7 Dangerous Canning Mistakes You Are Making

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Each day, I see articles floating around encouraging dangerous canning mistakes that could cause someone to get sick. If you happen to make one of these mistakes, you might regret it.

Canning is fun and exciting. There is something so refreshing and rewarding about seeing shelves of brightly colored jars. It feels even better when the jars are full with produce you grew throughout the year. A lot of hard work goes into those canning jars.

The last thing you want to do is make a dangerous canning mistake that could lead to you or a loved one getting sick. So, I want to go through some of these canning recommendations that I see frequently.

Before I get started, I know someone will think or say “well, my grandparents did it and they lived.” That is probably true. Chances are your grandparents and great-grandparents did some of these dangerous canning mistakes.

But, we know better now.

Scientists, through extensive studies, have created safety recommendations that ensure what you are canning doesn’t contain dangerous bacteria. The National Center for Home Food Preservation is one of those research institutes that are taking the time to make the safety recommendations.

Cases of poisoning and death from bad canning is rare; that is true. But, it happens! In 2015, an Ohio church potluck experienced a botulism outbreak that caused one death and 20 illnesses. The outbreak was due to badly canned produce. It happens, and you don’t want it to be you or your family that falls victim.

So, let’s take a look at the mistakes you want to avoid.

Mistake # 1 – Flipping Jars Upside Down to Seal

Unfortunately, I still see people recommending this route for sealing jars. It is true that your lid will probably seal, but that doesn’t guarantee it is a solid and secure seal. The jars might seal at first, but later come unsealed. Then, the food will spoil without you realizing.

The biggest reason you don’t want to make this mistake is that the liquids aren’t at high enough temperatures to kill off dangerous spores in the food. One of the reasons that you immerse the jars into a canner is to kill off bacteria. You want the temperature to be so high that no mold can continue to grow.

Mistake # 2 – Reusing Lids that Are Meant for One Use

I know; no one wants to buy lids for each jar. However, the lids you buy from Ball or Wal-Mart aren’t meant to be reused. There is an exception to this rule – Tattler Lids. These lids are more expensive, but they are meant for multiple uses and worth the investment. If you use the wrong lids multiple times, your seal won’t be secure, and your food could spoil. Seriously, no one wants that to happen.

Mistake # 3 – Canning Untested Recipes

Developing your own canning recipes is hard and risky. Using old recipes is also dangerous. You want to make sure you have the right level of acid, the right headspace, processing time and more. I highly recommend that you use reputable recipes. When I first started canning, I purchased the Ball Canning Book. Their new book called – The All New Book of Canning and Preserving – has 300 recipes. It is a wonderful resource with safe canning recipes.

Mistake #4 – Using Paraffin Wax to Seal the Jars

Please, if the recipe tells you to use wax to seal the jars, walk (or close it) away immediately. I understand the idea behind it. The wax is supposed to create a secure seal to keep air out and stopping the growth of bacteria, supposedly. I know that my grandmother talked about doing this when she was younger.

Just like flipping the jars, using paraffin wax doesn’t destroy the bacteria and spores already inside of the food. You can’t guarantee the food is safe, so stick to the lids and rims!

Mistake #5 – Canning Milk, Butter and Flour Products

You might see cream of mushroom canned in the stores and assume you can safely can it at home. The answer is a huge NO. Why? It is because companies create their canned goods at a much higher temperature than we could ever generate in our homes.

One of the most common mistakes I see is an article floating around recommending canning butter by ladling melted butter into jars and flipping them over. There is a whole lot of wrong going on there.

Butter is a low acid food, which means it has to be pressure canned! Botulism loves lower acid, so it can thrive in that environment. The same goes for milk. You cannot safely can milk by heating it and putting it into jars. As it stands right now, there are no safe ways to safely can milk and butter.

The same goes for flour products. You might want to can chicken noodle soup, but it isn’t possible to do at home what they do in large factories. Instead, opt to can chicken soup and add the noodles later.

Mistake #6 – Not Checking for Air Bubbles

It might seem like a silly step. Do air bubbles really cause a problem? The answer is yes, they do. You can run the tool included with your canning set in your jar or use a sterilized butter knife. Air bubbles can give space for spores and bacteria to thrive and live. The step takes 30 seconds, just do it!

Mistake # 7 – Using a Water Bath Canner for Low Acid Food

The last mistake might be the biggest and most dangerous. It is a pet peeve of mine. There are dozens of foods that you cannot safely can in a water bath canner. The difference comes from the acid in the food. The higher amount of acid, the less likely botulism can survive. Foods that have a pH level of 4.6 or HIGHER need to be canned in a pressure canner.

