Three jars of homemade blackberry and apple jam

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.

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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.

Three jars of mincemeat

Why should we sterilise jars?

It’s very important to sterilise your jars properly so that you remove bacteria in the jars, which could cause your preserves to spoil. Timing is important, because you should put your preserves into a hot jar while the preserves themselves are still piping hot – it’s a good idea so start preparing your jars when the preserves are about 20 mins away from being ready.

How many jars should I sterilise?

It’s a good idea 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 mins 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 then bring to a simmer, then simmer for 20 mins. 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

Clean jars on towel

Heat 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. If using Kilner jars, boil the rubber seals, as dry heat damages them.

Step 2: Fill the jars with preserves

Mincemeat in jars

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

Jars of mincemeat being sealed

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.

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:

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What’s your favourite jam or preserve? Leave a comment below…