The primary concern of all canners should be safety. While many foods can safely be canned, there are some that cannot.
But, all canned foods must be processed by the correct method in order to be safe for long-term storage. Those are the things that we will talk about in this article.
I have been canning foods for over 50 years and will tell you everything I know.
6 Foods That Can Safely Be Canned
Here is a list of the foods that can safely be canned and the method that must be used in order for them to remain good during long-term storage.
1. Fermented Foods
Foods like sauerkraut that have been fermented can safely be canned by using the boiling water bath method.
Most fruits are considered high-acid foods and have a pH of anywhere from 3.0 to 4.6. This means that because of their high acidity levels, most of the naturally occurring bacteria in the fruits can be destroyed by subjecting them to temperatures of up to 210℉, which is the temperature at which water boils.
So using the boiling water bath canning method is the best way of canning fruits. Here is a video demonstration on canning apples.
Fruits can also be pressure canned, but most types of fruit have such a delicate texture that the higher heat and the longer processing times at which the fruit would be subjected to those temperatures would damage the fruit and make it much less appetizing and flavorful than when canned in the boiling water bath.
Here is a list of many different kinds of fruit and how they rank on the pH and pectin scales:
- Fruits High in Pectin: Sour Apples, Blackberries, Sour Cherries, Crabapples, Cranberries, certain Grapes, Kumquats, Lemons, Loquats, Mayhaws, Melons, certain Oranges, Passion Fruit (skin), certain Plums, Pomegranates, Quinces.
- Fruits Low in Pectin: Blueberries, Figs, Grapefruit, Guavas, Papaya, Passion Fruit, Peaches, Pineapple, Rhubarb, Strawberries.
- Fruits High in Acid: Crabapples, Currants, certain Grapes, Loquats, Raspberries.
- Fruits Low in Acid: Sweet Apples, Blueberries, Sweet Cherries, Figs, Melons, Papaya, Passion Fruit, Peaches, and Pears.
3. Jam and Jelly
Jam and jelly, which are made with fruits that are high in acid content, can be safely made and canned for long-term storage by using the boiling water bath method.
The pH of fresh meat of all kinds ranges from 5.5 to 6.2, while fresh poultry ranges from 5.3 to 6.5, and fish and shellfish fall on the pH scale of around 7.0. But they all have one thing in common. They are considerably lower on the pH scale than the 4.6 point, which is the dividing line between low and high-pH foods.
So in order to be safely preserved for long-term storage, all types of meat must be pressure canned, and most must be processed for 75 minutes for pints and 90 minutes for quarts, per the National Center For Home Food Preparation.
To demonstrate the process of canning meat, here is my video on canning beef stew:
Although pickles are normally made with cucumbers, beets, and other vegetables that are low-acid foods, vinegar is used in pickling, which works with the canning process to destroy bacteria and render the food safe for long-term storage.
That combination of vinegar and the canning process allows pickles to be safely canned by using the boiling water bath method.
Here are a couple of videos to give you an idea of how the pickling process works:
If you are wondering what the differences are between pickling and canning, you can find the answers to all your questions in my article Pickling vs. Canning | What’s the Difference?
The pH of vegetables ranges from 4.65 to 7.5, so they all must be pressure canned. However, there are some vegetables that should not be canned because they are so delicate that the heat needed for the pressure canning process will overcook the vegetables and make them inedible.
Vegetables like cauliflower and broccoli that cook very quickly and are not good when overcooked should not be canned because both canning methods involve subjecting the food to high heat for extended periods of time that would cook those delicate vegetables to mush.
To demonstrate the pressure canning process, here is my video on canning mustard greens:
There are 3 exceptions to these rules, however. Figs, papaya, and tomatoes which are on the low end of the pH scale, can be water bath canned by adding some form of acid to the food.
- Figs – Figs range from 4.92 to 5.0 but can safely be boiling water bath canned by adding either 2 tablespoons of lemon juice per quart or 1 tablespoon per pint or 1/2 teaspoon of citric acid per quart or ¼ teaspoon per pint.
