10 Canning Mistakes You Don’t Want to Make

Each day, I see articles floating around encouraging dangerous canning mistakes that could cause someone to get sick.

Canning is fun, refreshing, and rewarding; seeing shelves full of home-canned food is satisfying. Those who are new to canning need to make sure they don’t make any serious canning mistakes.

Not all canning mistakes are dangerous, but some are. In fact, some canning mistakes can kill you.


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.

Luckily, most canning mistakes are simple and won’t lead to any horrible consequences. So, let’s take a look at the mistakes you want to avoid.

8 Canning Mistakes You Need to Avoid

Take time to read these mistakes and avoid them. If you end up making a mistake and your jam recipe fails, check out these common problems when making jams and jellies and how to fix them.

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 it.

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.

Related: Can You Reuse Canning Lids?

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 the cream of mushroom canned in the stores and assume you can safely can it at home. The answer is a huge NO.


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 When You Need a Pressure Canner

One of the dangerous canning mistakes you can make is using a water bath canner when you need to use a pressure canner.

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 the amount of acid, the less likely botulism can survive.

Related: Acidity for Canning: Why It Matters for Safe Canning

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.

A few foods that you can preserve in a boiling water bath canner include:

  • Pickles
  • Jams
  • Jellies
  • Salsa
  • Tomatoes (with added acid)

Non-acidic foods need a pressure canner, which isn’t a pressure cooker. No, you can’t use your Instant Pot pressure cooker for canning – SORRY!

A pressure canner is a must; they reach temperatures and pressures that are high enough to kill bacteria.

Examples of foods that you need a pressure canner include:

  • Vegetables
  • Soups
  • Broth
  • Meat
  • Dry Beans

Mistake #8 – Overfilling Jars

When you read a canning recipe and it tells you how much headspace to leave, don’t ignore it! Recipes indicate how much headspace you need; the amounts vary from one inch to 1/4 of an inch.

What is headspace?

Headspace is the space between the top of the food and the top of the rim of the jar. Jars aren’t meant to be filled to the tiptop.

If you overfill canning jars, the lids fail to seal properly, and the liquids might siphon out, spilling over the sides.

This canning mistakes happen to nearly everyone when they first start canning. Make sure you have a headspace measurer and a canning funnel.

Mistake #9 – Not Looking for Cracks or Chips in the Jars

Recently, my husband remembered why this canning mistake sucks so much. He lost a quart of sloppy joes that he canned because he forgot to check for cracks.

Always check over all of your canning jars before using them. The heat from the food or canners causes something as small as a hairline crack to shatter entire jars.

No one wants to have wasted food, so inspect the jars!

Typically, I inspect the jars when I scrub and clean them. Slowly turn the jar over in your hand as you look for cracks and chips. Chips happen most commonly along the rims or the bottom of the jars.

Mistake #10: Not Using Hot Jars

An important step each time that you can is to heat the jars up beforehand. Failing to do so increases the risk of siphoning.

What is siphoning?

Siphoning happens most often with fruit and tomato products, but it’s not uncommon with vegetables and meats. It’s when you lose liquid around the edges of your jars.

The most common reason for siphoning is failing to use proper headspace. The second common reason is not using hot jars.

A loss of liquid happens when a drastic change in temperature happens. So, filling hot liquid into a cold jar that then are placed into a hot canner increases the chances of siphoning.

Preheat your jars to stop the loss of any liquid.

How to Fix Canning Mistakes

In many cases, if you make one of these canning mistakes, it’s possible to fix it if you caught the error soon. That means, after 24 hours, the damage is done, and there is no fixing the mistake.

However, if it’s within that time frame and you realized what you did wrong, process your foods again. After the 24-hour rule, food must be tossed out because it’s not safe.

The other bad news is that not all foods handle reprocessing. If you didn’t add enough pectin to your jelly, that’s totally easy to reproduce, but if you didn’t can corn properly, another round in the pressure canner is going to do more damage than good.

