6 Canning Safety Rules You Must Follow
* This article contains affiliate links. For more information, please read my Affiliate Disclosure.
Well friends, summer’s finally here, and that means canning season is upon us. This also means it’s time for a little refresher course on canning safety, because while this might not be the most exciting aspect of canning and preserving food, it’s definitely the most important.
Canning is a science, not an art.
You can’t just “get creative” with your home canning recipes the way you can with cooking. There are a number of safety rules you absolutely must follow to ensure a safe finished product for you and your family. Because why bother canning up your own food at home if it’s not even safe to eat, amiright?
I always find it a little shocking that there are people who push back against the recommendations that one should always follow proper, updated canning procedures when canning food at home, or who pride themselves on being “canning rebels.”
Often the protests sound something like “my grandma did it that way for years and never killed anyone, so I’m going to keep doing it that way,” or “I’ll take my chances [even though I’m well aware of the risks involved].”
Why risk your health or even your life? Or your family’s lives?
While home canning is a very safe and easy way to preserve food and enjoy the summer and fall bounty all year long, there are some very serious potential risks if you choose to play fast and loose with the following very basic and sensible canning rules.
So don’t be a rebel, mmkay? This is one aspect of homesteading (and life) where following the rules is cool. Because, as my dorky yet loveable husband would say “it’s cool to be safe!”
(I may make fun of him, but he’s not wrong).
Here are six canning rules you absolutely MUST follow to ensure your home-canned food is 100% safe to eat.
6 Canning Safety Rules You Must Always Follow to Ensure Safe Home-Canned Food
1. Always use a canner to can food at home
I know, this one seems pretty obvious, right? Well, apparently not to some people who still think it’s safe to can food in the oven, or using the open kettle method or the inversion method where you just put the hot food in the jars and let the lid seal, either right-side-up (open kettle) or upside down (inversion).
Sure, you might get your jars to seal this way, but none of these methods work to kill all of the harmful bacteria that you’ve now sealed up nice and tight inside your canning jars.
You absolutely must use either a water bath canner or a pressure canner when canning food at home
In fact, if you’re water bath canning you don’t even technically need to use a water bath canner, you can just use a large stockpot with a rack in the bottom. But you must either process your jars in a boiling water bath or in a pressure canner, depending on what you’re canning.
Learn more about how to get started water bath canning, or how to pressure can foods safely
Which brings me to my next safety tip rule…
2. Low acid foods must be canned using a pressure canner
This is pretty much the rule to end all rules when it comes to canning safety, it’s that important.
While high acid foods like fruits, jams, jellies, pickles, pie fillings, etc. can all be water-bath canned, all low acid foods MUST be canned using a pressure canner.
Low acid foods include things like meat, vegetables, fish, soups, stocks, combination meals, etc.
While a boiling water bath canner reaches temperatures high enough to kill off most harmful bacteria in food, only a pressure canner can reach temperatures high enough to kill off botulism spores, which can produce a toxin under the right conditions if they’re not killed or rendered inactive by the high heat inside a pressure canner.
While there are botulism spored on everything (and I mean EVERYTHING, from fruits and veggies to soil and water, they’re everywhere…), in most cases these botulism spores are inactive and therefore, completely harmless.
However, given the right conditions and the right environment, these spores produce a powerful neurotoxin that can seriously harm or even kill you. Wanna take a guess what those conditions are??
Botulism thrives in a moist, low-acid, anaerobic (low or no oxygen), room temperature environment. Yup, the exact conditions inside a jar of home-canned food.
It’s imperative that all low-acid foods be pressure canned in order to kill the botulism spores off before they have a chance to turn deadly, so this rule is a really important one.
You can learn more about botulism and how to stay safe canning low-acid foods here.
3. Some foods should never be canned
There are some foods that should never be canned, even with a pressure canner. These foods are:
- Eggs and Dairy (milk, cheese, butter, etc. and eggs, including pickled eggs)
- Pumpkin purée (puréed pumpkin or winter squash, ie. acorn, butternut squash, etc. are too thick, even for the high heat of a pressure canner to permeate. Pumpkin and squash must be cubed and pressure canned..)
