Name: Mary Berry Plum Jam Recipe
Prep time: 20 min
Cook time: 1 h
Total time: 1 h 20 min
Ingredients: 900g ripe plums, stoned and roughly chopped; 750g granulated sugar or jam sugar; 120ml cold water; 1 tablespoon fresh lemon juice; 10g unsalted butter

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This plum jam is a deep ruby preserve with a thick, glossy set and a bold, sweet-sharp flavour that sits somewhere between fruity and lightly tangy. The colour is a rich burgundy that deepens as the jam cools in the jar. It spreads smoothly on warm toast or scones without being overly sweet or cloying.

What makes this version reliable is its straightforward method, which suits first-time jam makers as much as seasoned ones. The balance of sugar and natural pectin from the plum skins means the set is consistent without needing added pectin. From start to finish, this recipe is ready in around 1 hour and 20 minutes.

Ingredients

For the jam

900g ripe plums, stoned and roughly chopped
750g granulated sugar or jam sugar
120ml cold water
1 tablespoon fresh lemon juice

To finish

Knob of unsalted butter (approximately 10g)

How to Make Mary Berry Plum Jam Recipe

Sterilise the jars: Wash three to four 300ml glass jars and their lids thoroughly, then place them upright on a baking tray in an oven set to 140°C (fan 120°C / gas 1). Leave for at least 15 minutes while preparing the jam. Sterilising while the jam cooks means the jars are hot and ready when needed, reducing the risk of spoilage.
Soften the plums: Place the chopped plums and water into a large, heavy-based saucepan or preserving pan. Bring to a gentle simmer over a medium-low heat and cook for 10 to 15 minutes, stirring occasionally, until the plum flesh is completely soft and beginning to break down.
Add the sugar and lemon juice: Tip in all the sugar and the lemon juice, then stir slowly over a low heat until every grain of sugar has dissolved fully before raising the temperature. Rushing this stage and boiling before the sugar dissolves can cause the jam to crystallise during storage.
Bring to a rolling boil: Once the sugar has dissolved completely, increase the heat to high and bring the mixture to a rapid, rolling boil. Allow it to boil hard for 10 minutes without stirring. Place a small plate in the freezer at this point for the set test.
Test for a set: After 10 minutes, remove the pan from the heat. Drop a small amount of jam onto the chilled plate and leave for 30 seconds, then push it gently with a fingertip. If the surface wrinkles and holds its shape, the jam has reached setting point. If not, return the pan to the heat for a further 3 to 5 minutes and test again.
Skim and finish: Once setting point is reached, add the small knob of butter and stir it through. This disperses the foam that forms on the surface, leaving the jam clear and glossy. Use a spoon to remove any remaining surface scum.
Pot the jam: Leave the jam to cool in the pan for 10 minutes so it thickens slightly and the fruit stays suspended rather than floating to the top. Carefully ladle into the hot sterilised jars using a heatproof jug or jam funnel, filling to within 5mm of the top. Seal immediately with the lids.
Cool and label: Leave the jars to cool completely at room temperature before labelling with the date. The jam will continue to firm as it cools over the next few hours.

Tips for the Best Mary Berry Plum Jam

Why has my plum jam not set properly after cooling?

The jam most likely did not reach a full rolling boil, or it was not boiled for long enough. Return the opened jam to a clean pan, bring back to a rolling boil, and test the set again on a cold plate before re-potting.

Why is my plum jam cloudy rather than clear?

Stirring the jam during the high boil introduces air bubbles that cloud the preserve. Allow the jam to boil without stirring, and add the knob of butter at the end to help break up surface foam before jarring.

Why does the fruit float to the top of the jar?

Potting the jam while it is still very hot causes the fruit pieces to rise. Allow the jam to rest off the heat for 8 to 10 minutes before ladling into jars, which gives it enough body to hold the fruit in suspension.

Why does my jam taste more bitter than fruity?

Plum skins and stones contain compounds that become bitter if the fruit is cooked too rapidly at the start. Softening the plums slowly over a low heat before adding the sugar draws out the natural sweetness and mellows any sharpness.

Why does the set vary between batches even when I follow the same method?

The natural pectin level in plums varies depending on ripeness. Slightly underripe plums set more reliably than very soft, overripe fruit because they contain more pectin. If your plums are very ripe, using jam sugar with added pectin will give a more consistent result.

Serving Suggestions

Spread generously on thick slices of white farmhouse toast with salted butter.
Serve alongside a warm scone with clotted cream for a classic afternoon tea pairing.
Spoon over a plain yoghurt or thick Greek-style yoghurt for a simple breakfast.
Use as a filling between sponge layers in a Victoria sandwich for a fruity alternative to strawberry jam.
Pair with a mild soft cheese such as brie or camembert on a cheese board for a sweet, sharp contrast.

Storage

Room Temperature

Sealed and sterilised jars can be stored in a cool, dark cupboard for up to 12 months.

Refrigerator

Once opened, store the jar in the refrigerator and use within 6 to 8 weeks. Bring to room temperature for 10 minutes before serving if you prefer a softer, more spreadable consistency.

Freezing

Plum jam can be frozen in freezer-safe containers with a 1cm gap left at the top to allow for expansion, and will keep well for up to 12 months. Defrost overnight in the refrigerator and stir before use, as the texture may be slightly softer after freezing.

Nutrition

Calories: 48 kcal
Carbohydrates: 12g
Protein: 0.1g
Fat: 0.1g
Saturated Fat: 0g
Sodium: 1mg

Nutrition values are estimates based on a standard serving of one tablespoon and may vary depending on the specific ingredients used and the ripeness of the fruit.

FAQs

Can I use frozen plums instead of fresh ones for this recipe?

Yes, frozen plums work well in this jam. Defrost them fully and drain off any excess liquid before cooking, as frozen fruit releases more water, which can affect the set and extend the boiling time needed.

Can I make this plum jam without added sugar using a sweetener?

Standard granulated or jam sugar is needed for both the set and the preservation. Artificial sweeteners do not behave in the same way during jam making and will not produce a reliable set or preserve the fruit safely for long-term storage.

Can I leave the plum skins in the jam or do they need to be removed?

The skins can stay in the jam and will soften fully during cooking, adding both colour and pectin to help the set. If you prefer a very smooth, skin-free preserve, press the softened cooked plums through a sieve before adding the sugar.

Can I halve this recipe if I only have a small amount of plums?

Yes, the recipe scales down well. Use 450g plums, 375g sugar, 60ml water, and half a tablespoon of lemon juice. The boiling time may be slightly shorter, so check the set after 7 to 8 minutes rather than the full 10.

Can I add any spices to this plum jam to vary the flavour?

A cinnamon stick or two added during the initial softening stage gives a warm, spiced background note without overpowering the fruit. Remove the cinnamon before adding the sugar. Star anise or a strip of orange zest also pair well with plum.

Conclusion

This Mary Berry plum jam recipe produces around 3 to 4 jars of a richly coloured, well-set preserve with a clean, fruity flavour. The method is straightforward enough for a first attempt at jam making, and the result is a reliable, glossy preserve that keeps well and works across a wide range of uses, from morning toast to baking.

The key steps, softening the fruit slowly, dissolving the sugar fully before boiling, and testing the set carefully, make the difference between a jam that sets cleanly and one that stays runny. Follow each stage with a little patience and the results will be consistent every time. If you give this recipe a go, share how it turns out in the comments below. You might also enjoy this Mary Berry vegetable soup recipe for another reliable, comforting classic from the same collection.