How to sterilise jars for jams and preserves
If you're making your own marmalade, jam, chutney or pickle, make sure your jars are clean to maintain freshness. We show you how in three easy steps.
If you’re making your own preserves, make sure your glass jars are scrupulously clean so that the contents won’t perish.
Read these top tips for sterilising jars, then follow our step-by-step instructions below for the process. Our example shows the jars being used to keep homemade mincemeat, but you will find this technique useful when making any marmalade, jam or chutney.
Want to get started on a batch of fruity jam? Check out our top tips on how to make strawberry jam and watch our video to learn about the all-important setting point and how to test jam. Experiment with more fresh flavours from our ultimate jam collection and kit out your kitchen with our review of the best jam making equipment.
Basic process for sterilising jars
- Heat the oven to 140C/120C fan/gas 1.
- Wash the jars in hot, soapy water, then rinse well.
- Place the jars on a baking sheet and put them in the oven to dry completely – this should take around 10 minutes but can vary.
- If using jars with rubber seals, boil the seals, as dry heat damages them.
Read our guide below for more details, along with how to use the jars for jams and preserves.
Why should we sterilise jars?
It’s very important to sterilise jars properly to remove bacteria, which could cause your preserves to spoil. Timing is important, because you should put your preserves in a hot jar while the preserves themselves are still piping hot – start preparing your jars when the preserves are about 20 minutes away from being ready.
How many jars should I sterilise?
It's best to sterilise one or two more jars than you think you’re going to need to make sure you have enough for all of the preserve mixture.
How to prepare jars with a rubber ring seal
For jars with a rubber ring seal, remove the seal before washing the jars and place in a small saucepan. Cover with water and boil for 2-3 minutes to sterilise.
How can I extend the shelf life of homemade preserves?
Fill the jars with the preserves, screw on the lid then wrap each one up in newspaper. Pop the wrapped jars in a large saucepan, cover with water, bring to a simmer, then simmer for 20 minutes. Turn the heat off, then leave the jars to cool completely in the pan.
How to sterilise jars
Step 1: Wash the jars and heat them in the oven
Heat the oven to 140C/120C fan/gas 1. Wash the jars in hot, soapy water, then rinse well. Place the jars on a baking sheet and put them in the oven to dry completely. This should take around 10 minutes but can vary. If using jars with rubber seals, boil the seals, as dry heat damages them.
Step 2: Fill the jars with preserves
Spoon your homemade preserves into the hot jars and pack down well to remove any air bubbles. If you’ve made jam or chutney, it’s important that the mixture is still hot when filling the jars.
Step 3: Seal and label the jars
Place a waxed disc directly over the surface to create a seal, then add a lid or secure on a cellophane lid with an elastic band. Label and add pretty fabric tops and ribbons if you’re giving as gifts.
More like this
Watch our video on how to sterilise jars for a visual demonstration.
Making homemade preserves for your storecupboard or as gifts? Our guides and videos are packed with expert advice:
- Top ten tips for making marmalade
- Top tips for making jam
- How to test jam video
- DIY chutney: To make or to buy?
- How to make chutney video
What's your favourite jam or preserve? Leave a comment below...
