JAM MAKING – The Basics:

THE FRUIT
The fruit should be as fresh as possible, if anything slightly under-ripe. In practice, a mixture of ripe and unripe fruit is often used and is quite satisfactory. Over-ripe fruit, however, never makes satisfactory jam since it will not set properly. The reason why fruit is capable of forming a “gel” or jelly when boiled with sugar is because it contains in its cell-walls a natural gum-like substance called “pectin”. When making jam the first object is to extract the pectin from the fruit, and it has been found, as a result of many tests, that this can be done most easily when the fruit is slight under-ripe.

Cooking apples, black and redcurrants, damsons, gooseberries and some plums are easy to convert into jam because they are rich in both pectin and acid. Fruits of medium setting quality for jam-making include apricots, blackberries, greengages, loganberries and raspberries. Fruits which are of poor setting quality include cherries, pears and some varieties of strawberries.

The fruit should generally be cooked gently for some time before the sugar is added. The object of such cooking is to soften the skins and to breakdown the cell-walls of the fruit and so extract the pectin. Sufficient water should be added to prevent the fruit from burning, but the amount needed will depend very much on the juiciness of the fruit, the amount of fruit in the pan and the source of heat. A shallow pan which allows quick evaporation needs more water than a deep one. When increasing the quantities in a recipe, less water is required in proportion, also the riper the fruit the less water is usually required for softening and cooking. The fruit should be brought to the boil and then allowed to simmer gently until it is reduced to a pulp. Blackcurrants, damsons or plums should be cooked for half or three-quarters of an hour, or until the fruit is broken down and the skins are thoroughly soft. All fruits which require added water should be boiled down by about one-third before the sugar is added.

Fruits which break down readily, e.g. raspberries and strawberries, do not require the addition of any water but strawberries may need simmering for 10-15 min. before the sugar is added.

SUGAR
Sugar plays an important part in jam-making, because the jam owes its keeping quality to it. Also a poor set will result if there is too much or too little sugar present, while the flavour of the product will be impaired by over-sweetening.

In home-made jams, the best combination of keeping quality, good set and good flavour, is usually obtained when 60 per cent of the final weight of the jam is provided by the sugar added. The jam will then contain rather more than this percentage of sugar on account of the presence of the natural sugars in the fruits.

Sugar may be heated before it is added to the fruit. This process is not essential, but it has the advantage that the sugar dissolves much more quickly when hot than when cold and does not cool the fruit so much, especially in jams that are boiled for a very short time. When the sugar has been added the jam should be stirred until all the sugar has been dissolved, and then the jam should be brought to boiling point as quickly as possible and allowed to boil rapidly. If the fruit has been well cooked before the addition of sugar, it should not afterwards be necessary to boil the jam for longer than 3-20 minutes according to its kind and quantity. Slow cooking before the addition of sugar and very rapid and short cooking afterwards is the golden rule for jam-making. If the sugar is added too soon, so that the fruit and sugar are boiled too long together, both the colour and flavour of the jam are spoilt and the probability of tough skins in the jam is increased.

ACID
If the fruit being used is one to which the addition of a little acid is necessary, this should be added before the fruit is cooked as it helps to extract the pectin. Fruits deficient in acid are strawberries, blackberries (if picked late in the season), pears and sweet varieties of apples and cherries. The following substances may be used to provide additional acid, and the quantities suggested are suitable for adding to 4 lbs (1.8K) of fruit: lemon juice: 2 tablespoons of juice (approximately 1 average-sized lemon, citric or tartaric acid: ½ level teaspoonful of either or redcurrant or gooseberry juice: ¼ pt.(142 mls.) of either.

