Food I cook for my family, baking recipes, cookbook reviews, and your cooking questions answered
It’s incredibly rewarding (and easy) to make your own berry jam. The reason homemade jam tastes so good is that it’s freshly made in small quantities. Fresh jam has a superior taste, and often people don’t realise how much freshness contributes to the flavour.
Use fresh berries, if they are cheap and in season. Slightly under-ripe fruit is best. Through the rest of the year, I often use bags of frozen berries that are easily available. I usually mix the berries, as I like to use some tart berries like blackberries. But you can make the same recipe with just one variety of berries as well.
Either way steep the fruit in the sugar overnight. This shortens the cooking time and keeps the jam more flavourful and fruity. Adding lemon juice helps to increase the tartness of the jam, so feel free to skip or add more to taste.
The magic temperature in jam making is 104C. An instant-read thermometer would make it easy to check. If you don’t have one, see note below to test for “set”.
Read the notes before you start off. The jam jars are easy to sterilise in the oven and you can do it simultaneously as you cook the jam. You do need a funnel to pour the hot jam into the prepared bottles.
Ideally, mix the fruit and the sugar in a bowl and leave overnight on the kitchen counter (if using frozen fruit) or in the fridge if using fresh. I don’t cut the berries except perhaps large strawberries.
Next day, transfer the mixture to a large saucepan. (Use the largest pan you have as the quicker the jam cooks, the better it will taste).
Place on gentle heat and stir until the sugar fully dissolves and you can't see any grains. Add the lemon juice and increase the heat at this point and boil rapidly until the temperature reaches 104C (see note above). It should take about 5-10 minutes. At this stage, you can taste a bit of the jam and add more lemon juice if needed.
Once it passes the “set” test, remove from heat immediately. Using a funnel pour into the sterilized jam jars. Cover immediately but don’t tighten the screwtop lids completely, remembering that both the jars and lids are hot. Leave to cool completely. Check lids and tighten and store in a dark cool place until use.
The easiest way to sterilise jam jars: wash in soapy water, rinse well and then place both the jars and lids, into a moderately hot oven at 160C-170C for 15 minutes. Take out the jars and use within 10 minutes.
To test for "set" without a thermometer put a drop of the jam onto a very cold saucer (you'll need to put the saucer into the fridge or freezer first to ensure it's really cold). After a few seconds, push the jam with your finger. If the jam surface wrinkles then it has reached setting point and is ready. If it's not ready then continue to boil, testing every few minutes.