Jam Sugar (equal weights of sugar and fruit)
Pectin (I use sugar with added apple pectin for low-pectin fruits such as strawberries.)
Pan, surprisingly large
Jars with correctly fitting lids, many
Long Wooden Spoon
Heat resistant jug with spout
Sticky labels and good pen
Thermometer. Optional, but highly recommended
Waxy paper discs. Optional, but useful if showing off
Prepare the jars
If you care about the environment, you’ll be reusing jars that you and your friends have collected. You probably don’t want your strawberry jam smelling of picalilli or going mouldy, so you need to make sure that your jars and especially the lids are very clean. I do this by soaking the jars and lids in very very hot soapy water, then making with a fresh washing up sponge and scrubbing brush. Rinse them out (soap flavoured jam is uncommon for a reason).
You need to at least make an attempt to sterilise the jars. Some people have complicated and expensive ways of doing this, I put them in the fan oven at about 100 Degrees C. Any hotter and you’ll melt the lids (melted-plastic flavoured jam is also uncommon). My thermometer suggests anything hotter than 85 Degrees C will suffice, but I’m not a microbiologist so am not qualified to make any promises.
Prepare the fruit
Wash and edit the fruit for any bits you don’t like the look of (greenfly jam is uncommon).We’re dealing with large soft fruit that’s got a lot of water locked up in it, so just put all the fruit into your preserving pan and heat it up gently. Stir frequently. Within about 10-15 minutes it will be bubbling away.
Make the syrup
Once the fruit is fluid, add the sugar. It will look like you’ve added really far too much sugar, but just keep stirring and stirring, eventually it will melt, dissolve and incoporate into the fruit. When you have a smooth syrup, you need to boil it to release and activate the pectin.
Set the jam
Stir now, stir often (burnt jam is bad, tastes horrible and makes a mess of the pan).
Boil the jam until “set point” is reached. It is entirely possible to judge set point by eye alone, but it does take some practice and experience.
To dispel this black voodoo magic part of the process, here is how easy it is for beginners:
Jam boils at 105 Degrees C. this is where the thermometer helps. When it’s boiled for 5-7 minutes (keep stirring), you should have reduced the volume of the syrup such that it will form a skin within 30 seconds if a teaspoons worth is dropped onto a room temperature plate.
If you’re keen to minimise the risk of the jam going off prematurely, go go go! If you’d rather have the bits of fruit properly mixed in, leave the jam to cool for 20 minutes then give it a good stir.
Take your hot jars out of the hot oven and put them on a work surface. I use a 2″ thick wooden chopping board because my landlord wouldn’t like me setting fire to the kitchen worktop.
Use a ladle to transfer the jam from the pan to the jug. Try not to spill it, jam makes a sticky mess. Accurately pour the jam into the jars. You want to leave the jar necks empty but fill up the shoulders of the jar.
Top the jam with a waxed paper disc.Screw on the lids properly.
Wait for the jam to cool in the jars.
This typically takes over night and is characterised by the popping of the safety buttons in the lids as the cooling jam causes the little air left in the jars to contract, forming a slight vaccuum. Write the labels with what’s it is and the date and stick them on. You waited for the jar to cool or you’d have melted the glue and made a sticky mess.
Homemade jam can last over 2 years if kept in a cool dark space. Mine typically doesn’t last the year because my family and friends are rather partial to the stuff 🙂