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    Jam-making tips Easy Food

    Whether you are buying fruit or growing it yourself, it’s so readily available at this time of year that it’s the ideal time to brush up on your jam-making skills. Jam-making seems like a daunting task, but don’t be afraid – it’s relatively quick and easy, and it’s very satisfying to smell fresh jam being made and spread it over homemade scones or bread.

    Jam-making is the process of preserving fruit by using very high temperatures to soften the fruit and to kill microbes and enzymes. A high proportion of sugar (up to 65%) acts as a natural preservative and helps the jam to set. Essential to the setting process are also the correct proportions of acid and pectin.

    Key ingredients

    1. Fruit – Use high-quality, fresh, ripe and acidic fruit with a high proportion of pectin.
    2. Sugar – Sugar should be measured accurately as it is important for both sweetness and setting ability, and also acts as a preservative. Sure-set or jam sugar has a coating of pectin and acid on each large sugar crystal, resulting in a shorter boiling time and ensuring that the jam will set fully. Sure-set sugar is also more pure than granulated sugar and will produce less scum on top of the jam during boiling.
    3. Acid – This is needed in order to draw the pectin out from the fruit. Many fruits are naturally acidic, and so no extra acid may be needed, while some recipes include lemon juice to increase the acidity. Acid also helps to produce a better colour and flavour and prevent crystallisation.
    4. Pectin – Pectin is a polysaccharide found in the cell walls of ripe fruit and helps the jam to set. Some fruits contain more pectin than others and a combination of fruits can be used in order to achieve a good set.

    Pectin Content













    Key equipment

    • A large saucepan – This should be heavy-based so the jam does not easily stick and burn. A wide saucepan with low sides is most ideal as it helps speed up the evaporation process.
    • A sugar thermometer (optional) – This is the most accurate, failsafe way to test when the jam has reached setting point, but there are alternative methods
    • A jam funnel – This is very useful for pouring hot jam into jars, avoiding drips and burns.
    • Jam jars – These are essential for storing your jam and must be sterilised before use.
    • Jam jar covers – These are easily available in supermarkets during the summer months.

    Top tips

    1. Ensure you weigh everything accurately.
    2. Ensure the jars are washed and sterilised in the oven. Leave in the oven at a low temperature while you are making the jam, so that the glass is warm and will not crack when the hot jam is poured into it.
    3. Before adding the sugar, pre-warm it in a low oven: this will allow it to dissolve into the jam much more quickly.
    4. Ensure all of the sugar has dissolved before bringing the jam to the boil. This can be checked by rubbing the back of a metal spoon with some jam mixture on it against the side of the saucepan – listen and feel for any granules still present.
    5. When the sugar has fully dissolved, boil the jam rapidly until the setting point has been reached, only stirring occasionally.
    6. Skim off any scum before potting the jam. Ensure there are no drips around the neck of the jar, as these will prevent a seal being formed and encourage the growth of mould.
    7. Cover the jam immediately with waxed discs (wax side-down) and remove any air bubbles. Dampen the cellophane discs, stretch over the top of the jar and seal with an elastic band. As the jam cools, a vacuum will be created, pulling the cellophane even tighter and creating a complete seal.
    8. Label the jam and store in a dry, dark, well-ventilated area.

    How do I know when my jam has reached setting point?

    1 The jam will reach 105˚C on a sugar thermometer.

    2 The wrinkle test. Put a plate in the fridge until it is very cold. To check if the jam has reached setting point, put a teaspoon of jam on the plate and let it cool for 1-2 minutes, then push the jam with your finger. If the jam wrinkles, it has reached setting point.



    What went wrong

    Jam is not set

    Too runny or watery

    1. Not enough acid, sugar or pectin present.

    2. Did not reach setting point before it was potted.

    Fermentation of jam

    Mould growth; jam has an ‘off’ flavour

    1. Not enough sugar. 2. Poor quality fruit. 3. Not boiled long enough.


    Crystals of sugar in the jam

    1. Too much sugar. 2. Sugar was not fully dissolved before boiling.

    3. Not boiled for long enough. 4. Not enough acid.


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