20 Common Canning Mistakes You Need to Avoid
The good news is that the fall canning season is now in full swing!
The bad news?
I have VERY little time to do anything else...including the time to update this blog. As a result, it’s been a couple of weeks since my last post, and I apologize.
With all that out of the way, let’s talk canning. I absolutely love preserving my own food - whether I’m canning, freezing, fermenting, pickling, dehydrating...there’s just something special about spending time stocking away food for the rest of the year.
Our garden was very productive this year (something I’m extremely grateful for after all of that watering, mulching, and fertilizing!) and as a result, we’ve been flying through our canning jars like crazy, trying to get everything up on the shelves.
We’ve made our fair share of canning mistakes from time to time, and while most of them are harmless, there are some that can be downright dangerous. If you’ve just started canning your own food at home, these are the mistakes you don’t want to make while you’re getting started.
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How Do I Know if I Canned Correctly?
Canning can be a great way to preserve your harvest, but it's important to do it correctly. If you're not sure whether your jars have sealed properly, here are a few tips to help you out.
First, make sure that you've followed the directions for canning carefully. If you're not sure whether you've done something right, it's better to start over than to risk ruining your food.
Next, take a look at your jars after they've been sealed. If the lid is bulging or popped up, that's a bad sign. Also, tap on the lid of the jar. If it makes a popping sound, that means the seal is good. However, if you don't hear anything or the lid feels loose, that's an indication that the seal has failed.
If you're still not sure, open up the jar and take a look at the food inside. It should be free of mold or spoilage. If everything looks good, then your canned goods should be safe to eat. Otherwise, it's best to discard them.
By following these simple tips, you can be sure that your canned goods will be safe and delicious.
Not sure if your jars have sealed? This is important to know, since sealing is the only way your jars will last in storage. Here’s a video you can watch with some things to look for:
1. Not Following a Recipe
I love experimenting with new recipes and tweaking them to suit my preferences. So - it can be seriously hard when I have to follow a recipe exactly when it comes to canning.
However, it’s important that you let go of these tendencies when you bust out the canner. Why? Failing to follow a tried-and-true recipe when you are canning can result in some serious health risks. When you can, you are engaging less in a culinary art than in an exact science. You need to make sure the recipe you are using has been tested and approved.
That’s according to the National Center for Home Food Preservation, too - so I’m not just up on my soapbox here.
2. Using a Boiling Water Bath Canner When You Really Need a Pressure Canner
There are lots of foods that can safely be canned. But not all foods can be canned in a water bath canner.
I get it, I really do. Water bath canners are so much quicker and easier to use, plus you don’t have to worry about any of the common fears that people have about pressure canners exploding and what not.
And I understand - I still refuse to pressure can by myself. However, because certain foods can only be canned in a pressure canner due to their low acidity, you really don’t want to risk making yourself sick by taking the easy route out and using the water bath canner.
Here is a list of foods that should always be canned in a pressure canner. Make sure you familiarize yourself with it!
And don’t forget about these foods that should NEVER be canned under any circumstances.
3. Not Adjusting for Altitude
If you’re one of those lucky folks who lives way up in the mountains, guess what? You can’t follow a canning recipe verbatim. You need to make sure you adjust for altitude. That’s not as complicated as it sounds - usually, you just need to add time or pressure to your recipe, depending on what method you are using to can.
Here’s a handy guide to help make things easier.
4. Overfilling Your Jars
Make sure you leave plenty of headspace. The headspace is simply the area between the stuff that’s inside the jar and the lid. If you want a vacuum seal, you need to avoid overfilling your jars. If your jars have too much food inside them, the food might spill out during processing. Any grease, seeds, pulp, or other food on the rim of the jar can prevent an airtight seal from occurring. FYI, this is also why you want to wipe your jars down before you put them in the canner!
The amount of headspace you need to leave will vary depending on the type of food you are processing, but generally, a one-inch headspace is plenty of room.
5. Reusing Canning Lids
Always, always, always use new canning lids when it comes time to can. You can recycle the jars, you can recycle the bands, but you can’t use the lids.
It might not seem like there’s anything wrong with them, but after the lid has been used just one time, the plastisol seal will be spent. You can’t reuse it or you’ll risk sealing failures - sometimes, you won’t even know that the seal has failed until it’s too late.
Play it safe and reuse your lids for other purposes - like gardening labels (check these out!) or non-canning-related food storage. You can get lids super cheap on Amazon, so there’s no reason to try to save a few pennies by reusing them.
6. Using Damaged Jars and Bands
Don’t try to use a jar with a tiny nick in it, or a rusty old band. Sometimes, you might be fine. Other times, you might end up with a canner full of broken glass. That’s not fun - and jars and bands are so cheap, there’s no reason to cut corners here.
Here are some high-quality jars and bands for you to consider.
7. Not Using Enough Water
Read your recipe carefully to find out how much water you should be using. While you’re prepping your canner and ingredients, you might find that your water level drops off. When you add your jars, you will want to add more boiling water so that it’s at least one to two inches above the jar tops. When you’re processing for over thirty minutes, the water should be two to three inches above the jars. And remember, don’t start your timer until you have a boil!
8. Using Poor Quality Ingredients
I’ve said it before and I’ll say it again - the quality of your canned goods will only be as good as the quality of your ingredients. If you use rotted, moldy produce, your canned goods are going to be rotted and moldy. Make sure you only select the best products and maybe leave the inferior produce to your chickens and pigs.
9. Substituting Fresh Lemon Juice for the Prepackaged Stuff
This was something I never knew until this year. I always thought you could swap actual lemon juice for bottled lemon juice. It has to be healthier and have a better flavor, right?
