There’s something deeply satisfying about making blackberry jam. It might be that (for me) it’s one of the last truly seasonal foods, so it reminds me of those long ago summers when my lovely Nan used to send us out blackberrying for tarts and crumbles. Back in the 70’s when all summers were wall to wall sunshine and not a drop of rain fell. Well, not in my memories anyway!
Making jam is so easy, and so straightforward that it seems a shame not to make at least one batch. There really isn’t anything to it, and it only takes 20 – 30 minutes from start to finish. The recipe and method below applies to all fruits, those very low in pectin (strawberries and apricots) benefit from the addition of the juice of a lemon.
Prepare by sterilising your jars, I use Milton baby bottle sterilising fluid, and pop a few small plates or saucers in the freezer.
While the jars are sterilising prepare your fruit – the blackberries will have ideally had a good long soak in salt water to draw out any ‘visitors’ and then been rinsed very well to make sure the salt is washed off.
I have found that the actual quantity of jam produced differs according to the fruit used, but 700g of fruit will usually yield somewhere between 3-4 250ml jars of jam. I sterilise 6 just to be on the safe side.
For every 100g of fruit you use, you need 100g of jam (or preserving) sugar. The bags are very helpful and tell you which fruits they are best suited to. I usually use jam sugar.
Pop your rinsed fruit into a pan with the sugar and a drop of water (about a tablespoon or so) and heat slowly until the sugar has dissolved, stirring fairly frequently – you can see when the sugar has dissolved on the back of your wooden spoon and around the sides of the pan. Once all the sugar has dissolved bring the contents of the pan up to a full rolling boil and time it for 10 minutes, stirring from time to time to stop it catching. Some jams will come to a ‘set’ quicker than others, those with high pectin set much sooner than low pectin fruits. You will quickly learn when they are approaching setting point as the juices on the back of your wooden spoon thicken.
To test for a set take the plates out of the freezer and drop a small amount of jam on one, leave it for a few moments and then push with your little finger, it will wrinkle when it is ready. Then turn out the heat and leave the jam to settle for a few moments while you assemble your jars and funnel ready for filling.
Once filled, tighten the lids of the jars straight away and leave until cool before labelling.