Typically, the best foods for reprocessing are soft goods. Anything with a bit of crunch will lose it all during a second round in the canner.

Related: 8 Jam and Jelly Problems & How to Fix Them

So, what can you do to save the food if you can’t put it through the canner again?

Start Freezing!

The best thing to do is put those foods into the freezer.

For example, if you messed up canning green beans, simply take them out of the jars and put them in a freezer-safe container or bag. It may not be shelf-stable on the shelf, but at least it’s preserved for you to use later.

Avoid These Mistakes While Canning

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.

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  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 🙂

    2. I been canning salsa for three years now. I have a question…i just finished my canning Saturday morning…is it to late to wash the jars down with hot soapy water?

      1. Do you mean the jars are already full of salsa? If so, then yes, it’s too late to wash the jars. You should do that before you fill them with the hot foods.

    3. I want to can but I am afraid of botulism. This article helped me feel a bit more knowledgeable.

  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!

  7. Not filling jars properly is one of my sore spots. I see a lot of jars with an inch or more air space.

    I was given a jar of relish that was sealed with a piece of wax paper between the jar and lid. I emptied the jar into the trash. A sad waste but it couldn’t be helped.

    I shared this on Facebook and pinned it to multiple homesteading boards. The more people who read this the better.

    1. Thank you Robin! Yes, headspace is important. It’s okay if you do 1/2 inch if you needed 1/4 inch. But, I’ve seen people can jars of jam half full. That’s just too much air space.

      Oh my gosh, I can’t imagine using wax paper between the seals.. Goodness! Then again, sealing with parafiin wax was another common tactic.

  8. 1.) Thank you for the pH level threshold for water bath canning! I contacted the Ag Extension here for that info and they never got back to me! I wanted to make some tomatillo salsa that had lime juice as a acidifying ingredient. The Ball book only used lemon. After research, I found that limes are quite a bit more acidic than lemons.
    2.) The reason we need to add an acidifier, acid, lemon or lime to tomatoes is that in earlier days the tomatoes were much more acid than the engineered ones we have today.
    3.) I found some great recipies for canning plums, but they were all from New Zealand, and had some suspect methods. I just used our Ball methods but their recipes and everything was fine.
    If your Agricultural Extension is responsive, I suggest using them as a resource.

    1. I have been reading some recipes that just putting jars in canner to get them hot but not sterilizeing them?
      Thank you

  9. Ok, new to canning and starting to get the guidelines down….but i am confused on doing stewed tomatoes. I’ve seen recipes that had peppers, onions, celery and garlic and the canning methods were different. Which one is acrually recommend

    1. If I were to can stewed tomatoes – yummy, by the way – I would pressure can them. If you were just doing plain, diced tomatoes, water bath canning should be sufficient if you add lemon juice. The acid levels in tomatoes do vary, and the addition of low-acid foods to the recipe could make it more in the neutral range of acidity. Pressure canning would be the safest route, and one of the Ball canning books recommends pressure canning as well. I recommend that new canners grab one of their books so that you can feel confident in the recipes you use 🙂

    1. No, not really. Tomato sauce is an example of something that some people pressure can instead of water bathing. However, you don’t want to pressure can jams, jellies, pickles.. chutneys. The intense pressure and heat will cause the pectin in the jellies and jams to become runny, so your end product wouldn’t turn out well. It’ll make pickles mushy. It won’t create the texture that you want.

    1. A lot of people do, and it’s not a horrible practice. The main reason why you don’t want to leave the rings on in storage is because the lid could unseal and the pressure from the rings could either reseal the lid or hide the fact that bacteria entered your food. Leaving the rings off lets you easily notice that the lids are off or too loose.

  10. THANK YOU !!!!! This is well needed information, so many people dont realize how sick someone could get . I just started making jam and jelly about 4 years ago . I only use Ball and Better Homes and Garden cook books for canning , i have a hard time trusting non-tested recipies , i never take short cuts , dont trust them .