PECTIN
Fruits (such as blackberries, cherries and marrows) lacking in pectin, may be made into satisfactory jam if pectin is added in one of the following ways:

1. Blending with fruit rich in pectin. Blackberry and apple, or marrow and damson are examples of mixed fruit jams in which the pectin, which may be lacking in the first fruit, is supplemented by that in the second.
2. Adding fruit juice rich in pectin. Most fruits that are deficient in pectin also lack sufficient acid, so the addition of fruit juice rich in both these constituents will have a beneficial effect in both ways. Lemon juice is rich in pectin as well as being very acid.
3. Adding commercial pectins. The use of such pectin is quite unnecessary in making jam from blackcurrants, gooseberries etc. But when difficulty is experienced with fruits such as strawberries, cherries and rhubarb, the addition of pectin can be of great use and give excellent results, provided the fruit is well softened before the sugar is added. For these fruits a suitable quantity is 2 to 4 oz liquid pectin or about ¼ oz powdered pectin to each pound of fruit. This will bring the pectin content of the fruit up to the average level of good jam fruits. The flavour of the jam can be ruined by the addition of too much pectin.

THE PECTIN TEST
There is a simple test to check the pectin content of the fruit pulp after simmering but before you add the sugar. This will tell you whether more pectin is required or whether you need to cook for a little longer to extract more pectin. Take a teaspoon of juice from the pan, pour into a small glass container and allow it to cool. Add a tablespoon of methylated spirit to the cooled juice and shake well. After a minute or so a transparent clot should form. If the clot is large and jelly-like, the pectin content is high. No additional pectin is required. If the clot is in two or three lumps, the pectin content is medium, but adequate for a set. If there is no clot, or if there are lots of very small ones, the pectin content is low and extra pectin is needed.
 
PECTIN STOCK
Instead of throwing away the peel, core and pips when preparing apples for chutney etc make your own pectin stock. It can also be made from green gooseberries and redcurrants. Cover with water and cook gently for 45 minutes to an hour. Use a jelly bag and allow the contents of the pan to drip through – the resulting liquid will be virtually tasteless pectin stock. You can test it to make sure you have a good pectin level and freeze in ½ pint containers. This is now ready to add to any jam needing pectin and will keep the true taste of the fruit being used. Pectin can also be bought commercially.

SETTING POINT
If a little of the jam is cooled on a plate, the surface should set and crinkle when pushed with the finger. The jam should not be allowed to boil rapidly whilst this test is being made, If a little of the jam is cooled on a plate, the surface otherwise the setting point may be missed.

JARS
Most jam makers would use jam jars in various shapes and sizes. Sizes on the website range from 1.9 oz (55ml ) up to 2lb. (725ml). They are sold in plain, hexagonal, octagonal and other shapes. Twist off heat sealable lids are available for all. Clip Top jars and kilner style jars are more often used for bottling.

STERILISING JARS
It is very important to sterilise jars. When using old jars always check for any cracks or chips before washing the jars to remove any old labels etc. You will find sticky label remover on the website. Rinse the jars well in very hot water and turn upside down to drain. Place on a cooling rack on a pad of kitchen paper and place in the oven at a temperature of 160 degrees C or 325 degrees F Gas Mark 3 for ten minutes or until completely dry. Leave to cool before filling. Or the jars can be placed in a deep pan covered with water. Bring to the boil for ten minutes and carefully remove and allow to drain and dry.

FILLING THE JARS
Jars of any shape or size need to thoroughly clean, dry and preferably hot. Once the setting point is reached take the pan from the heat and fill the jars. Use a stainless steel jam funnel for this task (available on the website) which avoids soiling the jars and saves dripping etc. It is important to fill the jars virtually to the top because shrinkage after cooling will lower the level by ½ cm or so.

COVERING
As soon as each jar is filled, place a waxed circle or disc (waxed side down) onto the hot surface of the jam so that it is flat on the jam surface excluding air beneath it. The disc must be flush with the sides of the jar. The best results are obtained by sealing airtight immediately as each very hot jar is filled. A wooden board is good as this is a poor conductor of heat and the jars will remain hot for longer. Twist tops effect a quick and definite seal and do not need a wax disc on top of the jam. If twist tops are not available cellophane circles can be pressed down over the top of the jar and held in place with either string or rubber band (sets of these are available on the website in two sizes).