Wrong, unfortunately. When you use fresh lemon juice, you are compromising food safety. Bottled lemon juice has to have a consistent pH level, while fresh lemons will vary from fruit to fruit. If you’re adding lemon juice to a recipe that needs it in order to be safe for canning, you’ve got to stick to the storebought stuff.
10. Wasting Time by Warming Lids
You’re not going to get sick if you don’t warm your lids before placing them on your jars. I always thought you had to preheat the lids (as well as the jars) before using them in canning. However, this is more of a time-waster than anything else. While it’s perfectly safe to warm your lids, it’s not necessary by any means. Do still heat the jars, though!
11. Using Metal Utensils to Get Rid of Air Bubbles
First of all - make sure you remove air bubbles, people. Removing air bubbles helps reduce headspace, because too much headspace can cause your seal to fail. So make sure you do it!
However, try not to use a metal tool to do so. While it’s fine in most cases, using a metal tool can etch the inside of the glass, leading to an increased risk of jar breakage. Stick to plastic or wooden tools instead!
12. Using a Too-Large Jar
When you are selecting jars for canning, make sure you pay attention to the processing times on your recipes. Remember that larger jars require longer processing times, so if you’re swapping out jars in your recipe, you will need to adjust the time, too. You can safely go down in size without changing the processing time, but you can’t go up.
13. Recycling Jars That Aren’t Made For Canning
It’s all too tempting to try to reuse jars that aren’t supposed to be for canning. I’m looking at you, you penny pincher!
If you try to use old containers, whether they’re glass, plastic, or some other material, that aren’t designed specifically for canning, you’re going to regret it. These jars aren’t built to withstand the heat and pressure of the canning process. Best case scenario, you’re going to have a mess to clean up in your canner when a jar breaks. Worst case, you’re going to get botulism. Don’t risk it.
14. Over- or Under-Tightening Your Lids
So, it’s important to tighten your rings and lids when you can. You surely already know that. However, did you know that it’s possible to over-tighten them? To avoid this, simply use your fingers to screw bands down until there is a slight bit of resistance - not too much.
Don’t try to tighten the bands using the full strength of your hand. This can cause air to fail to vent out of the jars, which can damage your lids and cause a seal failure. Don’t panic if your rings seem loose after canning. This is normal. You just need the lid to seal.
Whatever you do, don’t try to tighten the bands that have come loose immediately after you’ve finished processing the jars, either. This can disrupt the seal that is forming and halt the process altogether. In fact, you really don’t need to leave the rings on after the jars have sealed, anyway - you can always remove them to be used for canning other jars, too. They’re only there to help keep the lids on during the canning process.
15. Canning On an Unsuitable Glass-Top Stove
Some glass stoves aren’t designed to be used for home canning. You need to make sure your canner has a smooth bottom and that it’s no more than one inch wider than the burner.
Canning on a glass stovetop that is not designed for canning can cause your stovetop to break. It can also cause food spoilage, as your canner might not be heated evenly.
There are plenty of good canners out there that are suitable for a glass-top stove, though. Check out this one, here - it’s supposed to be safe for glass top stove canning.
16. Baking or Freezing in Mason Jars
There are a ton of awesome freezer recipes out there for mason jars. There are also plenty of recipes for baking.
However, you need to be really careful about which jars you use for this purpose. Not all wide-mouth jars can be used for freezing because the contents inside will naturally expand, which can break certain types.
You can tell if your mason jar is freezer-safe by looking at the neck. If the neck has “shoulders”, you cannot put it in the freezer.
When it comes to baking, you need to know that baking is not recommended at all in canning jars. These jars are not made out of tempered glass and so they can crack under extreme heat.
17. Placing Hot Jars Directly On Your Counter
Whoops - I’m definitely guilty of this one. Before we bought our farm, my husband and I were canning tomatoes one fall and just idly put a few finished jars on the kitchen table.
We didn’t put anything underneath them.
Now our table has some seriously unsightly rings that we will never, ever be able to get rid of.
Not only can placing hot jars on unprotected surfaces damage your counters and tables, but it can also break your jars. When your countertops are chilled and you place hot glass jars on them, the temperature differential can cause thermal shock and breakage. Make sure you put your jars directly on a towel and not in the fridge (or in the pathway of a heavy draft) to prevent this from happening!
Similarly, make sure you don’t put a cold jar into a hot water bath. Always give the two time to acclimate to each other.
18. Not Keeping an Eye on Your Canner
Regardless of whether you are using a pressure canner or a water bath canner, it’s important that you keep an eye on it at all times. You don’t want a runaway boil to get away from you, nor do you want the pressure in your pressure canner to get so high that you are creating, in essence, a miniature bomb.
Now is not the time to be working on your taxes or taking a nap. Keep an eye on that canner at all times! And if you’re accident-prone, maybe keep a fire extinguisher handy, too.
That’s a joke. Unless you’re really accident prone, of course.
19. Ignoring Processing Times
Pay close attention to the processing times on your recipe of choice. And don’t cut corners! Removing even a minute from the processing time can affect food safety, and trust me, it’s not worth it.
20. Not Canning at All
I know, lame tip, right? But we had to get to an even twenty.
That, and I think it’s really important to include this one. A lot of people shy away from home preservation because they are so scared of the what-ifs. What if I make a mistake? What if the food turns out to be disgusting? What if, what if, what if.
But don’t let fear get the best of you. There’s lots to love about home canning, and once you learn the ropes, those fears will subside - believe me.
So what do you think? Are you ready to dive into the exciting world of home food preservation? Let me know your favorite recipes and tips in the comments!
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