After the COVID 19 pandemic and food shortage scares gripped the country, gardening and food preservation experienced a resurgence of interest. Seed companies had to temporarily shut down their websites to keep up with demand, and many seed varieties are still out of stock. Now, as harvest approaches, store shelves are bare of canning supplies. Canning lids, which are usually around $4 or less at retailers, are being sold for double that price on Facebook Marketplace and other community resale sites.
With the renewed interest in home canning comes bloggers and social media influencers sharing delightful and delicious canning recipes. Some contain sources and links to the original recipes which were completely and thoroughly tested by reputable sources. Others…do not. Millions of new canners will be relying on the internet to deliver safe recipes to use with their fresh produce…and some of them may become seriously ill or even die if they choose the wrong recipe.
Canning & Botulism
Botulism is one of the most lethal toxins known to humans, but luckily the illness is rare and only thrives under certain conditions even though the bacteria that cause the illness are found naturally throughout our environment. Botulism bacteria enjoy a low oxygen, low acid environment. If given the proper conditions, such as in improperly processed home canned foods, Botulism sickness can cause difficulty breathing, paralysis, and death if it goes untreated.
The symptoms of botulism include:
- Double or blurred vision
- Difficulty swallowing
- Difficulty breathing
- Weak muscles
- Drooping eyelids
- Slurred speech
- Dry mouth
- A thick-feeling tongue
Untreated, Botulism has a 50% mortality rate, and even treated the mortality rate is still 3-5%. Treatment usually requires hospitalization and intensive care. Even after recovery, victims might experience fatigue and shortness of breath, which may require therapy.
Symptoms usually occur within 18-36 hours of consuming a contaminated food. You can read more about Botulism on the CDC’s website.
Following a tested and approved recipe from a reputable source virtually eliminates the risk of Botulism. Each recipe has been thoroughly tested to find the correct acid level and processing type and time to destroy the spores. Deviating from the recipe can result in the perfect conditions for Botulism to thrive in your canned food.
Where Can You Find Reputable, Tested Canning Recipes?
There are plenty of reputable resources and recipes online and at your local bookstore. For beginners, a great place to start is these places:
- The USDA’s home canning division
- The National Center for Home Food Preservation
These are going to have all your basic recipes, although I’ve sometimes found the directions a bit vague. I like these sources for plain vegetables with no fancy frills. Although the recipes can sometimes be vague on the technicalities, if you read your water bath or pressure canner manual and understand how to operate it correctly, you should be good to go.
For recipes that are bit different and incredibly beginner friendly, you can try the following:
- Ball Blue Book (US)
- Bernardin Guide (Predominantly Canada)
These two are mason jar manufacturers (owned by the same company, actually) that have their own private test kitchens, and their recipes are mostly the same. Personally, I use the Ball Blue Book often for pickles, novel jams and jellies, and other “frilly” recipes, although they do have some plain items. I feel like they add very specific directions to each recipe and write them as if it’s your first time canning. The beginning of each section includes additional information on prep and processing, as well. As you improve your canning skills, you can try out the Ball Complete Book of Home Preserving and the Ball All New Book of Canning and Preserving.
For more information on what is considered a reputable source, check out Healthy Canning’s website. I spent a lot of time on this website learning about different reputable sources I could trust in my canning journey. It includes a list of private authors who are considered reputable and recipes found on seasoning packets (like Mrs. Wages), as well.
How to Spot a Bad Recipe
Once you know what to look for, you should have no trouble spotting a recipe that you most definitely should not use.
First, RUN from any recipes that process jars using the following methods:
- Dishwasher Canning
- Crockpot Canning
- Microwave Canning
- Oven Canning
- Solar Canning (what?)
- Pressure Cooker Canning (such as an Instapot)
These methods are entirely unsafe, even for high acid foods like fruit or pickles. Although these methods might be hot enough to create a vacuum and get a seal on your jar, the heat and heat distribution is insufficient to kill the bacteria that cause Botulism and other nasty microorganisms.
These unsafe methods are usually “created” because people want convenience, or perhaps they don’t want to purchase canning supplies. It’s important to remember that there is no substitute for safe canning. Sure, using these methods may save you some time or money….or they might make you incredibly sick and land with with hefty hospital bills.
