If you’ve ever seen a recipe for jam or chutney and reacted with a big ‘HUH?’ to ‘store in sterilised jars’, then I’m here to help! Sterilising jars is SUPER straightforward and is essential when you’re making anything you want to store at room temperature for a long time.
Why do jars need to be sterilised?
Whenever you’re making something like jam, chutney or any kind of preserve, the idea is you want to keep it for a long period of time. To do that, they need to be stored in something that’s properly sterilised.
That just means that any lingering bacteria have been removed from the jar so it protects whatever you’re putting into it and allows it to keep at room temperature.
If you put your preserves into a jar that’s just been washed by hand, you’ll find it will spoil quickly. That’s because the jar needs to be heated to a point where no harmful bacteria can survive.
Luckily, sterilising jars is quick and easy and I’ll show you how below!
How to sterilise your jars
Start by heating your oven to 160C fan and line an oven tray with baking paper. The idea is you want to add your finished jam or preserve to the sterilised jars when they’re BOTH still warm. I find if I start to sterilise the jars about 30 minutes before the preserve is ready, that works out well timing wise.
Wash the jars – and lids – you want to sterilise in hot, soapy water. Then give them a rinse but DON’T dry them. Pop them upside down on the lined oven tray.
Put them in the hot oven for at least 20 minutes, then remove them one at a time when you need them. Let them cool slightly before filling with your preserve (make sure the temperature of the preserve and the jars is similar). Let them sit for about 15 minutes before sealing with the lids. And you’re done!
PRO TIP: If your jars have rubber seals, make sure you remove them before you put them in the oven.
An important thing to remember
Glass reacts to extreme temperature changes. That means you should never add cold food to hot jars or hot food to cold jars. The glass will shatter, which not only makes a big, annoying mess but it’s also super dangerous. I have done this before and luckily my jar was in the sink so it was easy enough to clean up, but it meant a whole batch of chilli jam was wasted.
Get started with your sterilised jars
Now you know how to sterilise jars, here are a couple of recipes you can try to use your new skill!