Chutneys also require a waxed disc, and pickles must have a good plastic-coated airtight lid not just to keep the bacteria out but to stop the vinegar evaporating. (All aforementioned lids available on the website). For that special touch attractive material or paper covers are available on the website turning your produce into an attractive gift. For those preservers who own old kilner jars the website provides the answer. The Leifheit kilner style jar spare sealing discs fit all old English kilner jars manufactured since 1948. Simply replace the old glass disc, or metal sealing disc with the Leifheit discs sold in boxes of 12. They have an integral rubber sealing ring so there is no need for separate sealing rings. Unfortunately the screw rings are not compatible with old English kilner jars.

LABELS
It is a very good idea to label produce especially with the date of making and name of the jam. Various designs are available on the website.

STORAGE
The key to successful and long storage of preserves is a cool, dark place away from direct sunlight. Choose a kitchen cupboard well away from the boiler, cooker or window, or use the cupboard under the stairs. If the storage place is too warm then the jam will shrink, too light and the colour will fade, and any damp will make the preserve mouldy.

JAM MAKING RULES
1. A syrupy or runny jam may be due to underboiling, to a deficiency of pectin or acid, or to the use of too high a proportion of sugar.
2. Jam ferments when underboiled or when there is a deficiency of sugar.
3. Scum should never be removed until the jam is made. Continuous skimming is wasteful and unnecessary.
4. If screw-top jam jars are used, the metal covers should be scrupulously clean and should be placed on the jars immediately the jam has been poured in.
5. The jam should be stored in a dry, dark, cool cupboard.
6. Overboiling the sugar darkens the colour and spoils the fresh fruit flavour and may cause a “sticky” jam.

EQUIPMENT
Jam Pan
Brass and copper preserving pans were once considered to be the best for jam making but now knowledge has shown that stainless steel pans are better.
It is a mistake to try to make too much jam at once. To allow room for the jam to boil vigorously, the pan should only be about half full when the sugar has been added. A small piece of butter or margarine rubbed over the bottom of the pan helps to avoid scum and prevents the pulp from sticking. Choose a pan with a thick base to reduce the chances of the jam burning. (Stainless steel jam pan available on the Preserving Section of the website).

Thermometer
A quick look at a thermometer will ascertain when jams are coming up to setting point.

Jelly Bag
When making jellies a jelly bag is required either nylon or the traditional white cotton flannel. Both kinds work in the same way. First hang the bag above a bowl so that the bottom of the bag is just above the bowl. (A bag complete with bowl stand is sold by Wares if required). Scald the bowl
w ith boiling water and fill the bag with the cooked fruit and liquid leaving undisturbed for 3 – 4 hours. Do not squeeze the bag or the juice will cloud. Wash the bag well in boiling water do not use detergent.

Wooden Spoons
A long handled wooden spoon is required for stirring and a stainless steel spoon with holes in recommended to remove any scum.(A set of wooden spoons is available on the website).

Funnels
A jam funnel reduces spills down the sides of jars and makes filling jars safer. Stainless steel will withstand the high temperatures required. For filling bottles etc. a small plastic funnel is ideal. (You will find both on the website).

Jars and Bottles
Jam jars in all shapes and sizes available on the website for jams, jellies, marmalades etc. Oil bottles for cordials etc. Bottling requires purpose-made bottling jars with rubber rings such as the clip top jars sold on the website. Kilner style jars by both Leifhet and Mason Ball are also available. For those preservers who own old kilnerj ars the website provides the answer where new sealing discs are concerned. The Leifheit kilner style jar spare sealing discs fit all old English kilnerjars manufactured since 1948. Simply replace the old glass disc, or metal sealing disc with the Leifheit discs sold in boxes of 12. The discs have an integral rubber sealing ring so there is no need for separate sealing band. Unfortunately the screw bands are not compatible with old English kilner jars.