Blackberry Jam

Put the blackberries into a bowl with the sugar and mix gently. Cover the bowl with plastic wrap or a plate and leave to sit overnight in the fridge.

The next day, lightly squash the berries with your hands or a potato masher, then transfer to a medium saucepan. Place over low heat, add the lemon juice and zest, and stir until the sugar has dissolved.

Put some small plates in the freezer to check for setting point later.

Turn the heat up to medium and boil the jam rapidly until setting point is reached, stirring occasionally to avoid burning on the base. This jam is quick to cook, approximately 20-30 minutes, and it tends to set quite firmly, so be careful not to overcook it.

Once the jam has been bubbling away for 15 minutes, take one of the plates out of the freezer and drop a generous spoonful onto it. Let it sit for a minute or so, then run your finger through it. If your finger leaves a clear line that stays put, your jam has reached setting point. If the jam comes back together quickly, it needs a little longer. Place the plate back in the freezer and retest in a couple of minutes.

Meanwhile, sterilise your jars. You'll need about 2 x 400ml glass jars with metal lids. To sterilise jars, give them a wash in hot soapy water and a good rinse, then place them upright in a baking dish in a cold oven. Heat the oven to 110°C and, once it has reached temperature, leave the jars in the oven for about 10–15 mins, or until completely dry. Remove the tray carefully from the oven, then leave to cool slightly. The lids can have a hot soapy wash and then be left to air dry or be dried with a clean paper towel.

Carefully pour the hot jam into the hot jars and seal immediately. Store the jam in a cool, dark place for up to 12 months. Once opened, refrigerate and use within a month.

If you want to extend the shelf life of your jam, you can heat process the jars. Get the biggest pan you have, such as a stockpot, and put it on the stovetop. Lay a folded tea towel in the bottom of the pan, then sit your filled, lidded jars on the tea towel. Make sure your lids aren’t on too tight! Pour in enough warm water to cover the jars, either completely or at least until three-quarters submerged. Bring to the boil over medium heat and simmer for 15 minutes.

Carefully remove the hot jars from the water using preserving clamps or a very thick cloth. Line your jars up on the benchtop and let them sit overnight. As they cool, a vacuum will form inside each jar and suck down the lid, sealing them securely. These jars can be safely stored in the pantry for up to 2 years. If you have concerns about the seal of any of your jars, store them in the fridge and use their contents within a month.