One of the great things about canning is that there is hardly anything that can’t be canned. You want to preserve fresh fruits and veggies? No problem. Maybe some pickled ones? Absolutely. You want to can meat? Sure thing.
It’s easy to go a little crazy with this power of preservation, but despite appearances not quite everything can be canned safely.
How about soup? You can buy it canned and preserved right off the shelf in the grocery store, so it stands to reason we can can it at home. But is it safe to can it?
Yes, it’s safe to can soup but only certain kinds with certain ingredients. Dairy products, starches, thickeners, and certain vegetables greatly increase the risk of canning failure and attendant bacterial contamination.
This is a good news-bad news sort of situation. Broadly, yes, you can safely pressure can soup at home. However, the water bath canning method is a bad idea and not recommended.
But it’s really easy to get the process wrong or add a seemingly innocent ingredient and compromise it, meaning the soup will be at extreme risk of spoilage or hosting the bacterial spores that can lead to botulism.
More than most things, you’ve got to stick to a recipe in a strict process when canning soup. I’ll tell you more below.
The Safety of Canned Soup Depends on the Ingredients!
Understand this right up front: the safety of your canned soup is almost entirely dependent upon the ingredients. The bottom line is that some common soup ingredients will imperil the safety of the operation.
We’ll talk more about these in detail below, but what this means is that most recipes, as they are commonly prepared, will have at least one thing in them that prevents them from being pressure canned with certainty.
Accordingly, don’t plan on making a big batch of soup and then canning most of it. If you want to go that route, you’ll need to modify the recipe or make a sort of soup base that can be canned. Then it can be completed later when you pull it out of storage. A few kinds of soup that are safe to can (so long as you follow the guidelines) include:
- Chicken Stock
- Turkey Stock
- Beef Stock
- Vegetable Soup
And here’s a quick overview of what not to do or do when canning soup, before we go into more detail:
- ✘ Don’t can cream soups
- ✘ Don’t add thickening agents (flour, cornmeal, cornstarch)
- ✘ Don’t add cauliflower, broccoli, pumpkin, and other squashes
- ✘ Don’t add sour cream, milk, cream cheese
Improperly Canned Soup or Trying to Can the Wrong Soup Can Cause Botulism!
So what’s at stake if you mess this up? I’ll tell you straight, it’s really bad: botulism.
Botulism is an illness caused by a neurotoxin, one produced by a type of bacteria, Clostridium botulinum, an infamous and potentially deadly germ that’s known to inhabit canned food that is improperly prepared, or food that cannot be canned properly in the first place.
Botulism is seriously bad news, being caused as it is by a neurotoxin. Symptoms include total or partial paralysis of the muscles that control the eyes, jaw, and throat along with a host of other disruptions in the autonomic nervous system.
It can even paralyze the intestines, causing dangerously severe constipation, and low blood pressure that puts victims in a lightheaded and potentially fainting state.
Certain strains of the toxin also cause intense nausea, vomiting, and respiratory problems owing to paralysis of the muscles responsible for the diaphragm and lungs.
Trust me, it’s horrendous and can be fatal. Don’t want it? Don’t take any chances when canning soup.
“Cream” Soups Especially Cannot Be Canned Safely
One blanket prohibition when canning soup is the canning of cream-style soups. Any soup that is made with any dairy products or that has a thick, opaque consistency for any reason must be avoided.
That’s because these soups invariably have major problems when it comes to getting enough heat to the center of the jar, and that means there’s always going to be a chance the bacterial spores that produce the neurotoxin causing botulism might persist.
So, in total, no creamed soups whatsoever, of any kind!
Adding Thickeners Can Make Soup Unsuitable for Canning
Likewise, in the same way that creamed soups cause problems, thickening agents added to any other kind of soup are also prohibited entirely.
Whether it is flour, cornmeal, cornstarch, or anything else, you can’t add it to the soup broth or base you plan on canning. Doing so will simply increase the chances of failure by preventing the thorough heating which neutralizes those bacterial spores.