- Papaya – Papaya ranges from 5.2 to 6.0 on the pH scale, which is definitely on the low side of the scale, but they can be water-bath canned by adding lemon juice. Make a syrup to can the papaya in, and for every quart of syrup, add ¼ cup of lemon juice.
- Tomatoes – Tomatoes range between 4.3 and 4.9 on the pH scale, depending on the variety, but can safely be boiling water bath canned by adding 1 tablespoon of lemon juice per pint or 2 tablespoons of lemon juice per quart.
4 Foods That Cannot Safely Be Canned
1. Chocolate Sauces
According to the National Center For Home Food Preservation, although there are many recipes available on social media for canning chocolate sauces, sauces are a low-acid food and cannot safely be canned by using the boiling water bath method. In addition, there are not any “science-based, tested” chocolate sauce recipes that have been developed by any of the Cooperative Extension Service partners, and as a result, they recommend that chocolate sauces be frozen and not canned.
If you are like me, this is not the news you wanted to hear. But they do, however, post a good freezer chocolate fudge sauce recipe on that page for us to use.
Many of us often wonder why it is not recommended that we can milk, butter, and other dairy products and that we shouldn’t even add dairy to soups and other foods that we do can. But, according to Dr. Elizabeth L. Andress, who is the National Director of Home Food Preservation, it is simply a matter of “chemistry and microbiology.”
In short, fats can protect botulism spores during the canning process, so the amount of heat that would have to be applied to kill the bacteria would be detrimental to the quality of the milk.
Like some of the other foods that are considered unsafe for canning, dairy should be frozen for long-term storage, not canned.
3. Hot Dogs
Here is another instance of seeing many recipes and videos on social media about canners offering their personal information on how to can hot dogs.
But, when I did some research on this topic, which is detailed in my article Home Canning Hot Dogs: Should It Be Done? I discovered that home canning hot dogs should not be done because there is no research-based information or procedures available that have been established by canning professionals.
Canning fresh sausages, yes, but canning hot dogs that are loaded with lots of preservatives, there just isn’t any proof that it is safe to do.
4. Peanut Butter, Pumpkin Pulp, & Sweet Potato Pulp
I’m lumping the information for all three of these food items together because the reason that all three shouldn’t be home-canned is the same.
Peanut butter, pumpkin pulp, and sweet potato pulp are all so dense that there has not been a process developed that has been proven to destroy all the bacteria throughout the food.
In order for that to happen, the temperature in the entire canning jar, which includes all liquid and all food, must reach a certain temperature and remain at that temperature for a certain period of time in order to kill the bacteria. But, so far, there is not a test that can definitively determine that that has happened in food as dense as peanut butter or pumpkin and sweet potato pulp.
The best way to safely can these three items are as follows:
- Peanut Butter – You can freeze whole peanuts so that you can make a batch of peanut butter when you need it, and you can freeze homemade and commercially produced peanut butter.
- Pumpkin Pulp & Sweet Potato Pulp – To can pumpkin and sweet potato, can them in chunks which can safely be pressure canned, and then mash them when you are ready to use them.
Why Foods Are Canned By Different Methods
The necessity of having two different canning methods is actually quite simple and has to do with the pH level of foods.
Low-acid foods have a pH level of 4.6 or higher and must be pressure canned.
High-acid foods have a pH level of 4.6 or lower and can be either pressure canned or boiling water bath canned.
Read on for a more complete explanation:
- The purpose of canning is to render foods safe for long-term storage by killing the bacteria that is naturally occurring in all foods.
- The bacteria that we are concerned with destroying is the bacteria called Clostridium botulinum which causes food poisoning or botulism.
- When food has high levels of acid content, which are the high-acid foods that have a pH level of 4.6 or lower, the natural or added acid plus heat at the temperature of 210℉ kills the majority of the bacteria when cooked for a specified period of time. 210℉ is the temperature at which water boils, so the boiling water bath method is sufficient to can high-acid foods.
