pan of water with a folded tea towel inside the pan and boil gently up for 20 minutes or use a water bath.