Note that there are a few rare exceptions: when you’re looking up safe recipes that call for a gelatin additive, ones that have been scientifically tested mind you, you can rely on them as long as they aren’t altered in any way! Stick to the script or don’t even attempt it.
Noodles and Dumplings are Another No-Go for Canned Soup
Storage is problematic when pressure canning soup at home. This means that common soup ingredients like noodles of any kind, any other kind of pasta, and any grain like rice, oats, barley, and so forth must not be added to soup going into the pressure canner.
Once again, it is impossible to heat them thoroughly enough, consistently enough, to fully eliminate the risk of bacterial contamination and subsequent botulism or other food poisoning. Don’t risk it.
The good news is that these ingredients can be safely added when you prepare the soup later. More on that in the following sections.
Some Veggies are Just Problematic
Regrettably, some common and seemingly safe vegetables serving as ingredients in popular soups are inherently problematic for our purposes.
Notable offenders in this category include cauliflower, broccoli, pumpkin, and other kinds of squash. These ingredients, no matter how small they are diced, tend to get smashed together and subsequently interfere with thorough heating during processing.
Believe me, I know the temptation is there to experiment considering the popularity of these veggies, but remind yourself that you’re gambling with your life if you try.
Avoid Adding Dairy Prior to Canning
As mentioned briefly up above, dairy ingredients are to be avoided when canning soup, but to be perfectly clear they must not be added at all. They don’t have to result in a creamed or thickened soup in order to cause safety issues!
Never add sour cream, milk, cream cheese, or anything else to your soup even if it is a required ingredient.
Again, it is possible to add these ingredients when pulling the soup base out of storage and preparing it for consumption. You’ll just need to alter your recipe slightly and then the subsequent preparation.
Large Quantities Cannot be Canned Safely
Never use any jar that is a half-gallon capacity or larger for canning soup at home. Again, this makes it very difficult to thoroughly heat the contents and ensure safety. Likewise, smaller jars provide more assurance of safety.
DO NOT Improvise Canned Soup Recipes!
A final warning: do not, ever, try to improvise soup recipes for canning at home! You should only ever can soup recipes that have been scientifically tested for safety and repeatability using conventional pressure canners.
You can find these recipes, vetted ones, at many university extensions. Penn State has several good ones.
What to Know When Canning Soup at Home
It isn’t all bad news when canning soup at home. You’ve still got a surprising amount of flexibility and with just some slight modifications to your recipes and later preparation, you can enjoy pre-made soup all year long.
Adding Meat is Okay When Done Properly
To clarify a common misconception, yes, you can add meat to soup as long as you follow all of the rules above. Beef and chicken are perennially popular, of course, and are suitable for use in canned vegetable soup.
Canning Soup Properly Takes Time
Be prepared to spend some time putting your canned soup through the process. It will take at least an hour, and many soups can take upwards of 90 minutes in the canner, especially if you are using a larger jar. Speaking of larger jars…
Leave Plenty of Room in the Jar
As always, you want to leave headspace in the jar but it is especially important for soup. Packing of solid ingredients is also a particular problem.
As a rule of thumb, don’t fill the jar up more than halfway with your solid ingredients. Then add the broth afterwards, leaving 1 inch of headspace. This will ensure that the entirety of the contents can be appropriately heated.
Add “Problem” Ingredients Separately Prior to Serving
Remember all of those ingredients we talked about above that you shouldn’t add to your soup? Dairy, starches, noodles, thickeners and so forth? The good news is that you can add them prior to preparation or immediately after heating your canned soup when you pull it out of storage.
It might take a little bit of experimentation or trial and error to finalize your preparation while keeping that flavor profile you love, but it’s totally doable.
Remember all of these guidelines, and you’ll have no issues canning soup safely at home!
Tom has built and remodeled homes, generated his own electricity, grown his own food and more, all in quest of remaining as independent of society as possible. Now he shares his experiences and hard-earned lessons with readers around the country.
Find out more about the team here.