Jam Cooking Method
There is science to jam making. The science of precise amounts of ingredients combining and reacting with each other to create a perfectly set jam.
Unfortunately, jam making is never precise. Even the same fruit plant, bush, or tree will give fruit with different levels of sweetness, juiciness, and pectin levels depending upon the time of year and the weather. The good news is that jam will always taste delicious - even if it is not perfectly set. Some people think that shop bought jam is often too set and stiff.
The experienced jam maker acquires the skill of knowing how to adjust cooking times and added ingredients (like pectin and lemon juice) according to the consistency they prefer in their jam.
How To Make Jam - Step By Step Approach
Nearly all jams follow the process described below:
1. Prepare The Fruit
This is an important and time consuming task. Only the best fruit at full ripeness, or just before, should be selected. The fruit needs to be prepared ready for eating, which means clean, with the stalks or husks removed, insect and bug free, and chopped coarsely.
2. Prepare The Jars And Lids
Many people re-use old jars and screw lids. All should be thoroughly cleaned in hot soapy water and rinsed. See jam jars available on Amazon UK.
3. Sterilise The Jars And Lids
It is important that the jars and lids are hot when being filled with the jam. This is to ensure they are sterile, but also to help create a good air tight seal when the lids are closed. I find the easiest way of sterilising the jars is to place them in an oven for 30 mins at 1000C. If the jam is not ready after this time, the jars can be left in the oven where they will remain hot. The process for lids is even easier. Place them loose in a pan of boiling water for 5 minutes.
4. Cook The Fruit
The fruit (and fruit acid) should be placed in a large flat bottom pan and heated over a medium heat. This process releases the all important pectin, softens the fruit, and enables the mixture to be gently mashed. Actual simmering times vary per recipe, with some jams avoiding boiling altogether and others requiring simmering for 30 minutes or so. Any froth or foam that forms on the surface of the cooking fruit can be removed carefully with a spoon or similar implement.
5. For Currants - Strain (Optional Step)
Blackcurrants, redcurrants, and whitecurrants contain a lot of skin and pips for the amount of juice. Straining the cooked fruit through a sieve, or muslin, is an excellent way of removing the problem. The collected juice can then be used to make the jam (actually a jelly). See muslin and strainers on Amazon UK.
6. Add Sugar / Pectin & Cook Further
Combine all the sugar and any pectin with the hot cooked fruit. Return the mixture to a vigorous boil and simmer for the time indicated in the recipe. Stir constantly to avoid the fruit sticking to the pan.
7. Judging The Jam Is Ready For Setting
If you intend to make jam regularly, a jam thermometer can be a useful investment. This measures the temperature of the jam and will tell you when the jam is ready for jarring. The jam setting point is when the mixture reaches 105oC. See jam thermometers on Amazon UK.
Without a jam thermometer, it can be tricky to know when the jam has cooked sufficiently to set, as you will only see the result once the jam has cooled down. Apart from following the exact cooking time, an experienced cook can also tell by the consistency of the mixture. If the jam falls off a spoon in blobs -rather than drips - it may be set. Alternatively, a useful trick is to chill a plate in the freezer or fridge. At the end of the cooking time a small amount of jam is placed on the cold plate. By using a finger or spoon, spread the jam across the plate, and if the jam skins at all it is ready to be jarred. Otherwise, the fruit mixture will need to simmer for a little longer.
As soon as the jam is ready it should be decanted into the prepared jars, leaving an air gap of around 1.5 cm before the top of the jar. The screw lids should be tightened immediately. Tea towels or kitchen gloves are extremely useful at this point as the jam, the jars, and the lids are all very hot. Any spills around the jar openings and threads should be completely removed with a clean cloth or tissue - to ensure nothing stops the lids being tightened all the way.
As the air trapped in the jam jars cools, the lids literally make a popping sound. This sound is made as the air pressure inside the jar forces the surface of the lids to be sucked downwards. This process usually takes a few minutes. When you push on the top centre of the lid with your finger, you should not be able to push the lid further down, nor should it spring back up. The popping sound or lid finger test demonstrates an air tight seal. Jars with an air tight seal can be stored in a cupboard for around a year (but check before eating that the seal is still good, and for any signs of mold or strange smells). Jams without an air tight seal should be stored in the fridge and eaten within a month.
After all the hard work making your jam, you may want to show it off, or even give some as gifts to friends and family. See our range of jam jar covers and jam labels.
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