Jam making
Jam is prepared by boiling fruit witha sugar solution until it forms a gel which sets on cooling.
In order for a gel to form, the jam should contain:
Pectin
Acid
Sugar
and it is important that these are present in the right concentration.
Pectin
Pectin is a polysaccharide. During jam making its molecule form a three dimensional network with the water, sugar, solid matter from the fruit.
Pectin will not form a satisfactory gel until the PH of the mixture is about 3.5.
It is found in the cell walls of fruits and vegetables. The amount present depends on the type of food and its age. Unripe fruit contains more acid and pectin. Overripe fruit contains pectin which has been converted into a form which is unable to form a gel.
Acid
Acid is needed to extract the pectin from the fruit during stewing, and fruits that have a high pectin content are normally acidic. Acids also improves the color and flavour of the jam and prevents the sugar from forming crystals during storage.
Sugar
Sugar is added as a preservative and to form the gel. It must be accurately measured, as too much will cause crystallization of the sugar, and too little will prevent proper setting and will encourage fermentation to take place. The sugar should be about 60% of the total finished weight of the jam.
Preserving sugar is specially made for this purpose. It is composed of large crystals which are purer than oridinary granulated sugar, and so cause less scum to form during boiling. Some brands have added pectin. Granulated sugar is an acceptable alternative, however and is cheaper.
Choice of fruit
The fruit used for jam making should be
Slightly under ripe
Free from blemishes and mould growth clean
Fruits rich in pectin
Cooking apples
Lemons
Redcurrants
Gooseberries
Blackcurrants
Fruits with a good pectin content
Blackberries
Plums
Apricots
Raspberries
Fruits with a poor pectin content
Stawberries
Cherries
Pears
In order to make a successful jam from fruits with proper pectin content, other fruits that are rich in pectin can be added orHow are commercially prepared pectin concentrate can be used.
Equipment required for jam making
PAN
A lareg thick based pan should be used to allow space for the boiling mixture to rise, and tpo prevent the jam from burning on the base. Special preserving pans are most suitable, and they normally have a large handle and lip for easy pouring.
WOODEN SPOON
Wooden spoon with a long handle for easy stirring.
JARS
Empty, used jars are suitable providing that they have no cracks or chips in them. They must be well cleaned, and warmed in the oven before use, so that they do not crack when the hot jam is put into them.
MEASURING JUGS
A heat proof jug should be used for transferring the jams to the jars.
JAM JARS COVERS
Jam jars covers can be bought in different sizes and consist of:
1. Small waxed circles of paper, which are placed, waxed side down, on to the hot jams. The wax melts and forms an airtight seal over the jam to prevent Mould growth.
2. Large cellophanes circles which fit over the neck of the jar and are kept in place with a rubber band. They are placed over the jar while the jam is hot, and on cooling, they shrink to form a second seal over the jam.
EQUIPMENT TO TEST FOR SETTING
A sugar thermometer
a cold plate
saucer
EQUIPMENT TO TEST FOR PECTIN
two glasses
methylated spirits
LABELS
Sels adhesive labels are best and should indicate the content of the jar and the date of preparation.
METHOD
1. Wash the fruit and remove bruised over ripped pieces. Dry it.
2. Prepare the fruit:
remove stalks and leaves
remove stones or cores
chop the fruit as required
The stones of plums, apricots can be included while the fruit is being stewed as they usually have some pectin in and around them. They should be removed at the end of the stewing process.
3. Grease the preserving pan with margarine or butter to prevent the fruit from sticking and to reduce the amount of scum produced when the jam is boiled.
4. Add the water to the fruit and simmer until the fruit is very tender. This stage is important as the pectin is extracted from the fruit with the help of acid which is either added or is already present in the fruit. Fruits that are rich in pectin have water added to soften them properly, and to prevent the jam from setting to hard because of the high pectin content. Fruits that have a poor pectin content have lemon juice added to assist the extraction of the pectin that is present. The amount of time required for stewing at this stage varies.
5. After stewing the fruit, test is for pectin. Cool some of the fruit and juice for a few minutes, in a glass. Add three parts methylated spirit to one part of the fruit liquid and leave for one minute. Gently pour this into another glass and observes its consistency.
6. If the pectin content is poor, the fruit may be stewed for longer, and retested, or fruit with a high pectin content can be added, but this must have stewed separately first.
7. Whilst the fruit is stewing, wash the jars well and warm them in the oven so that they are completely dry and ready to take the hot jam.
8. Add the sugar all at once. It can be prewarmed in the oven to make it dissolve more quickly. Stir it over a gentle heat until dissolved. If the sugar is added before the fruit has been sufficiently stewed and softened, it will cause the skin to become too tough.
9. Bring the mixture to the boil quickly, a stir it occasionally. Bol rapidly to each setting point quickly, and thus prevent the spoilage of flavor and color by overcooking. Remove any scums that appear on the surface with a draining spoon. When testing for setting point, remove the pan from the heat to prevent overcooking, which will result in a hard jam.
10. When setting point is reached, pour into the hot jars, fill to the tops, seal and cover while still hot, and leave the jam to cool and set at room temperature. Label when cool, wiping the jars if necessary.
QUALITIES OF A GOOD JAM
Well-made jam should have the following qualities:
a good flavor
a bright color
a clear appearance
evenly distributed fruit
a firm, but easy to spread texture
STORING JAM
Jam should be stored in a cool, dry and dark place. Screws on lids can be used as an extra seal. If the jam is stored in warm, moist conditions, the growth of Mould should be encouraged.
FAULTS IN JAM MAKING
Jam has crystalized
CAUSES
1. Insufficient boiling of jam
2. Overcooking of jam
3. Too much sugar used
4. Insufficient acid in the mixture
Jam has Mould growing on top
CAUSES
1. Incorrect storage
2. Poor quality fruit was used
3. Insufficient sugar used
4. Incorrect filling od jars and sealing
Fruit is tough
CAUSES
1. Insufficient stewing
2. Sugar added too soon
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