- Flour, pasta, rice, cornstarch, arrowroot powder, etc. (more of a quality issue than a safety issue as they will get mushy and clumpy)
- Oil (olive oil, avocado oil, coconut oil, etc. A little bit of oil in a tested canning recipe is okay, but oil based foods like pesto or sun-dried tomatoes in oil should never be canned)
- Nut butters (ie. peanut butter, almond butter, sun butter, etc.)
Dairy is a big no-no when it comes to home canning. If you ever see a recipe for how to can milk or butter at home, RUN the other way!!
You can freeze dairy. You can even ferment and dehydrate some forms of dairy. But you can never can it. Since dairy is low-acid and high in fat (which can protect spores from being destroyed by heat), there’s just no safe tested method for canning dairy products at home.
* You may come across jam recipes calling for tablespoon or so of butter. This is okay and is meant to help with the foam on the top of jam. But as far as canning a stick of butter, just don’t.
Pumpkin purée is another thing that should not be canned because the purée is too thick for even the heat of a pressure canner to penetrate and kill all of the harmful bacteria.
You can can cubed pumpkin or winter squash in a pressure canner, then when you’re ready to use it you can drain it and purée it. But if you want to purée it ahead of time the only safe way to preserve it is by freezing.
Flour, pasta, rice, cornstarch and arrowroot powder are also things that should not be canned. This is more of a quality issue than a safety issue, but it can cause your food to be essentially inedible, so you’ll want to heed this rule too.
This is because flour and starch products break down over time and become mushy and gross. So for example, if you want to pressure can up some chicken soup, you can totally do that, just don’t add the noodles. Cook the noodles fresh when you’re ready to serve the soup. Dried pasta noodles can be stored pretty much indefinitely, so there’s really no need to can them with combination meals. Same with rice.
Likewise, adding flour, cornstarch and arrowroot powder to recipes as thickeners might work fine when you’re cooking them fresh, but not for canning. One obvious example of this is home-canned pie fillings.
While you might add one of these thickeners to your pie filling to thicken it when you’re baking it fresh, adding it to your home-canned pie filling can result in a lumpy, runny mess that you really don’t want to eat.
For pie fillings, the only approved thickener for canning is Clear Jel. It’s a modified cornstarch (non-GMO, so don’t worry) that can withstand the high temperatures of canning and keeps your home-canned pie filling thick and delicious for a long time.
I’ve had pie filling on my shelf for two years before and when I opened it it was as good as when I packed it in the jar. That’s thanks to Clear Jel!
You can see how I use Clear Jel in my recipes for home-canned blueberry pie filling and home-canned cherry pie filling.
4. Use Mason jars for canning
This one might seem like another obvious one, but I’m always astounded at how many people think it’s safe to can food in old jars from the grocery store (including some people in my own family, *ahem*).
You can’t guarantee a good seal when you reuse old grocery store jars and lids and this can mean food spoilage in the end.
And because they’re all different sizes they don’t always fit the Mason jar lids, which are the only lids approved for home canning.
You can reuse Mason jars and bands though, and you can usually even find old ones really cheap at thrift stores and garage sales. That’s totally fine, as long as they’re actually Mason jars and they’re not super old.
(Some really old Mason jars don’t fit today’s lids, and they’re more likely to crack and break due to age. These vintage jars are better as a collector’s item than an actual canning jar).
Otherwise you can reuse jars over and over again so they’re really economical (and environmentally friendly!). So even if you have to purchase them new up front, you’ll get your money back over time.
5. Always use new lids when canning
While you can totally reuse Mason jars and bands, you can’t reuse the lids. This is because canning lids are made to seal only once. Once they’ve been sealed on a jar, their seal is compromised and they can’t be guaranteed to seal again.
Even if they do seal again, the seal might not be strong enough and it might break and cause your food to spoil.
Again, for the price of purchasing new lids every canning season, it’s not worth it to try to save a few pennies by reusing them.
Plus, you can still reuse old canning lids for all sorts of other things. I keep mine and use them or storing dried goods in my pantry, for making (and labelling) homemade products like candles, body butters and bath salts, etc., or for storing food in the fridge in Mason jars (ie. extra food from a canning project, homemade mayo, yogurt parfait or overnight oats for my daughter to take to school, etc.
If you want lids you can reuse, you can invest in some Tattler lids. They’re a little more costly up front but can be reused over and over again.
