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How to Sterilize Jars For Canning

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When preserving food using a water bath canning method, it’s crucial to sterilize canning jars before using them in any recipe that calls for processing in less than 10 minutes.

If your recipe calls for processing longer, then sterilizing canning jars may not be necessary.  

Also, know that pressure canning is not necessary when canning any food. The jars, as well as the food inside them, will be sterilized by the temperature. 

Jars used for jams and jellies, tomatoes, juices, fruits, or fermented or pickling recipes that will be processed longer than 10 minutes need not be pre-sterilized either.

Learning how to sterilize jars is an important part of home canning and preserving.

You should also know that you can add additional processing time to your recipe to exceed 10 minutes, and pre-sterilizing will not be necessary.  This will not affect the food flavor either. 

How to Clean Jars for Home Canning

Before every use, wash empty jars in hot water with detergent, rinse well by hand, or wash in a dishwasher. Detergents left on jars may cause unnatural flavors and colors. These washing methods do not sterilize jars. Scale or hard-water films on jars are easily removed by soaking jars for several hours in a solution containing 1 cup vinegar (5 percent acidity) per gallon of water. Source: The National Center for Food Preservation.

In essence, this has already eliminated one popular question people often ask: “Can canning jars be sterilized in the dishwasher?” So, no, the dishwasher is only for cleaning jars.

I don’t have a dishwasher, so I always wash by hand. This makes inspecting each jar for cracks, nicks, and chips much easier. 

different size canning jars on a table waiting to be sterilized

If a jar has any of these, don’t use it! It can be repurposed for a craft or for storing dried herbs.

TIP: It’s also important to mention that sterilizing jars in the oven, microwave, or even an instant pot does not sterilize them either. Boiling water is the only approved safe method.

Sometimes, used jars have a film or hard water spots that look cloudy. You can remove this by soaking them in a homemade cleaning solution made of one cup of 5% vinegar to one gallon of water. Then, soak for several hours. 

If I need to soak jars, I do it the night before in my kitchen sink. Then, when I wash them the next day, they come out nice, shiny, and clean.  

Why Sterilize Jars For Canning

No matter how clean your workspace or home is, surfaces still have bacteria, fungi, and yeast. This is normal; it doesn’t mean your home is not clean.

Bacteria and fungi can grow on glass jars and are too small to be seen by the naked eye. Sterilizing is the only way to kill them. A sterile canning jar is essential for the shelf life of home-canned foods.

Equipment Used

Sterilizing jars is not hard; it just requires some preparation. However, it is well worth it to ensure that your home-canned food is safe for long-term shelf storage

Altitude Adjustments

Altitude affects the temperature at which water boils, so the higher your altitude, the longer it takes for water to boil.  

To properly sterilize jars, they should boil for a full 10 minutes, plus the amount of time added to your level above sea level. See the chart below: 

Feet Above Sea LevelTime for Rolling Boil
0 – 1,00010 minutes
1,000 – 2,00011 minutes
2,000 – 3,00012 minutes
3,000 – 4,00013 minutes
4,000 – 5,00014 minutes
5,000 – 6,00015 minutes
6,000 – 7,00016 minutes
7,000 – 8,00017 minutes

To find out what your sea level is, CLICK HERE and enter your city and state. Your elevation will appear in the large box.

Mine in Tennessee is 860ft, so I don’t add any additional time to recipes when canning.

RELATED: Use “The Complete Beginners Guide To Home Canning” and get comfortable with home canning.

Step-by-Step Guide

Sterilizing canning jars is an important step that takes about 25 minutes. Follow these steps to ensure your jars are properly sterilized:

Water bath canner filled with jars for canning
  1. Wash Jars: Clean canning jars with hot, soapy water.
  2. Place in Pot: Put jars right-side-up in a water bath canner or deep stockpot on a canning rack.
  3. Add Water: Fill the pot and jars with hot water (not boiling) until the water is 1 inch above the jar rims.
  4. Boil Water: Bring the water to a rolling boil using high heat.
  5. Start Timing: Once boiling, start your timer and boil jars according to your recipe and altitude adjustment.
  6. Remove Jars: When the time is up, turn off the heat. Use a jar lifter to remove jars and place them on a clean towel or cutting board to drain. Be careful, as they will be hot!
  7. Keep Water Hot: Leave the hot water in the canner.
  8. Fill Jars: Fill the jars with hot food, add clean lids, tighten screw bands, and place them back into the hot water for processing.

TIP: If it will be longer than 1 hour before you fill the sterilized jars, re-sterilize them. Planning and timing are key to successful home canning.

Check your recipe. If it calls for processing less than 10 minutes + your altitude adjustment, then do the following…

A great source for valuable and accurate canning information is the National Center for Home Food Preparation. Check it out.

