How To Sterilize Jars for Jams, Pickles and Preserves

Using clean, sterilized jars for storing homemade jams, festive mincemeat, chutneys or pickles is essential if you wish for your lovely produce to last and not spoil. 

Sterilizing and good hygiene methods for these jars is a key step in the preserving process.

If you do not annihilate or kill all of the potential bacteria, yeasts, fungi, organisms and often unseen bugs that lurk inside these jars, then your food will never remain fresh within the sealed vacuum of the jar.

Clean jars are essential for home food preservation.

There are a few methods you can choose from for sterilizing your jars. You don't need a water bath canner, or pressure canner for these techniques. Here are my tips and tricks for jar sterilization. 

Table of Contents

Inspect Your Jars

The very first step, before even a drop of boiling water is used, is to inspect your jars. Pick them up and look them over thoroughly searching for any cracks, breaks or chips.

Any damage, even the smallest of chips or cracks, means the jar must be discarded. It will never survive the heat of the sterilization process. 

Hot, Soapy Water Wash

The very next pre-sterilization step is to thoroughly wash your jars in hot soapy water.

Give them a good soaking and scrubbing both inside and out. Then rinse completely in very hot, scalding water.

Next choose one of the following three methods for jar sterilization ....

Pot of Boiling Water Method

Remove the lids and rubber seals from the jars.

Place the washed jars on a rack set in the bottom of a deep pot and cover with hot water.

If you do not have a rack make a small ring with aluminium foil on which to balance the jar. Place the jars right-side up.

Bring the water to a boil then lower the heat and boil the jars for a full 15 minutes with the lid on the pot. 

If you live at altitudes higher than 1000 feet you need to boil the jars for additional time. It is usually recommended to to boil for one additional minute for each extra 1,000 feet of elevation.

At the end of the boiling time turn off the heat and let the jars stand in the hot water.

Place the lids or rubber seals in a separate pot of hot water and bring to a boil. 5 minutes simmering is fine for the seals and lids.

When you are ready to fill the jars place the upside down on a rack or clean kitchen towel to dry. Resist the temptation to dry them out with a towel since this would recontaminate them.

Fill the jars while they are still hot.

Oven Method For Jar Sterilization

Pre-heat the oven to 350 degrees Fahrenheit or 180 degrees Celsius.

Once you have washed your jars and lids in hot soapy water, be sure NOT to dry them.

Instead, while they are still wet, place them standing upside down on a roasting tray.

Place the roasting tray of wet jars into the preheated oven and leave them there for 15 minutes. 

Remove from the oven and allow to cool slightly.

Place any rubber seals in a pot of hot water and simmer for 5 minutes to make sure they too are clean.

Dishwasher Method

Separate the lids and rubber seals from your jars.

Next place the jars and all the pieces onto the top rack of your empty dishwasher.

Run it on the hottest wash cycle available on your machine WITHOUT any detergent or cleaning solution added.

Schedule your dishwasher cycle to finish just as you are ready to fill them. You can leave the jars in the dishwasher to cool slightly and stay warm until you are ready to fill them.

Filling And Covering The Jars

Once your jars are sterilized it's time to fill them while still hot. Use your oven mitts and tongs for safety.

When handling the jars be careful not to touch the rims of the jars. Any contact can reintroduce bugs and critters you have painstakingly killed off during the sterilization process.

Do not over fill the jars. Leave about a ¼ inch or ½ cm gap from the top of the jar and the contents. 

Cover the jars while still hot. You can use the sealed lids that come with today's preserving jars.

The old way was to top the jar with a disc of wax paper or baking parchment and seal it tightly with string.

In today's world, if you do not have a sealed lid, it's easier to top the jar with a wax paper disc, then with another layer of  plastic wrap, and finally seal it with a tight rubber band.

Safety Tips

I know some readers could be tempted to sterilize jars by simply swishing boiling water around inside them. Be fair warned. This is not adequate heating to kill off germs.

And remember be very careful when handling hot jars and lids. Use oven gloves and tongs to keep your finger tips from scalding.

Storage Duration In Sterilized Jars

Once preserves or jams are sealed tightly in properly sterilized jars they should keep perfectly for 6 months. It's best to store them in a cool, dark place.

Some preserves last longer than others so do check each recipe individually. Preserves that contain alcohol, like festive mincemeat, can last for up to a year.

This method can be used for home canning of jellies, jams, marmalade, chutneys and preserves.

This method is used for storing homemade mincemeat, a festive treat in Ireland.

Remember, that even brand-new jars must be sterilized when preserving foods.

If you re-use jars from commercially bought jams and preserves, breakage can easily occur. They are not as robust as specially made serilizing canning jars.

If you use your jars over and over again and you find there is some build-up or scale on the outside from boiling in hard water, you can remove the scale with this technique. Soak the cloudy jars in a gallon of water with one cup of vinegar added. I use clear white vinegar for this purpose.

Happy Preserving To All

I hope you found this little tutorial to be helpful, and have some fun cooking and preserving your favorite jams, pickles and preserves.

Thanks for following my recipes and ramblings.

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