This means your produce in the garden, such as green beans, carrots and corn, must be canned in a pressure canner. If you are canning soups or meat, a pressure canner is necessary. If you opt to use a water bath canner instead, the temperatures will not be high enough to kill off the botulism spores. Even if you boil the jars for hours, it still isn’t enough.

Jellies, jams and pickles are meant for water bath canning, not your produce, meats or soups.


I hope you aren’t making one of these 7 dangerous canning mistakes. If you are, remember that once we know better, we do better. Now that you know the method is unsafe, you can change and ensure your family eats only safely preserved foods.

10 thoughts on “7 Dangerous Canning Mistakes You Are Making

  1. Bethany, These are such good reminders! We also do lots of canning and we constantly have to remind ourselves to return to the recipes that are USDA-approved. I really like your phrase, “once we know better, we do better.” Yes, indeed!

  2. Thank you. I’m. Proud to say I got an A+ on your 7 dangerous canning habits. I think you forgot one. Canning in sn oven. That really scares me.

  3. My pet peeve is leaving the rings on. Jars should be washed after sealing hot in soapy water, rings removed to get any sticky food off so it doesn’t attract bugs.

    1. We remove the rings as well when we plan to store them as well. We didn’t remove our green bean rings, because they’ll probably be gone soon! But, we just canned 7 jars of chicken broth for the pantry. We always store with the rings off. It is dangerous; they have unseal and reseal with the rings on, introducing bacteria.

  4. What about spaghetti sauce and tomato soup? Their are onions, celery, peppers in either one or both recipe. Hot water bath or pressure cooker? I have always put jar, lid in boiling water to sterilize 1 at a time, in a pan, then filled, put lid ring on, set aside. Water always boiling and sauce or soup in 18 qt roaster. When done covered and checked in morning if sealed. I’ve done this my whole life & never gotten sick. My daughter does this also & no one has gotten sick. Must be killing bacteria or in over 50 yrs surly someone would’ve gotten sick.

    I have used wax in my jelly, jam for years. Like 50+ years. Amazing that we’ve never gotten sick. I never even sterilized the jars. Washed in dish washer & filled . Will deffinately water bath.

    Wondering how I’m still alive.

    1. With tomatoes, the acidity levels vary greatly. If you add some under-ripe tomatoes, the acidity levels probably are fine. I always add a bit of lemon juice to my jars. However, canning in a roaster is not recommended nor is canning with wax. I know my grandma did a bunch of things that aren’t recommended and never got sick. You can contact your local extension office if you have questions about safety 🙂

  5. I’ve just recently begun canning. I’d been trying to find a recipe to as closely duplicate Bush’s Black Bean Fiesta as I could. Found one that was just ok, but had way more water than I wanted and used dry, uncooked beans. I wanted them to come out like they do in the can.
    My husband suggested just making the beans as I would any other time ( mostly dry beans
    with some onion, poblano peppers and canned fire roasted tomatoes) and pressure cook it. That’s what I did, however,I did forget to check for air bubbles. There may have been a few tiny ones. The lids all sealed but should I be concerned?

  6. Thanks for publishing this–I get scared when reading some canning recipes online with some or many of these mistakes in them. I’ve been canning for 45 years. You HAVE to play by the rules when canning so you don’t play with people’s lives, even if you’re normally a casual type.

    There are two other issues right in your photo, but not mentioned. One is in the comments already–remove rings and wash jars. If the jar wants to come unsealed due to some issue, you want it to be able to, so no rings.

    Also–don’t double stack canned jars on top of each other. Same reason as above–if it wants to unseal, you want to know it! If you have tall spacing on your shelves–you can buy plastic coated wire shelves on legs at the dollar store to add into your shelves so each jar has it’s own space.

    Lastly, don’t sub out ingredients, add extra, etc., especially when water bath canning. Ball and other legitimate recipes have been formulated to have the right amounts and timing for safety. I bought a digital PH tester online that is used for checking aquariums and pools, for about $12. I check all my water bath canned recipes, even plain tomatoes, to be sure they are acidic enough before putting the lids on. Also, best to work on 1-2 jars at a time, not the entire 7 jars before putting the lids on and putting in canner, unless you’re cold packing.

    Don’t be afraid of water bath and pressure canning! Just do your research and do it right! I’ve saved my family thousands of dollars in food costs over the years. I still can, though not as much as when the kids were at home–I did a couple hundred jars of various foods this year–dill pickles and dilly beans, pickled beets, chili sauce, tomatoes, stewed tomatoes (in the pressure canner), several salsas including tomatilla salsa verde, pizza sauce, pasta sauce, spiced apples and more. Can you tell it was a great tomato year in the garden? Now I get to do the fun things rather than hundreds of jars of veggies. With just the two of us, I usually freeze the veggies.

    Thanks again for these canning no-no’s and sorry for length!

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