    1. It’s always best to use tested recipes. Canning safely is so important, especially when we’re feeding our friends and family. It’s not worth the risk!

  11. For all you more experienced canners still insisting that reusing lids, just heating contents, water bathing low acidic foods, and other out dated methods of canning, I have a simple question for you;

    Do you wear a seatbelt a vehicle?

    You see, I grew up not wearing seat belts. Then, the safety and common sense of changing those habits was reinforced by those around me, even though I never did get hurt or even know anyone who did die in a car accident. I often remind others to put their seat belts on in my own vehicle.

    The author of this post is merely encouraging you to practice safety in canning procedures. Why would anyone discourage that? If you are still stubborn enough to continue taking chances with botulism, you do you. Personally, I believe there are some things that aren’t worth the risk and killing people I love with food I’ve made isn’t one of them.

    1. Absolutely Rachel. I always say that we do better once we learn better. It’s not worth harming my kids because I don’t want to can correctly and responsibly. Honestly, it doesn’t take much time to can properly!

  12. Just bought a pressure canner to safely make spaghetti sauce without having to add lemon juice or ascorbic acid. Now I see in the recipe book I still need to add acid which to me ruins the taste. The canner recipe also requires sugar and I am wondering if that is also required to be safe.

    1. You need to follow the safe tested recipe exactly. It was tested for safety with those ingredients and processing times. The reason some of those recipes call for added acid is to allow a shorter safe processing time. Try using citric acid if you don’t like the lemon taste. Half a tsp for quarts and a quarter tsp for pints. You can always also add a pinch of sugar when you open the jar to heat and serve. There are some safe tested recipes for tomato products that do not require added acid, such as the stewed tomatoes recipe on the NCHFP website. Remember, NEVER omit acid called for in a recipe NOR think that simply increasing processing time will make it safe. It won’t.

  13. Hello, I’ve been canning for about 15 years. I am one of those people that “my grandma did this”. I believe I’m safe canning and agree with science to back up safe methods. Is there a book or books you would suggest for someone like me with old habits. I enjoy canning but I’d rather be safe. 😊

    1. Typically, anything by Ball I would recommend you read. Any Ball Canning Book would explain the safety measures to take during canning.

  14. Thank you so much for being an advocate for SAFE canning. I have had to unlearn 30 years worth of dangerous habits. I love Pinterest but have learned to scrutinize and many times stay away from canning recipes posted because they do not follow SAFE GUIDELINES.

  15. I am wanting to can spaghetti sauce. I have a very specific recipe that I cook. It is basically tomatoes (paste form, not diced), garlic, herbs and Italian sausage. I don’t want peppers and onions in it. I understand that it needs to be pressure canned. I understand that I shouldn’t have more than 1/2 inch headspace. How do I make sure that my recipe is safe for canning?

  16. You really need to be more specific on your making the statement that oven-canning is a no-no. I oven-can all of my flour, rice and dried beans. And as for milk, no you can’t heat milk and pour into jars. It still must be processed in a pressure canner. If you’re going to write a blog about canning, then don’t just skim over certain parts and make blanket statements. Do your homework and write a detailed entry.

  17. So, the canning recipes I’ve been using on Pinterest aren’t safe?!!!! I do believe some of them are safe!
    I water bath all my jellies and tomatoes. Pressure can green beans and non acidic veggies.

    1. Many of them are safe, but I’ve also seen sketchy things. I’ve found recipes that have you add butter to the recipe, which isn’t safe for canning. Take a close look at the recipe and make sure it doesn’t include anything on the do-not-can-list

  18. I recently canned several jars of tomatoe sauce and have about 3/4″ of head space. I follwed the directions for water bath canning and the jars pinged when the lids sealed. Should I be worried about there being too much head space. I am a first time canner.

    1. You should be fine! Next time, be sure to follow the indicated headspace on your recipe, but I’m sure your batch is fine 🙂

  19. Can you can leftover vegetable beef soup? Will it turn to mush since it’s already completely done?

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