Pectin

Pectin is a soluble fibre found in plant cell walls, especially in apples and citrus peel. Food makers extract and dry it into a gelling ingredient for jams, jellies and sweets.

Follow the proportions and order on the pectin packet: some types need sugar and acid, while others are formulated to set with less sugar. Usually you stir pectin into the fruit or sugar as directed, bring the mixture to a full boil, then boil it for the stated time; adding it late can leave lumps or a weak set.

Common causes are using the wrong pectin for the recipe, changing the sugar or acid, or not boiling for long enough. Let the jam cool completely before judging it; if it is still runny, reboil it with the matching pectin and the amount of acid or sugar its instructions specify.

Not reliably: gelatine sets as it cools and melts again when heated, while pectin can give jam a firm set at room temperature. For jam, use a pectin-free recipe designed around naturally pectin-rich fruit, or a tested alternative such as lemon juice and apple peel.

They are not usually interchangeable spoon for spoon: recipes give different amounts and add them at different stages. Powder is often mixed with sugar or fruit before boiling, while liquid pectin is commonly stirred in near the end; follow a recipe written for the form you have.

Strawberries, cherries, peaches and ripe pears are relatively low in pectin, so their jams may need added pectin or a longer, carefully controlled cook. Apples, citrus peel and underripe fruit contain more; combining them with low-pectin fruit can help the jam set.

Keep dry pectin tightly sealed in a cool, dry cupboard and use a clean, dry spoon, since moisture can make the powder clump and lose effectiveness. Store liquid pectin as its packaging directs, and refrigerate it after opening if instructed.

No. Pectin comes from plants and is suitable for vegetarian and vegan cooking; gelatine is made from animal collagen. They also behave differently in recipes, so swapping one for the other can change both the texture and whether a dish sets.