Canning is a method of food preservation which, when done correctly, can prolong your food’s shelf life indefinitely. That said, dry canning isn’t quite the same.
I’ve talked a little bit about dry canning before, but I wanted to know more about it and answer a question that I see often online: is dry canning safe?
No, dry canning isn’t safe. and is not recommended in any canning book or by canning experts.
Unfortunately, the jars can’t handle the intense heat which may cause microfractures, leading to the jar breaking. The heat also releases the natural moisture of the jar’s contents which bring a risk of mold.
Let’s take a closer look at dry canning, why it’s unsafe, and some methods you can use instead…
What is Dry Canning?
Dry canning is a method of food preservation wherein you place dried foods (i.e. beans, grains, nuts, etc.) into canning jars. The jars are sealed, placed in an oven, and heated to 200 degrees Fahrenheit (93 Celsius) or more.
Canning and Dry Canning Are NOT the Same!
Okay so, what’s the difference between canning and dry canning?
Canning is a process by which sealed containers of moist foods are heat treated at a high temperature for a certain length of time; the idea being that after the jars have been heat treated, you can safely store their contents for long periods of time.
Dry canning (also called oven canning) involves placing dried foods like grains, nuts, and beans into sealed canning jars and heating them in the oven at 200 degrees Fahrenheit (93 C) or higher.
Some people argue that dry canning is different from oven canning and evolved from this process. In oven canning, the food is placed inside a sealed canning jar on a cookie sheet, then placed in the oven and “baked” until “done.”
Some versions of dry canning call for the pre sealed jars, others do not.
Note: some dry canning instructions say to seal the jars after they’ve come out of the oven.
Ultimately, neither option is safe.
According to multiple high authority resources, including Utah State University Extension, the National Center for Home Food Preservation, and more, dry canning is simply just not an effective or safe canning method for long term food preservation.
Why Is Dry Canning Unsafe?
Here are some of the biggest issues with canned food produced via this controversial canning method…
Mason Jars Will Break
Let’s start off easy, the jars are heated to 200 degrees Fahrenheit. Oftentimes they’re not designed to handle that kind of heat, and may end up breaking either while in the oven, or on the way out.
Moisture Build Up and Mold Growth
There’s a serious risk of mold. The heat from the oven releases the moisture held by the jar’s contents. If the jar’s open, the moisture can evaporate and move off but if your jars are sealed there’s nowhere for the moisture to go.
This means that moisture often forms pockets inside your jar. The jars also cool down when removed from the oven which results in condensation on the inside of your jar. These moisture pockets and condensation can cause mold to form.
The moisture pockets also become a sort of breeding ground for bacterial spores like Clostridium Botulinum (which forms botulinum toxin) and pathogens like salmonella which are resistant to drying.
To say that these things are nasty is an understatement. Salmonella infections are common and typically cause stomach cramps, fever, diarrhea, and a generally upset stomach.
With that said, salmonella poisoning is rarely fatal, and most people don’t need to seek medical attention for it as the infection typically clears up on its own in a few days.
Botulism – the illness caused by exposure to clostridium botulinum – is the exact opposite. It’s rare but when it does occur it can be fatal (especially if left untreated). Symptoms include weakness, blurred vision, fatigue, nausea, diarrhea, and difficulty breathing.
Even “Dry” Foods Aren’t Really Dry
Many proponents of dry canning argue that dry canning is a perfectly reasonable method of food preservation because there isn’t that much moisture in the foods they are canning.
For instance, some “dry foods” like white flour, white rice, pasta, cereal, whole grains, cornmeal, oatmeal, barley, and even hard cheese don’t have that much water in them.
However, these dry goods aren’t as dry as you might think. Some can contain as much as 30% moisture! Putting these foods in any kind of heat, as we mentioned, causes the moisture to migrate and create pockets that lead to the growth of bacteria.
Dry canning also lends itself to food products that are, in terms of long-term food storage, not that great to eat.
Especially in the case of products like nuts and grains, you’ll notice increased oxidation when you heat them via dry canning, causing them to go rancid shortly after.
Finally, one last problem with dry canning is that there is a poor circulation of heat inside the jars.
This can result in uneven cooking, with some areas of the food being undercooked and others being overcooked. Additionally, it can lead to food spoilage, as the lack of circulation can allow bacteria to grow.
There are a few other safe alternatives for storing foods like flour, beans, and nuts.
First, keep in mind that these dry goods tend to have a fairly long shelf life on their own, particularly when properly stored.
The best method for long-term storage of these items is generally to place them in food-grade buckets (plastic buckets with lids) and this should help keep them of high quality and also provide some level of insect control. Store the buckets in a cool, dry place out of light.
You can also use a vacuum sealer machine that is specifically designed for jars. Foodsaver is one manufacturer that offers this. The machine works by sucking the moisture from the rim of the jar and helps to eliminate any air that might cause the food to spoil.
Oxygen absorbers also work quite well. These are placed inside the jars of food and can preserve their quality and offer some level of insect control.
To use these oxygen absorbers, all you need to do is put the dry food in a canning jar or Mylar bag. Put the oxygen absorbers on top, seal the jar with the lid and ring.
In just 30 minutes, the packets will absorb the moisture and allow the jar to seal. They can be used with food-grade buckets as well.
The only downside to this method is that every time you open the jars, you’ll be exposing the contents to oxygen. However, this would be the same level of exposure as if you dry canned the food anyway, so you may want to consider it.
Okay, so to recap:
- No, dry canning isn’t safe.
- The jars often can’t handle the temperatures used in the heat treatment and will break either inside the oven or on the way out.
- The sealed jars trap moisture produced by the heat of the oven which creates pockets in the food and gives us a potential risk of mold as well as the formation of bacteria like Clostridium Botulinum and pathogens like Salmonella.
- Dry canning also reduces the shelf-life of the jar’s contents.
The answer to this question is clear-cut: don’t do it unless you want to waste a lot of food and potentially make yourself and your family extremely sick.
Considering the risks involved with dry canning and the potential negative effects it has; I’m surprised people would try it at all – especially with all the articles online advising against it.
We should always be careful about how we preserve our food; especially with the current pandemic still doing the rounds. That said, I hope you guys enjoyed this article and found it to be informative.
No. Dry canning is not a USDA-approved method of preserving food for long-term storage.
While dry canning is often touted as a space-saving method, it is important to note that it is not recommended by food safety experts. Without any liquid, there is nothing to prevent the growth of harmful bacteria. In addition, the lack of moisture can cause the food to spoil more quickly.
When ground beef is dry canned, it creates an oxygen-free environment in which botulism can flourish. Instead, use a pressure canner to safely process your ground beef.
Greg spent most of his childhood in camping grounds and on hiking trails. While he lives in the suburbs nowadays, Greg was raised on a small farm with chickens. He’s a decent shot with a bow, and a huge knife enthusiast. Find out more about Greg.