6. Always follow a safe and tested recipe
There are a lot of unsafe canning recipes and advice floating around the Internet. Likewise, there are a lot of unsafe and outdated canning recipes and practices that have been passed down through generations. And while some people make the argument that they’ve used these recipes and methods before and are still here to tell the tale, I don’t really think that’s the most reassuring piece of evidence to support a safe canning recipe, do you?
The fact is, a lot of research has been done on food safety and what scientifically makes home-canned food safe (or unsafe) to eat. Back in our grandparents’ day, a lot of this research hadn’t been done yet and this information didn’t exist. But just like with every other scientific advancement in history, we’ve evolved since then and our understanding of bacteria and food safety has come a long way.
Still, not everyone has caught up with the times or chooses to believe in the science behind food safety, and anyone can post anything on the Internet, so beware that recipe for canning milk that you might see on Pinterest or the recipe for water bath canning green beans (non-pickled ones) that your meemaw passed down to you.
Always follow safe, tested and up-to-date canning recipes and practices to ensure a safe finished product.
Some good sources include the National Center For Home Food Preservation (the authority on home canning in North America), anything published by Ball/Bernardin (Ball is the maker of most Mason jars you’ll find on store shelves in the US and Bernardin is the Canadian version) and of course, my collection of canning recipes right here on this site (all of my recipes are taken or adapted from one of the aforementioned sources).
You can check out the National Center For Home Food Preservation site here for pretty much anything you want to know about canning and preserving food at home, as well as many recipes.
I also recommend getting yourself a solid canning book full of safe, tested recipes. My favourite is the Ball/Bernardin Complete Book of Home Preserving.
I also compiled 30 of my favourite canning recipes (all adapted from trusted sources such as those mentioned above) in my Home Canning Handbook (eBook), which you can grab right here. And of course you can also check out all of my free canning and preserving recipes right here.
Ready to take your canning game to the next level?
Whether you’ve never canned anything before or you’ve done a little canning and you’re ready to take the next step, my Yes, You CAN! complete home canning course will walk you through everything you need to know to get started canning food SAFELY at home.
Over the course of 12 easy-to-follow lessons, we cover both water bath canning and pressure canning, and I show you step-by-step how to can your own jams, jellies, pickles, pie fillings, fruits, vegetables, tomato sauce and chicken stock at home. And of course we’ll go over canning safety, equipment and over all best practices in more depth so that you always feel confident both during the canning process and while enjoying your home-canned food afterwards.
You’ll also get a collection of bonuses including:
- Printable checklists and cheatsheets to help you stay safe and never miss a step while canning food at home
- My bonus Jam and Jelly Making Mini-Course to help you make and can your own jams and jellies with store-bought pectin, no pectin and even low-sugar
- A copy of my Home Canning Handbook, complete with 30 of my favourite home canning recipes for canning everything from fruits and vegetables to jams and jellies to sauces and salsa to stocks, soups, meats, combination meals and more!
But the best part is that, I’m currently offering my Yes, You CAN! home canning course for 25% off the regular price, but only for a limited time!
So if you’re ready to get started canning (or canning more food than ever before this year!) enroll now to take advantage of this special offer and get started stocking your pantry right away!
I hope to see you in class!
Wishing you homemade, homegrown, homestead happiness 🙂
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I have a corn allergy and can’t use clearjel. Are there any options for me in canning pie fillings, or do I just can the fruits with the seasonings for pie, and thicken it before putting it in the crust??
Yes that’s exactly what I’d do. Just omit the Clear Jel and add your flour thickener to your pie filling just before adding it to your pie:)
I have a harrisa recipe I make, I would like to can it, but it seems to be unclear. It contains alot of acid and I’ve checked the pH level which is 4.4 but it also contains alot of oil. Does this automatically make it unsafe to can despite the pH level? It’s also not cooked, but rather a fresh sauce. I’m really struggling to find the information I need, so any help would be appreciated. Many thanks
I definitely wouldn’t can it if it has a lot of oil in it. Also, as it’s not a tested recipe, it’s impossible to know the exact PH and how much acidity you would need to ensure it’s safe for waterbath canning.
If you’re pressure canning you can start to make your own recipes with more ease as you simply process according to the ingredient with the longest processing time, but with waterbath canning it’s trickier.
I would stick to freezing it to preserve it just to be safe.
This was VERY informative and helpful. Thank you!!