Follow these four steps for almost every jam you make

  1. Choose your fruit. Wash & crush it
  2. Boil the fruit in a little plain water till soft
  3. When soft & cooked, add the sugar and pectin, mixed. Then add lemon juice or cream of tartar
  4. Boil rapidly to 104° C (220°F) and it will be ready. (about 20 minutes)

A generic jam recipe

1 kg cleaned crushed fruit 2.2lb + 125g water (1/2 cup)

1 kg sugar 2.2 lb

30 g lime juice, lemon juice (OR 2 tsp cream of tartar)

10 g pectin powder (2 tsp)


What is the difference between jam and jelly?

Jam is chunky fruit or thick fruit puree that has been ‘set’ by boiling with sugar. Jelly is a clear fruit juice that has been ‘set’ by boiling with sugar.

Why does jam set?

When fruit is boiled with water it collapses and any pectin in the fruit is released. When sugar and an acid (like lemon juice) is cooked with fruit it reacts with the pectin in the fruit to form a jel. Most jam fruits are high in pectin naturally. If using a fruit without lots of natural pectin, you have to add apple seeds, orange skins or pectin extract to get the same result

Why did my jam come out runny?

Undercooked (not at 104-105°C). Not enough pectin, not enough acid, or not enough sugar. The fruit does not gel easily (eg Pineapple)

Why is my jam too thick?

Overcooked, or too much pectin

What sort of pot do I need?

Bigger is better. Use a wide bottomed pot with a heavy bottom that has even heat distribution.

The 4 things you need to make jam

  1. Fruit
  2. Sugar
  3. Pectin
  4. Acid

About the fruit

Some fruits contain a lot of pectin and set into jam easily. Pectin is a natural substance. Apples and citrus fruit are very high in pectin. If the fruit you are using has a lot of pectin, you don’t need to add extra pectin. If the fruit you are using is low in pectin, you need to add pectin powder, OR add a high pectin fruit, like apple, apple seeds or citrus peel.

About the sugar

Jam is high in sugar. Expect an average quantity of around 50% fruit and 50% sugar. The sugar and acid preserves the fruit and provides texture. It IS possible to make low-sugar jam and sugar-free jam. Do a Google search for those recipes.

About the pectin

Pectin is a natural ‘polysaccharide’. When boiled with sugar, and an acid like lemon juice, it forms a ‘gel’. Many fruits contain a lot of pectin naturally. Fruit has more pectin when under-ripe and less when fully ripened. Powdered pectin extract is available commercially. These are made from orange and lemon skins, or apple seeds.

About the acid

Lemon juice, lime juice or cream of tartar (tartaric acid) are the usual options. Pectin needs to be cooked with sugar and acid to form a jam or gel.

A quick list of High Pectin Fruits:

  • Orange skin, lemon skin, grapefruit skin, lime skin.
  • Raspberries, gooseberries, blackberries, cranberries
  • Apples, grapes, plums

When using the high pectin fruits above, no added pectin is needed. They have enough naturally.

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