Preservation of food as sugar concentrates is one way of conserving fruits. It provides a way of utilising some of the produce that is not good enough to be used for bottling, canning or freezing.
Jams, jellies, marmalades and other preserves are much alike in that all of them are preserved using sugar and usually all are jellied to some extent.
Jam is made from crushed or ground fruit. It holds its shape but not as firmly as the jelly.
A jelly is made from fruit juice. The product is clear and firm and holds its shape when turned out of a container.
Marmalades are tender jellies with small pieces of fruit distributed evenly throughout the product.
They are usually made from citrus fruits like oranges, lemons, grapefruits and limes. Preserves are whole fruits or large pieces of fruit in thick syrup, which is slightly jellied.
Fruits: It gives the product its characteristic flavour. Fruits that are rich in flavour are best because the large proportions of sugar used sometimes dilutes the flavour.
Pectin: It is the gum-like substance in fruits, which causes the products to set and thicken. Some types of fruits have enough natural pectin and others require addition for better results, particularly when they are used for making jellies that should be firm enough to hold their shape.
Acid: It is needed to add flavour and the formation of gel. The acid content varies in different fruits and is higher in under ripe fruits. For fruits that are low in acid, lemon juice and citric acid are added.
Sugar: It helps in gel formation, serves as the preserving agent and contributes to flavour of the product. It also has a firming effect on the fruit; a property that is essential in the making of preserves.
You need a large saucepan or sufuria, measuring cup, spoons, steel knives, a wooden spoon, chopping board, a masher and kitchen scale. For jelly making, a jelly bag is required for extracting juice from the fruit.
Making jams and jellies
• Use firm and ripe or slightly under-ripe fruit.
• Use a saucepan that is large enough to allow frothing up when sugar is added.
• Simmer the fruit until it is soft and all the juice and pectin has been extracted. Use only enough water to start extraction.
• Add sugar slowly, stirring all the time and do not allow fast boiling before the sugar is completely dissolved.
• Boil rapidly after the sugar has dissolved until setting point is reached.
• Remove the scum when the jam or jelly is ready.
Testing the setting point
Two methods are used:
Dip the stirring spoon in the boiling jam/jelly mixture, then raise it at least 30cm above the pot. Hold the spoon horizontally for a few seconds, and then turn the spoon so that the jam/jelly runs off the side.
If it falls in clear drops, it is done. If the flow is continuous, it should be cooked a little longer.
Cold plate test
Pour a small amount of jam/jelly onto a cold plate or saucer. When quite cold, push it with the forefinger. The jam/jelly is ready if it forms wrinkles and a layer forms on it.
Mangoes, guavas, pineapples, plums, strawberries, pawpaw, bananas and tomatoes make good jams whereas apple, gooseberry, plums and guava are good fruit choices for jellies.
Ms Ndung’i is based at the Department of Human Nutrition, Egerton University.