Basic Jam Ingredients

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There are 4 key ingredients required when making jams, jellies or marmalades to achieve the perfect set. Understanding how these affect the end result will help ensure success – especially if you have some unusual fruits and do not have a recipe to follow.

Fruit

Fruit is best picked on a dry sunny day, and ideally when very slightly under ripe. Fruit contains the maximum amount of pectin before it ripens and pectin is essential in achieving a good set. Fruit that is over-ripe contains less pectin and acid (also essential) and the fruit will be soft and mushy producing a poor jam as a result. If you don’t have time to make jam immediately when the fruit is ready to be picked, then it can easily be frozen and made into jam at a later date.

Pectin

This is naturally present in most fruits (and some vegetables), although the pectin content can vary greatly. Pectin is concentrated in the skins, cores, pith, and pips of fruit. It is a glue like ingredient that is found in cell walls and is extracted by cooking assisted by the presence of acid.

Some fruits contain high amounts of pectin and will set very easily, others may require the addition of powdered or bottled pectin (or use sugar with pectin already added) to achieve a goo set. Alternatively you could mix 2 different fruits to achieve the right pectin content – apples are very high in pectin and are a great addition to many jellies (blackberry and apple, herb jelly and so on).

The pectin content of many fruits are listed below, however there is also a simple test that can be carried out.

      1. Add 1tsp (5ml) of the cooked fruit juice to 1tbsp (15ml) alcohol (methylated spirit, gin, vodka, whisky…or any other spirit you have lying around), and shake gently.
      2. If the mixture forms a firm clot, then the fruit is high in pectin, if it forms several smaller clots then it has a medium pectin content, and if mostly liquid it has very low pectin content.

Acid

Acid is generally present in most fruits, and as with pectin levels some fruit contain more than others. Acid levels are higher in slightly under-ripe fruit. Add lemon juice to fruits low in acid before cooking the fruit to help extract the pectin. A good balance of acid will also help give the preserve a good colour and sparkle.

For fruits low in pectin add 30ml lemon juice to every kilogram of fruit.

Sugar

Not only does the sugar enhance the flavour of the jam, but it is the natural preservative that will keep the jam fresh. Boiling the fruit and sugar mixture drives away the water content, and it is this balance that achieves a great set. Getting the sugar balance is essential. Not enough and the jam will require a long boiling time to set, and the end result will be dark and overcooked – too much and the jam won’t set and will be sugary and syrupy.

Pectin and Acid Content

FRUIT

PECTIN

ACID

Apples (cooking)

High

High

Apples (Eating)

Medium

Low

Apricots

Medium

Low

Blackberries

Medium

Low

Blueberries

Medium

High

Cherries (sour)

Medium

High

Cherries (sweet)

Low

Low

Crab Apples

High

High

Cranberries

High

Medium

Currants (red, white & black)

High

High

Damsons

High

High

Elderberries

Low

Low

Figs

Low

Low

Gooseberries

High

High

Grapes

Low

Low

Greengages

High

High

Loganberries

Medium

High

Medlars

Low

Low

Melons

Low

Low

Mulberries

Medium

High

Nectarines

Low

Low

Oranges & citrus

High

High

Peaches

Low

Low

Pears

Low

Low

Plums

Medium

Medium

Quince

High

Low

Raspberries

Medium

Medium

Rhubarb

Low

Low

Rowan berries

Medium

High

Sloes

Medium

High

Strawberries

Low

Low

Phyl @ The Allotment Gardener

Lifelong gardener and allotment enthusiast. Now have 3 allotments!

Website: allotment.uk.com
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