Blackberry jam
Rich, fruity blackberry jam with a deep, sweet-tart flavour - perfect for toast, scones, or desserts, and keeps beautifully for up to a year.
Updated : 13 August, 2025
Easy
About 20 min.
Ingredients
1.2 kilograms
Blackberries
700 grams
Sugar
1
Lemon
Table
Table of volume measurements:
- teaspoon - 5 ml
- dessert spoon - 10 ml
- tablespoon - 20 ml
- glass - 200 ml
Preparation
Step 1
Chill a couple of small plates in the freezer several hours before starting if you don’t have a sugar thermometer.
Step 2
Wash the blackberries and place them in a large, heavy-based saucepan. Cook over medium-high heat for 8-10 minutes, stirring occasionally, until most berries have broken down and the remaining ones are nearly submerged in their juice.
Step 3
Gradually add the sugar in thirds, stirring between each addition, then pour in the lemon juice. Bring to the boil, then reduce to a gentle rolling boil and simmer for 8-10 minutes, until the jam reaches 105°C/220°F on a sugar thermometer. At this point, the bubbles will appear smaller, showing most of the fruit’s water has evaporated.
Step 4
If testing without a thermometer, drop a little jam onto one of the chilled plates. Leave briefly, then push your finger through it. If the surface wrinkles slightly as if forming a skin, it’s ready. If not, cook for a few more minutes and test again with your second plate.
Step 5
Pour the hot jam into six warm, sterilised jars and seal immediately. Store unopened in a cool, dark place for up to 12 months. Once opened, refrigerate and consume within two weeks.