Avoid any recipes that claim the following:
- “You can water bath can in place of pressure canning.” (No, you absolutely cannot)
- “They say you shouldn’t do this, but I haven’t gotten sick…” (Dumb luck)
- “I developed this recipe myself.” (They likely developed a delicious way to earn a hospital visit)
- “This is grandma’s recipe!” (Old ways aren’t always the best ways. Safety standards change, and you should always use a current, reputable recipe)
Be especially cautious if a recipe calls for the following ingredients:
- Pureed Pumpkin or Squash (although cubed is fine)
- Broccoli or Cauliflower
- Pasta or rice (or any grain, really)
Although small amounts of oil, flour, or cornstarch might be used in a recipe from a reputable source, you generally should never try to can the above ingredients. They either break down and are gross, the fat content protects the Botulism spores, scientists have never been able to find a recipe that guarantees the destruction of Botulism spores, or a combination of all three.
Thickeners like flour and cornstarch cannot hold up to the high heat of processing, so it’s recommended you follow a recipe that uses a product like Clear-Jel, which the USDA has approved for home canning, or add thickener after you’ve opened the jar and are ready to use it. I can never find this stuff at my local grocery store, but you can find it online. I buy mine from Amazon.
You should also proceed with caution if a recipe DOES NOT contain the following information:
- A link or reference to the original lab tested recipe
- Processing times
- Jar size
Any recipe you find on the internet should include a link or reference to the original recipe. I love following recipes from bloggers who have made the recipe a few times because they provide photos of prep and processing, tips and tricks, and more specific information that I feel many recipes from reputable sources lack, but I will not use them if I can’t find the original, tested recipe.
Failing to add processing times or jar size might simply be an oversight, but those are two very important aspects to any canning recipe! If the there is a link to the original recipe, it’s no problem to find the information yourself, but if the recipe is missing all three of the above items, it’s best to move on!
As an additional note, it is generally safe to add dry seasonings to your canned foods as long as they don’t change the consistency of the product. For example, you might add salt and pepper to a jar of pressure canned vegetables to increase their flavor. Some people add mace or nutmeg to beans, or perhaps some additional cinnamon to their apple pie filling. Unless otherwise specified, adding dry seasonings and spices (never fresh!!) is the only acceptable tweak to a reputable canning recipe.
So, if you find a blogger’s recipe for cream style corn where she says she likes to add a dash of cayenne pepper for a kick, but otherwise follows the recipe provided in the Ball Blue Book, that’s okay. If she says she adds butter and fresh rosemary, but otherwise follows the recipe provided in the Ball Blue Book, that’s very bad!
Other Items of Note
Finding and following a reputable recipe is 80% of the canning battle, but some internet canners still use outdated or plain bad practices. Read below to see some of the most common mistakes and practices that are no longer necessary.
Boiling Lids for Sterilization
In the past, canners would have to boil lids to sterilize them and “activate the glue” that seals the lid to the rim of your jar. It is not recommended as it could actually damage the lid and cause a broken seal. Read the back of your pack of lids for specific manufacturer directions, but Ball and Kerr definitely do not want you to boil your lids!
This practice has persisted, though, and I made the mistake of boiling my lids when I was in the early days of learning how to can after watching a few YouTube tutorials. After about a month of storage, the seals on 80% of those first few batches broke, and I had to throw away the contents. Now, I only wash my lids in hot, soapy water, rinse well, and allow to air dry on a clean towel.
Boiling Jars for Sterilization
Although boiling your jars before using them won’t hurt, it has been found to be unnecessary. If your processing time in a water bath canner is more than ten minutes, you do not need to sterilize your jars. You do not need to sterilize jars that are to be pressure canned. The processing will sterilize both the jars and your food. If your processing time in a water bath canner is less than 10 minutes (which you don’t see too often) you can easily increase it to 10 minutes without risking the quality of the food. If you’re using lids that say you should not boil them, this is what you have to do, anyway.
If you’re packing hot food into jars, however, you should still heat them up to avoid breakage, but there is no need to boil them. I wash my jars in hot soapy water (or in the dishwasher if I have time), then simply place them in the water I’m heating for canning to get hot if I’m packing them with hot food.
