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Making homemade jam is a lovely pastime and the results are even lovelier – when it’s done right that is! When getting ready to make jam, one of the first things you need to know is how to sterilise jars – sterilising jars properly will help keep bacteria out of your yummy jam so that it stays fresh for up to a year (or sometimes even longer!). Pick your favourite of these three approaches to sterilising jars for jam making and you can swiftly move onto the fun part!
Sterilising jars in microwave ovens
Sterilising jam jars in microwave ovens is really straightforward and doesn’t take much time at all. Simply carry out the following steps and your jars will be sterilised in a flash:
- Remove any labels from the jar. Try soaking them in hot soapy water first if they’re tricky to remove.
- Use soapy water to make sure that the jar is clean before sterilising.
- Place in the microwave and turn on ‘high’ (usually around 1,000 watts) for 30-45 seconds.
- Place them upside-down on a piece of absorbent kitchen paper (like Plenty) to dry off.
While sterilising jars in microwave ovens works really well, you can’t sterilise metallic lids in this way. Instead of using the old lids you can cover the top of the jars with wax, or buy new lids to seal your jam.
How to sterilise jars in the oven
Sterilising jars in the oven takes quite a bit longer than in a microwave, but it’s long been known as one of the best methods for sterilising jars. You can get the prep done while your jam is simmering and by the time it’s cooked your jars will be ready. Just follow these simple steps:
- Set the oven temperature to 130 C or 270 F – no higher, or you run the risk of the glass breaking.
- Remove the jar labels (soaking if necessary).
- Lay paper in double layers on your oven shelves and arrange the jars on the shelves so that they aren’t touching.
- Shut the oven and set a timer for 20 minutes.
- Use an oven glove to remove the jars and stand them on a heatproof mat to cool.
A quick word of caution here: never add hot jam to a cold jar or cold jam to a hot jar, as this can lead to cracking or, worse still, a jammy explosion.
How to sterilise jars in the dishwasher
Sterilising jars in the dishwasher is probably the easiest method, and works really well if you’ve got an extra hot setting on your machine. Sterilising jars for jam making in this way is straightforward with the following steps:
- Make sure the dishwasher is empty and clean.
- Remove any labels from the jars (soaking them off if necessary).
- Carefully place the empty jars and lids into your machine, ensuring they are secure.
- Run the dishwasher on a cycle that coincides with your jam being ready.
- Remove the jars one by one and lay on fresh, absorbent piece of Plenty kitchen paper to dry.
- Fill the jars with jam and secure with the sterilised lids.
This works well with screw-top and clip-top jars. With clip-top jars it’s best to remove the rubber to make sure that part gets fully sterilised too.
If your jar is tricky to open, add a bit of resistance by placing a strong piece of Plenty kitchen paper over the top of the lid – this should help it twist off more easily.
Now you can take your pick from these three easy ways of sterilising jars for jam making. If you’re making a big batch and have a lot of jars to sterilise, get everyone in the house involved in a jam production line. Whether you go for sterilising jars in microwave ovens, your kitchen oven or the dishwasher, each method will help ensure that your jam is safe to eat and longer-lasting too.