How to Sterilise Glass Jars and Bottles for Jams, Chutneys, and Cordials
If you’re planning to make homemade jams, chutneys, or cordials, one of the most important steps—before you even start chopping fruit—is sterilising your jars and bottles. This essential step ensures your delicious creations stay fresh, safe to eat, and free from unwanted bacteria or mould.
In this post, we’ll walk you through simple, reliable methods to sterilise glass containers at home, using tools you probably already have in your kitchen.
Why Sterilisation Matters
When you preserve food, you’re locking in flavours and nutrients—but you also want to make sure you’re not sealing in bacteria. Sterilising jars and bottles kills any lingering microorganisms, reducing the risk of spoilage and foodborne illness.
When Should You Sterilise?
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Just before filling the jars or bottles—so they’re still hot when filled.
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Every time you make preserves, even if the jars look clean.
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Whether using new or recycled containers.
What You’ll Need
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Clean glass jars or bottles with lids
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A large oven or deep saucepan
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Tongs or a jar lifter
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Tea towel or drying rack
3 Easy Methods to Sterilise Jars and Bottles
1. Oven Method (Great for Jars and Bottles)
Steps:
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Preheat your oven to 120°C fan/140°C (285°F).
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Wash jars and lids thoroughly in hot, soapy water. Rinse well.
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Place jars (not rubber seals or plastic lids) upside down on an oven tray.
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Heat in the oven for at least 20 minutes.
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Turn off the oven and leave the jars inside until you’re ready to fill them.
Tip: Only use this method for heat-safe glass. Don’t put cold jars straight into a hot oven—they might crack.
2. Boiling Water Method (Best for Lids and Small Jars)
Steps:
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Fill a large saucepan with water and bring to the boil.
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Submerge jars and lids completely. Boil for 10 minutes.
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Carefully remove with tongs and place on a clean tea towel to air dry.
Caution: Don’t dry them with a cloth—it might reintroduce bacteria.
3. Dishwasher Method (For Quick Batches)
Steps:
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Run jars and bottles through a hot dishwasher cycle without detergent.
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Use the highest temperature setting.
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Leave them in the dishwasher until you’re ready to use.
Note: This method is best for immediate use—don’t leave jars standing too long afterwards.
A Word About Lids and Seals
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Metal lids with rubber seals can be sterilised by boiling.
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Plastic lids should be washed in hot soapy water and rinsed in boiling water—but avoid high oven temperatures.
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Rubber rings (like those used with Kilner jars) should be boiled, not baked.
Ready to Fill?
Always fill hot jars with hot jam or cordial—never pour hot mixtures into cold jars, as this can cause thermal shock and breakage. Use a funnel for clean filling, wipe the rim with a sterile cloth, and seal immediately.
Final Thoughts
Sterilising jars might seem like a small step, but it’s one of the most important parts of successful home preserving. Taking the time to do it properly means your jams, chutneys, and cordials will stay delicious for months to come.
Happy preserving!