Storing Canned Foods with the Bands Screwed On
Once your food has cooled and seals have set, you should remove the bands from the jars before moving them to storage. Leaving the bands screwed on could cause a false seal, which could make it difficult to know if/when a seal has broken and the food is going bad. When you leave the rings off, you will know with a glance that a lid has popped off.
Mold can also grow on the underside of the rings, or the rings can rust and get stuck on your jar. Although this won’t necessarily ruin your food, it’s rather unsightly and you’ll likely have to throw the band away.
After learning this, I now store my bands in a little milk crate in my storage room with my other canning supplies. Yes, it takes up more space, but if something goes amiss with my seals, I’ll know right away!
Placing Filled Jars in the Oven to Keep them Warm Before Processing
This practice can be dangerous. Canning jars are not manufactured to withstand the dry heat of an oven, so they could explode and send glass shards and food everywhere. Generally, recipes are in small enough batches for the purpose of being able to fill and process all jars before they cool. If I have more food than I can process in one batch that needs to be kept hot, I’ll just keep it hot in the pot I cooked it in!
Some people might place empty jars in the oven to warm them before packing, but placing filled jars in the oven seems like a risk best not taken.
Failing to Adjust for Altitude
Most processing times and weight (for pressure canners) are for altitudes below 1,000 ft above sea level. Anything above, and you will likely have to increase your processing times or psi. Even in recipe books it’s given as one processing time, and if you failed to read the information at the front of the book, you may miss that critical bit of information.
For example, I live at 1,203 ft above sea level. That means that I have to add 5 minutes to my processing times. A recipe that calls for 10 minutes of processing time gets increased to 15 minutes. For pressure canning recipes, I need to increase my psi. For example, all the pressure canning recipes in the Ball Blue Book are for 1,000 ft or below and call for 10 psi, so I need pressure can at 11 psi.
In most recipe books you will find an Altitude Chart in their “Canning Basics” section, and on USDA online recipes they are usually found at the bottom of the page. In all my recipe books I highlighted my altitude requirements so I can quickly reference them.
Failing to Vent Steam before Pressure Canning
Air trapped in your pressure canner after you close the lid can cause the temperature to be lower than is necessary for the pressure you are trying to reach. This can cause under-processing and leave behind the Botulism bacteria.
Venting steam for ten minutes before closing the vent pipe and pressurizing the canner forces the air out of the canner so your canner can reach the proper temperature to make your food safe. In some recipes, this step is omitted completely, either because it assumes you know how to operate the canner (some USDA recipes) or the author doesn’t know any better (many bloggers).
Although the above mistakes aren’t necessarily going to ruin your food, it can save you time and a few broken seals. Remember, no matter what bloggers or YouTube canners tell you they do, make sure to follow manufacturer directions.
A Final Word
With all the scientific research readily available, it’s a wonder that disreputable, unsafe methods and recipes are still in circulation. Unfortunately, nobody but yourself can stop you from taking the unsafe advice of canners who have been running against USDA recommendations for years and “haven’t gotten sick yet”. Botulism is rare, luckily, but do you want to take that risk for you and your family and friends now that you know how devastating it can be?
Even if you are lucky enough to avoid Botulism from poorly processed home canned food, you are still at risk of food poisoning. Ever had the “24 hour stomach flu” after consuming a friend or relative’s dishwasher canned strawberry jam? Gut rot after solar canned dill pickles? That’s not the flu, that’s food poisoning.
If you’re a new canner just starting out, or maybe an experienced canner looking to update your knowledge, I hope this article has helped you identify bad recipes and discover reputable sources to reference on your home food preservation adventure.
Make sure to scroll down for more resources I have used that can explain Botulism, safe canning practices, and other important scientifically proven facts!
Happy and SAFE canning!
Water Bath Canning
Unsafe Canning Practices
Unsafe Home Canning Practices – Healthy Canning
Downright Unsafe Canning Methods – Michigan State University Extension
Canning FAQs – National Center for Home Food Preservation
How Did we Can? The Evolution of Home Canning Practices – United States Department of Agriculture
Canners and Canning Methods that are Not Recommended – Pennsylvania State University Extension