- When food has low levels of acid content, which are the low-acid foods that have a pH level of 4.6 or higher, there is not enough acid in these foods to help with the process of killing the bacteria, so higher temperatures between 240℉ and 250℉ for cooking at longer periods of time are required to kill the bacteria. Pressure canning is required to reach those temperatures of 240℉ to 250℉ and must be used to safely can low-acid foods.
For more information on the pH factor’s involvement in canning, see this publication by Clemson University, which is one of the USDA National Center For Home Food Preservation research sites.
How To Preserve Foods That Cannot Be Canned
Let’s take a minute to talk about the foods that cannot be canned and decide the best course of action to preserve those foods without being able to use the canning process.
Here is the list of foods we mentioned earlier in the article:
Although broccoli will not hold up under high heat for the length of time required for canning, it is perfect for freezing. If it is blanched properly before it is frozen, it will taste very close to fresh when thawed and steamed for a very short time, usually 3 to 5 minutes.
It isn’t necessary to thaw the frozen broccoli before cooking.
This video shows how to blanch okra, but it’s the same process for broccoli:
Cauliflower, like broccoli, should be cooked no more than 3 to 5 minutes for maximum flavor and texture. If cooked longer, it will be mushy and tasteless.
The best way to preserve cauliflower for long-term use is to blanch and freeze it. Although cauliflower will be good in the freezer for up to a year, for maximum taste and texture, it should be used within 6 months.
Again like broccoli, it isn’t necessary to thaw frozen cauliflower before cooking it.
Chocolate Fudge Sauce
Chocolate fudge sauce is another food that can be stored for long-term use by freezing it. My recommendation is to freeze it in smaller batches, the size you would normally use, within a short time so that you are not taking the chance that the entire amount will not be used and some will spoil, and it is just too good to waste.
Thaw the sauce overnight in the refrigerator, although it can be thawed faster by setting the frozen container in a bowl of cool water for a couple of hours.
Here are some good containers to hold the fudge, found on Amazon.
Milk, buttermilk, butter, cheese, sour cream, yogurt, and cream cheese are also foods that can be frozen to keep for long-term use. Although it is recommended that milk be stored in unopened original containers, gallon jugs should be opened and a small amount, at least ½ cup, removed from the container to allow for expansion and avoid the container either warping or splitting. Frozen milk will last in the freezer for up to 6 months.
All the other dairy products can be frozen in their original packaging but should also be put into a freezer bag or freezer-safe, airtight container before freezing to avoid freezer burn. They should also last up to 6 months.
Freezing will affect the texture of some dairy products, but the taste will not be changed.
The best way to store an extra supply of hot dogs is by freezing them. Just put the unopened package into a freezer bag to protect against freezer burn. Opened packages should be put into a freezer-safe container, like this type from Amazon, before freezing. Hot dogs will remain good in the freezer for at least 2 to 3 months.
Peanut butter is one of those foods that has a relatively long shelf life, even without canning or refrigeration. It can last unopened in your pantry for 6 to 9 months, and after it is opened, up to 3 months.
But, the shelf life can be extended by freezing it in its original container for 6 months, or it can be separated into smaller containers so that you are only taking out of the freezer the amount that you can use within a short time.
Pumpkin Pulp & Sweet Potato Pulp
I’m combining these two again because they can be treated the same. Even though pumpkin pulp and sweet potato pulp cannot be canned safely, they can both be canned in chunks and then mashed before use.
But both pumpkin and sweet potato in pulp form can be frozen for up to a year if properly packaged in an airtight container.
Thanks for stoppin’ by!
Hey there, dear reader! It's Jelly Grandma here. When I was a young'un, I remember the sweet scent of peaches and the warm, summer afternoons spent with Mama in the kitchen. Those days, we'd can...
There's an old saying among cooks: "The kitchen isn't a place for perfection but for fixing mishaps and making magic." And if there's one thing I've learned from more than half a century of cooking,...