Making jam - a universal recipe
A Universal Recipe
This is how I make jam, but you can equally cut the fruit up and macerate it with the sugar overnight - this will give you a quicker cooking time the day after. If doing so, Stage 1 will happen very quickly.
Taste your fruit and assess its sweetness, and work out your ratio of sugar. I generally use between 26 -30%. If the fruit is sweet, I start at the lower amount.4kg fruit (if using stone fruit washed and weighed with the stone removed. There is no need to dry the fruit, a little bit of water is good.) 1.2kg raw sugar 1 medium sized lemon, skin on, cut into 8 bits
Sterilise all jars and lids, place them on a baking tray lined with a clean tea towel and keep warm in a low oven.
Cut the fruit into desired portions into smaller portions. Discard any seed (as in apricots etc). As a general guide, leave blueberries and small strawberries whole, but chop larger strawberries; cut apricots and plums into halves or quarters; cut figs into quarters or smaller segments.
Put the fruit in your jam pot, together with sugar and lemon. Gently stir the sugar through.
Place the pot over a very low heat, allowing the sugar to dissolve. This takes about 15 minutes, or a bit longer, depending on the size of your pot. Stir gently and rarely.
Once the sugar is visibly starting to dissolve, increase the heat slightly until you see a gentle bubbling. Stir frequently. Continue to cook for 15 mins (or longer if using a deeper pot). The juices will have wept out from the fruit, thus increasing the amount of liquid in the pot.
Increase the heat to a very high boil until a “set” is achieved. As you are now cooking at a high boil, you need to stir frequently to check the feel of the jam and to make sure it isn't sticking to the bottom (a long sleeved shirt is good here). As the jam reduces, it will thicken. You may need to reduce the heat to a slower boil as the jam thickens, but keep stirring frequently. This stage should take about 30 minutes, but the deeper the pot, the longer it will take. It should take about 10 minutes if using a small 1kg amount.
Set is generally considered to occur when the jam reaches 105 degrees C (for a 60% sugar jam). But this doesn't hold for low sugar jams, where the relationship between sugar, acid and pectin has been disrupted. I go by appearance and “feel” and cook the jam until it is fairly thick. The bubbles also become more volcanic and flat. Placing a small amount of jam on a saucer or dish and chilling it is another good method for checking the constancy. When cool, run your finger through the middle - you want to see a clear line of plate underneath. Any juices that flow into the line should look like lovely liquid jam, and not at all watery, and should have body.
The jam must be ladled into the warm jars immediately; it's incredibly important that the jam goes into the jars very, very hot, as this will create the vacuum seal on the jars. Make sure the jars are not on a cold surface - keeping them on the warm tray is a good idea. Fill the jars (to within just over 1/2 cm of the top rim - a smaller air space will create a faster and better vacuum) and remove (with a clean, damp cloth) any jam around the edge or lip of the jar, as this will interfere with a good seal forming. Seal the lid and leave to sit (though you can move them to a cooling rack gently) until absolutely cool. When cool, check for a concave dent in the lid. If there isn't one, store the jam in the fridge and use.
Read Jude’s general tips for jam making in our January issue online (click on the magazine cover)