Pressure canning and water bath canning have recently become much more popular due to the increase in home food growers, so it follows that there's also a big increase in newbies or first-time canners.
There are many critical areas of canning to learn before beginning, and one of the most important things to learn about canning is the ingredients that you should NOT can. It may surprise the new canner to learn that there are foods that simply cannot be canned safely.
You may find differing opinions (and even arguments) about the items on this list. There are people who will say, "Well, I've done that and never gotten sick." There are people who choose to can food outside the recommendations of the National Center for Food Preservation which is, in my opinion, the best go-to source for correct canning procedures and recommendations.
Good canning books are a great start and you can never have too many. There are many great ones available these days and some of my favorites are interspersed throughout this article.
The following list was developed with the National Center for Food Preservation guidelines in mind. Creative canners are free to disagree.
So here's my list of Ten items (or categories) that shouldn't be canned, and a brief explanation as to why they are not recommended.
There is currently not an approved canning method for canning eggs that is shelf-stable. This is because the density or thickness of the skin of the egg makes it difficult for the heat to penetrate every level of the food the way it needs to order to kill off bacteria and mold spores.
This includes pickled eggs. Although you may find many recipes for canning pickled eggs, a
The category of thickeners include ingredients such as cornstarch, cornmeal, and flour.
Thickeners make it difficult for the heat during the canning process to penetrate through every layer. In addition to that, these ingredients will breakdown under the extreme heat of processing and they will settle as mush at the bottom of the jar.
Specifically, items that contain cornstarch shouldn’t be canned because of their ability to break down acidic food mixtures and interfere with heat-killing pathogens.
When you later open the can of your preserved foods, you can always add the thickeners at that time.
Pasta and Noodles
Pasta or noodles are made of flour. They will breakdown in the jar during the 75 minutes to process in the pressure canner and you will, again, be left with mush at the bottom of the jar.
Also, most pasta and noodles are made with eggs, which, as stated above, is also an ingredient that shouldn't be canned.
This category includes milk, cheese, sour cream, whipping cream, yogurt, butter, cream, buttermilk, tufa, soy or coconut milk, etc.
The amount of heat required for dairy items to be canned correctly would actually make the foods inedible.
Milk and cheese, especially, can potentially be contaminated with Clostridium (C.) botulinum, the botulism-causing bacteria. The pH of cheese qualifies it as a low acid (pH 5.1 to 5.9) food and thus is in the canning danger range as botulinum could grow and make canned hard cheeses unsafe.
Dairy products are also of thicker consistency which leads to concerns of bacteria forming in the jar and not being thoroughly sterilized during the preserving process because of the heat’s inability to get through each layer.
This category includes oats, rice, barley, wheat, cornmeal and bread. There are several reasons why grains shouldn't be canned.
The first issue with canning grains is when you heat them, you destroy the nutrients inside them and also drastically shorten their lifespan. They’ll turn rancid faster and last for a lesser amount of time.
In addition, grains don't contain heat well so the inner part of the grains won’t get hot enough to kill bacteria. This is dangerous because bacteria and mold spores can hide in the deeper layers of the food and cause you to get sick when ingested.
Although grains can be cooked inside of canning jars in your pressure canner, that doesn't mean that they're shelf-stable or even sterilized for that matter.
Purees like pumpkin puree or squash puree are too gelatinous to can at home. Cooking cubed pumpkin, however, is a nice alternative that is safe to eat. Cubed squash will compress during heating and become too thick.
It’s a better idea to freeze whatever vegetable you’re making purees from for later use. You could also can the vegetables in larger chunks by canning. This should help the veggies keep their shape during the process.
This category includes lard, oil, mayo and butter,
with the exception of a small amount that may be included in a recipe.
Foods that contain a significant amount of fat tend to turn rancid faster than other shelf-stable foods.
Also, again, the thickness can make it difficult for the heat to penetrate every layer during the canning process which can leave room for bacteria to form in the food, which could lead to botulism and mold contamination.
You cannot can dry beans that have not been soaked previously or were partially cooked. Said another way, you cannot put dry beans in a jar for canning.
Refried beans make the list because the thickness of them is too much for the heat to penetrate the interior of the jar.
Most nuts have an oily texture and can lead to botulism. Their oily texture coats and insulates botulism spores and creates an anaerobic micro-environment which allows the spores to live in a high-heat environment.
So there's my list. Soon after starting your canning adventure, you will gain some experience and knowledge about the intricacies of canning and begin to feel that it's really not as scary as it first seems.
Canning is a great way to preserve food for your family, but it always needs to be done safely.
Ready to begin? To read our article on the items you will need to get started, click here.