Even though sterilizing jars if the recipe calls for processing for more than 10 minutes isn’t recommended, I still do it. It doesn’t hurt a thing.

Not only are my jars sterilized and safe, but the water in the canner is “hot,” so it returns to a boil quickly for processing my recipe. This saves a few minutes waiting for the rolling boil to begin otherwise.

RELATED: Learn the basics of water bath canning with this beginner-friendly guide to preserving food safely and confidently

Use Approved Jars For Canning

If you are making refrigerator jams, you can use pretty much any type of container you prefer: plastic jars, recycled jam jars, glass jars, and even old jars and craft jars.

But if you plan on water bath canning for shelf life to enjoy months down the road, you will need to use only approved glass jars that have been fabricated for home canning.

These jars have gone through a heat process, are tempered to not shatter, and are designed to seal and be stored at room temperature for a long shelf life. They are often called mason jars, but there are other brands on the market. 

Ball canning jars are great for canning, and they can be found not only online but also readily available in grocery stores and hardware stores. 

Cleaning Lids and Rings

Canning lids must also be clean and free of contaminants before they are placed on your filled jars. But they should not be boiled. 

  •  1) In a small saucepan, bring water to a simmer temperature of 180°F (82°C)
  • 2) Place clean lids in water and simmer for 10 minutes or until you are ready to use them
  • 3) Use a magnetic lifter to carefully lift the lids out and place them onto your hot, filled jars.

And then, continue to follow your recipe.

As you can see, sterilizing canning jars is not difficult; it just takes a few extra steps. Of course, canning safety should be first and foremost on our minds when we do it.

Do you feel more comfortable sterilizing your canning jars now? Did you learn something that you didn’t already know? I’d love to hear from you.

FAQ’s

Q: Is a dishwasher hot enough to sterilize canning jars?

A: The NCHFP states that boiling water is the only approved way to sterilize canning jars. Again, this also eliminates microwaves, ovens, and instant pots.

Q: How long do I boil lids for canning?

A: The simple answer is, “Don’t boil lids.” They should be simmered in hot water (180°F) for about 10 minutes or until you are ready to put them on your hot, filled jars.

Q: Can you reuse lids after boiling them?

A: Unfortunately, the answer is no. Lids are designed for one-time use only. Using them more than one time will not seal properly on jars.

More Canning Articles:

How To Sterilize Jars for Canning

canning jars ready to sterilize

Sterilizing canning jars is not always necessary, but, when it is - here's how to do it properly and safe.

Prep Time 5 minutes
Active Time 20 minutes
Total Time 25 minutes
Difficulty Easy
Estimated Cost $1.00

Materials

  • mason jars for canning
  • Boiling Water Canner
  • water

Tools

  • Canning Rack
  • Jar Lifter
  • Clean Towel

Instructions

    Wash jars with hot soapy water and rinse well

    Place jars in water bath canner with rack, and fill both jars and canner with water (not boiling) until jars a completely covered by 1 inch.

    Place on stove with HIGH heat.

    Once water comes to a “rapid boil” start timer and boil for 10 minutes (+ altitude adjustments when necessary). Turn off heat.

    Keep jars in hot water until ready to fill with jam and jellies. Carefully remove jars, one at a time, using a jar lifter empty the water into the water-bath canner. Warning – JARS WILL BE HOT!

    No need to dry them off. Just place hot jar on clean towel, and fill delicious hot food you've prepared for canning.

    Continue to follow your recipe.

pint and half pint canning jars on surface with text overlay - How To Sterilize Canning Jars
various size canning jars on a table surface

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4 thoughts on “How to Sterilize Jars For Canning”

  1. Diane… How would you sterilize your jars, lids and caps if you wanted to use them for storing dry products such as potato flakes, flour, etc. I will also be using oxygen absorbers.

    1. Hi Jim,

      To be honest, I not sure there is a reason for sterilizing for this use. Sterilization is only needed when you are canning a recipe that takes less than 10 minutes to process. I use Mason jars as canisters on my counter with oxygen absorbers for these pantry items and don’t sterilize them. But, if you want to sterilize them, you would follow the same steps and then make sure they are well dried before you put anything into them. To get them dry, you might, after they come out of the water, put them on the dry cycle in your dishwasher if you have one. But again, for storing these items, sterilizing is not required.

      Does this help?
      Dianne

  2. I sterilized my jars and when I took them out of the water they had a film on and in them. I am using them for homemade vanilla extract. Any suggestion on what to do?

    1. Hi C –

      Yes, it sounds like you may have well water or hard water? To keep this from happening, pour 1/4 of 5% white distilled vinegar in the pot of water and boil your jars. The vinegar prevents the white film.

      Let me know how the vanilla extract turns out. I’ve not tried it yet.

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