You will love this easy recipe for small-batch Blueberry Jam, made without pectin, from ripe, aromatic berries at the height of their season. This is the best way I know to preserve the flavours of summer to enjoy throughout the cooler months ahead. Aside from tasting fantastic, this jam is so easy to make!
2tablespoon(40 ml) lemon juice - freshly squeezedSee Notes 3 and 4
To Sterilise the Jars:
Choose glass jars with an airtight, metal lid and ensure they have been washed in the dishwasher or by hand in hot soapy water then rinsed well.Preheat the oven to 130 C (265 F). Place upright jars and lids on a baking tray. Heat in the oven for at least 20 minutes, then remove and immediately fill with jam. See Note 5.
To make the Blueberry Jam:
Place two small saucers or plates in the freezer. See Note 6.
Wash and thoroughly dry blueberries.Add the blueberries, sugar and lemon juice to a large saucepan and mix well with a long-handled wooden spoon.
Turn the heat on low and stir until the sugar dissolves. (This can take 5-8 minutes)If sugar crystals get caught on the side of the saucepan, scrape down with a spatula.
Once the sugar is dissolved, increase the heat to a rolling boil.Boil for 10 minutes, stirring frequently. After 10 minutes, begin to check for the setting point. Your jam will likely take between 10-15 minutes, but it will depend on the width of your saucepan and how rapidly the jam is boiling.
Turn off heat and spoon a little of the jam onto one of your chilled saucers.Let it stand for 30 seconds to cool, and then run your finger through it. If it wrinkles, even slightly, it is ready. If it is still quite liquid, put it back on the heat and boil for a further 1-2 minutes, and retest until ready. Alternatively, you could use a candy thermometer. Setting point is reached when the thermometer reaches 105 Degrees C (220 F).
Skim any scum off the top of the jam with a spoon.
Allow the jam to sit for 5 minutes to allow the fruit to disperse evenly.
Carefully ladle your jam into your hot jars and put the lids on immediately. Allow the jam to cool completely. Wipe the jars to remove any spills, and store the jam in a cool, dark place.
Ensure your fruit is freshly picked and of good quality. Avoid fruit that is bruised or over-ripe. The blueberries contain pectin which aids in the jam setting. If your fruit is older, it will contain less pectin.
Do not reduce the amount of sugar. Whilst the sugar sweetens the fruit it also acts as a preservative and helps the jam to set. If you reduce the sugar, your jam may not be shelf-stable and may become mouldy.
The Australian tablespoon is 20ml or 4 teaspoons. In many other countries, the tablespoon is 15ml or 3 teaspoons. Please adjust the measurement if necessary.
Lemon juice not only balances the sweetness of the sugar, but it also contains acid and pectin which help to set the jam.
Properly sterilising your jars is an essential process to remove bacteria that could cause your preserves to spoil. Wash the jars and lids either in the dishwasher or by hand in hot soapy water, and rinse well. Do not dry them with a tea towel. Place jars and lids on a baking tray. If you are using Kilner jars with rubber seals, be sure to remove the seals before placing the jars in the oven. The dry heat of the oven would damage the seals. Boil the seals separately in a saucepan for about 10 minutes. Heat the jars in the oven for at least 20 minutes. When your preserves are ready to bottle, use thick oven mitts or jar tongs to remove the jars. Do not place them on a cold surface as they may shatter. I place mine on a wooden chopping board which I cover with a tea towel. Always sterilise a few more jars than you think you will need. It is better to have too many jars than not enough.
The chilled plates are used to quickly cool the jam when testing the setting point.
Always choose a large,wide saucepan that has enough height to enable the jam to boil vigorously. More surface area means the liquid will evaporate faster; having sufficient height means you can boil the jam at a higher heat and maintain the fresh flavour of the blueberries. Avoid aluminium, copper or iron pans; the acid in the fruit may react with the pan, giving the jam a metallic taste.
Do not use a metal spoon, it will become very hot. A long-handled wooden spoon is important to avoid being burnt by a splash from boiling jam.
My jam reached its setting point about 10 minutes after it began to boil rapidly. Boiling time will vary depending on the size of your saucepan and the heat that you apply.
If you prefer smooth jam, use an immersion blender carefully once you have taken the blueberry jam off the heat.
If your finished jam has not set as much as you would like, don’t worry, it will still be delicious stirred into some plain yoghurt or served over our No-churn Vanilla Ice Cream. Or, if it is slightly over-set and is very firm, it will be a lovely accompaniment on a cheese board.
Please note, the nutritional information is based on one whole jar. The nutritional information is an estimate only.