Ah, yes..."oven canning"...Hate is such a strong word that I don't care to use much, but when it comes to the "oven canning" method that some choose to use to preserve their dry foods long-term, it definitely conjures up a strong opinion in me. But I'll tone it down today and use the word "loathe" instead, because I truly do loathe the whole notion of oven canning.
Oven canning is the process of canning dry goods such as flour, beans, oats, and even nuts in a 200 degree oven. The standard instructions are to place items in glass canning jars, wet the rim of the lid a bit, place lid and ring on top, and then allow jars to remain in the oven for about an hour. The premise is that this is a way you can extend the life of dry goods even in a scenario in which you have no electricity (because you can “oven can” in a solar oven, or frankly, even in a car on a bright sunny day). However, I have a REAL problem with this method, specifically for canning dry goods—for which the practice is commonly used. I’d ONLY use this method if I had exhausted all other alternative options and I assure you, the loss of mainstream electricity would not be the prime motivating factor for using this method. Now, I realize that there are a lot of folks who tout oven canning for dry goods, but I’m going to share with you today the key reasons why I think it’s a really bad idea.
For starters, the key enemies of successful long-term food preservation are heat, light, air, and creepy crawlies. So why in the world would you START the life of your food that you intend to have on a long-term basis with deliberate heat?? I was astounded to find that some people use this method to preserve nuts! Nuts? Those are expensive even when you get the best kind of sales, and they are so vulnerable to going rancid over time even in cooler storage conditions. An hour in the oven at 200 degrees has “FAUX PAS” written all over it! You’ve just reduced the standard shelf life of your expensive pecans to approximately 50% with such a choice. Sealing them in a vacuum seal bag and freezing them or vacuum sealing them in a Mason jar is a perfectly suited solution for nuts and ALL dry goods. And if you sprinkle a bit of food-grade diatomaceous earth in each of your containers you can prevent the proliferation of creepy crawlies too. (Don’t worry. It’s actually GOOD for you so there’s no problem mixing it in with your dry goods, and a little goes a long way. I use about 2 heaping tablespoons in each of my 5 gallon buckets of whole grains.
Brown rice is so challenging to store long term because of its Omega fats it contains. Exposing those fats to heat like this will actually cause the grains to go rancid by as much as 50 times faster than merely storing it in your cupboard in its original packaging!
Let’s also keep in mind that an hour to an hour and a half of heat exposure comes with a heavy price when it depletes valuable nutrients! The oven canning method has the ability to convert what would otherwise be a valuable nutrient source into an empty calorie source when exposing some foods to this kind of process. I don’t have space in my inventory for many empty calorie resources.
Next, the suggested time frame of 200 degrees for an hour is intended to heat up the ingredients inside the jar, as well as the jar, in order to kill any germs and to cause a seal of the lid to the rim. Well, that formula will vary greatly depending on the density of what you’re sealing. I’ve never yet seen an enthusiastic blog/story about oven canning that takes that into consideration. Some advocates of the oven canning method suggest that you can even use previously used canning lids for this method. That would only be the case if the lid isn’t bent in any way, AND there is sufficient rubber left on the lid to melt and form a seal on the rim of the jar. That’s a whole lot of guessing that I suspect most of us aren’t really equipped to accurately configure. (Algebra, Geometry, or Physics anyone?)
Even if we didn’t have the obvious problem of exposing perfectly good foods to heat in the first place, we still have the oxygen problem. The oven canning process does not actually EXPEL all of the oxygen from the jar like you would accomplish with vacuum sealing or pressure canning. Instead, you’re storing your dry goods amidst the oxygen that remains in the jars. Heating the contents plus the lids doesn’t solve the oxygen problem, whereas pressure canning or vacuum sealing does. The seal may be airtight when you’re finished with this method, but the oxygen is still inside.
When I pressure can, I specifically dry the rims of each jar before putting the lids on them. This method commonly encourages the wetting of the rim. I see that as just asking for trouble. Again, moisture is one of the enemies of long-term shelf stability.
There is no need to oven can items such as rice, whole grains, and beans! Why spend all of that time oven canning something that will keep perfectly fine in a properly sealed food-grade bucket or mylar bags? Plus, all of those jars?? I have a LOT of full canning jars, yes, but I’m not going to unnecessarily add to that number if I don’t have to. I’d much rather grab a 5 gallon bucket of whole grain in a hurry than 10 ½ gallon Mason jars, wouldn’t you? And what’s more likely to break—Mason Jars or my buckets? What’s more likely to rust—full canning jars or buckets? Which is more likely to survive an earthquake or flooding? Yep. I think you get the picture. All you need with these kinds of dry goods is a good food-grade diatomaceous earth, a good seal on your lid (which you can get with gasketed lids or the gamma lids) and store the items in the standard conditions of cool (68 degrees Fahrenheit or cooler is ideal), dry, and dark environment.
Let’s not forget the price of oven canning these dry ingredients vs preserving them in #10 cans, FoodSaver bags, mylar bags, or food-grade buckets. Believe me, even when I get the jars at a yard sale or thrift store, the other options are still more friendly to my pocket book.
Granted, I am the most lazy prepper you’ll ever meet, so perhaps it’s the lazy woman in me that feels like I wouldn’t want to waste the time to do all that oven canning, but when there’s so many other, more viable options for properly preserving dry goods, why would you use the oven canning method? Using that much electricity and time to preserve the thousands of pounds of dry goods that I need to take care of my family for a whole year isn’t exactly attractive to me. The other methods are viable with or without electricity! For example, with the vacuum sealed method that I do with the FoodSaver, you can still get the same results by reversing the flow of a tire pump to extract the oxygen from a jar; there are still such things as Oxygen Absorbers; and there’s still the pressure canning method that is just fine over a fire or a wood cook stove.
Bottom line, I’m looking to protect my HUGE investment of my dry goods in the most practical, efficient manner with the least amount of risk to losing the food or compromising the nutritional value of the food. Oven canning simply does NOT meet that criterion.
There’s nothing worse than going through all of the trouble and expense of being prepared only to find, that the fruits of your labor are useless because you relied on imperfect methods. That moment of realization will turn a peaceful mood into a panicked, sick-to-the-stomach mood instead. So let’s pass on the oven canning, friends, and ensure Peaceful Preparedness instead.
You might enjoy this short YouTube video demonstrating why I love the vacuum sealing method so much: http://www.youtube.com/watch?v=3YaIBAjosYw&list=UUAaj2kthyvHCMgkm6PD_gcA...
To learn more about converting a tire pump into a vacuum, you might enjoy this video: http://youtu.be/wfVAwF5HGW0