10 Canning Mistakes to Avoid

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This year there are many new canners out there. How exciting!! It is a wonderful to take charge of your own preservation. When canning it is important to know the rules and follow them. I am a stickler because it matters! Here are 10 canning mistakes to avoid. 

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Mistake #1 Following untested recipes or making up your own recipe

Most of the recipes online from bloggers like myself have NOT been tested for safety. That doesn’t necessarily mean they are unsafe but you need to know who to trust. In general don’t recommend using google to find a recipe.

I prefer to use a published book, the majority of the time this is someone who has been canning for many years and knows how to create a safe recipe. If it is a book from someone I’m not familiar with, I’ll check their recipes against a tested recipe.

 In cooking you can tweak things here and there with no consequence but when it comes to canning you need to follow a tested recipe. 

Why? The short answer is botulism- a deadly form of food poisoning can happen in improperly canned food. 

For the long answer please refer to THIS GUIDE on canning food safely. I recommend all new canners read this. It is the best guide I have read.

So what recipes should you use? Here are my recommended canning recipe resources:

+Recipes published by Ball canning. All recipes in their books have been tested for safety. Below are some of my favorites.

+I also recommend recipes from the National Institute of Food and Agriculture. They are tested and can be found HERE.

+Ball Canning also has some recipes online that are available for free. You can find them HERE.

+Marisa McClellan who writes the books I mention below has an blog and publishes some of her recipes there. To check out her recipes click HERE.

Here are some other books I trust:

Click image to link to the books

When you’re not sure if a book is tested or following recommended guidelines, you can always compare it to a similar recipe in the Ball Book of Preservation or National Center for Home Preservation.

Mistake #2 Changing the ingredients and amounts, or processing time in a canning recipe.

As I mentioned above, you shouldn’t change the ratio of acid to vegetable in a canning recipe for safety reasons. Botulism grows in low-acid environments. When you tweak amounts in a recipe it changes acidity. 

Any changes which can be made that will not affect the safety of the end product are usually mentioned in the notes of a tested recipe. 

Time for processing a canned product also shouldn’t be changed. Even if the food is acidic enough to be free of botulism growth, there are other bacteria present that need to be killed off to ensure a safe product.

Mistake #3 Flipping the jars upside down to seal lids

This is an old practice that is not safe. Just because grandma has done it for years without any problems doesn’t mean it’s ok to do. 

I think the idea was that the inversion creates a stronger vacuum seal. With modern canning lids this practice is not necessary and quite frankly shouldn’t be used.

The worst mistake is when cans are flipped immediately after filling jars, and no heat processing happens. 

As I mentioned above the water bath or pressure canning processing times ensure harmful bacteria are killed and do not spoil your food or poison you.

Mistake #4 Not Restarting the processing time if the pressure canner drops below the pressure needed for a recipe.

When you are pressure canning a food, the pressure needs to stay at or above the recommended pressure for the entire processing time.

If the pressure drops below the necessary, you need to get the pressure back up where it should be and restart the timer for the entire processing time.

Mistake #5 Not adjusting canning times and pounds of pressure for altitude 

The altitude of your location makes a difference in the temperature of the water. All canning recipes have recommendations for sea level canning. 

You need to make adjustments if you are at 1000 feet and above. When you get to higher altitudes you need to increase processing times in water bath canning. In pressure canning you need to increase pounds of pressure for higher altitudes.  

Here is a link to the adjustments that need to be made based on your altitude.

https://nchfp.uga.edu/how/general/selecting_correct_process_time.html

Mistake #6 Canning Foods that aren’t recommended for Canning

Some canning products that used to be safe are no longer recommended for home canning. And then there are foods that have never been safe to can.

Do NOT can:

• Butter
• Milk
• Pumpkin Puree
• Popcorn
• Dry Foods
• Chocolate Sauce

I’m sure there are more but that is what I can think of off hand.

Mistake #7 Adding thickening agents not approved for canning.

Do not can anything with flour as a thickener. It can not stand up to the heat of canning and will get lumps and a gummy texture. 

The approved substitute for thickening is a product called Clear Jel. It’s a modified corn starch that can handle the heat of canning. I personally choose not to use modified food starch. You can omit it from a recipe if you choose and thicken canned food after opening a jar to serve.

And from National Center for Home Food Preservation they say:

“Do not add noodles or other pasta, rice, flour, cream, milk or other thickening agents to home canned soups.”

If you want to add any of these the best practice is to add them later when the jar is opened for serving.

Mistake #8 Using homemade lemon juice or vinegar in when it calls for commercially produced

I’m all for homemade everything but in the case of canning sometimes you need to use store bought to ensure safety. Most vinegars in the US are at a level 5% acidity. Canned store bought lemon juice also has a certain acidity that is the same across the board. 

When it’s home squeezed lemon juice or homemade vinegar the acidity amount can vary a bit and even though you are adding the same amount a recipe calls for, your homemade product may not be acid enough to make it safe. 

If a tested recipe calls for fresh lemon juice, by all means use it! I do! Generally tested recipes that allow the use of fresh lemon juice do so more for flavor in an already acidic product.

Mistake #9 Adding cold jars to hot water and other thermal issues

Before canning, jars should be sterilized if it is a processing time less than 10 minutes. The jars still need to be heated if the processing is longer than 10 minutes but not necessarily sterilized. 

This usually isn’t too big of an issue, put jars in cold water and then heat up and remove from the canner. After that they are ready for filling.

The problem comes when you are doing multiple batches of jars and need to heat the next batch of canning jars. When the water is already hot from the previous batch and the cold jar goes in the water the bottom of the jar will break off in one clean piece usually.

I know this from experience. Haha!

Instead empty the hot water from the canner and fill with room temperature water then put your jars in and heat. It is an easy fix.

By the way, dry heating the jars in the oven to ready them for filling also isn’t recommended. It’s not necessarily a safety issue from what I’ve read, just that there is a risk of jars exploding in the oven. 

Using the dishwasher to heat and sterilize jars in preparation for canning is safe. This is a good option for big batches of jars. 

Another issue is raw packing fruits or vegetables and not heating the jars at all prior. You need to heat the jars whether it is raw or hot pack. And for raw pack you usually pour over boiling liquid so the jar needs to be warm so it doesn’t break.

Mistake #10 Not checking jars for cracks, chips, and scratches

A common place for chips and nicks on the jar is the top lip. Any chips in the glass on the top can cause seal failure in the lid. 

A crack in the glass, even a small one, can lead to a broken jar in the canner. It’s especially devastating when it’s full of food and your hard work! 

Before I fill my jars, I do a good check of the jar all over. But I pay special attention to the top lip and run my finger across the entire top to check all is as it should be.

Conclusion:

10 Canning Mistakes to avoid are:

• Mistake #1 Following untested recipes or making up your own recipe.
• Mistake #2 Changing the ingredients and amounts, or processing time in a canning recipe.
• Mistake #3 Flipping the jars upside down to seal lids.
• Mistake #4 Not Restarting the processing time if the pressure canner drops below the pressure needed for a recipe.
• Mistake #5 Not adjusting canning times and pounds of pressure for altitude.
• Mistake #6 Canning Foods that aren’t recommended for Canning
• Mistake #7 Adding thickening agents not approved for canning.
• Mistake #8 Using homemade lemon juice or vinegar in when it calls for commercially produced.
• Mistake #9 Adding cold jars to hot water and other thermal issues
• Mistake #10 Not checking jars for cracks, chips, and scratches

I hope that list helps you avoid any potential problems. Canning is fun and worth the effort. Just make sure you are safe. Happy canning!