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. In fact, it shortens the food’s shelf life. Unfortunately, the jars can’t handle the intense heat which may cause micro-fractures, leading to the jar breaking. The heat also releases the natural moisture of the jar’s contents which bring a risk of mold.
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 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.
Note: some dry canning instructions say to seal the jars after they’ve come out of the oven.
Problems with Dry Canning: Why is it Unsafe?
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.
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.
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.
Thanks for reading and I’ll see you for the next one, take care and stay safe!
Greg spent most of his childhood in camping grounds and on hiking trails. While he lives in suburbs nowadays, Greg was raised on a small farm with chickens. He’s a decent shot with a bow, and a knife enthusiast.