Mouldy jam results from damp fruit, insufficient boiling, poor storage, badly-filled or covered jars.
Crystallized jam indicates too much sugar in proportion to fruit or over-cooking jam to stiffen it when too little sugar has been used. Over-cooking and poor stirring resulting in undissolved sugar can also cause the problem.
Fermenting, ‘winey’ jam results from over-ripe fruit, insufficient sugar or boiling, poor covering and bad storage.
Hard, dry jam results from over-boiling or bad covering when jam is stored in a warm place. Plastic or screwtops will help to prevent this problem.
Syrupy jam or jelly results from lack of pectin, from insufficient boiling or over-boiling past setting point. Jelly can be affected if strained fruit juice is left too long before cooking.
Poor flavour results from over- or under-ripe fruit, too much sugar, too slow boiling or over-boiling.
Poor colour results from poor quality fruit, from a poor quality preserving pan, or from storing in a bright light. It can also arise if the fruit is not cooked slowly enough to soften it completely, if the jam is over-boiled, or boiled too slowly to setting point.
Cloudy jelly results from poorly strained juice through a bag which is too thin, or if pulp is forced through the bag instead of letting the jelly drip by itself.
© 1978 Mary Norwak estate. All rights reserved.