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Mary Berry Plum Jam Recipe
Nancy Wilson

Mary Berry Plum Jam

5 from 4 votes
Mary Berry's classic plum jam, made with equal weights of fruit and sugar. No pectin needed, just plums, sugar, water, and a knob of butter for a clear, glossy set.
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Prep Time 15 minutes
Cook Time 30 minutes
Additional Settling Time 15 minutes
Total Time 1 hour
Servings: 5 jars
Course: Preserves
Cuisine: British
Calories: 50
Ingredients Equipment Method Notes

Ingredients
  

  • 1 kg plums washed, halved, and stoned; slightly under-ripe if possible (see note)
  • 150 ml water
  • 1 kg granulated sugar
  • 1 small knob butter about 10 to 15g

Equipment

  • Large, heavy-based preserving pan or stockpot
  • Wooden spoon
  • Small plate (chilled in the freezer, for the set test)
  • Ladle
  • 5 sterilised 340g jars with lids

Method
 

  1. Soften the fruit: Put the halved, stoned plums in a large pan with the water. Simmer for 10 to 15 minutes until the skins are completely soft.
  2. Dissolve the sugar: Add the sugar and stir over low heat until completely dissolved, with no grains left.
  3. Boil rapidly: Turn up the heat and boil for about 10 minutes at a full rolling boil, stirring occasionally.
  4. Test for set: Remove from heat. Spoon a little onto a chilled plate, wait 30 seconds, then push with your finger. If it wrinkles, it's set. If not, boil for 2 more minutes and retest.
  5. Finish with the butter: Stir in the knob of butter to clear the surface foam.
  6. Settle and pot: Let the jam stand for 15 minutes, then ladle into warm, sterilised jars and seal.

Notes

  • Makes about 1.6 to 1.7kg of jam, roughly 5 standard 340g jars.
  • Use slightly under-ripe, firm plums for the best natural pectin and a more reliable set.
  • Sealed and unopened, keeps up to 1 year in a cool, dark place. Once opened, refrigerate and use within 4 to 6 weeks.
  • Do not reduce the sugar. It's essential for the set and shelf life, not just sweetness.
If you're picking plums yourself or choosing them at a shop, go for ones that are firm with a little give, not soft and squishy. You'll still get a jam that tastes great, and you're far less likely to end up boiling it for an extra 20 minutes trying to force a set that isn't coming.