Canning in an oil bath instead of a pressure cooker?
I've looked around but haven't found an answer to this one so maybe someone on here can help.
I do a fair bit of canning with fruits and what-not but wanted to get into more serious stuff like fish, etc. Due to space restrictions and my disinterest in adding another gizmo to sit in the back of my kitchen cupboards for most of the year, I would rather not get a pressure cooker.
If the idea is to get the internal temperature up to 240-250 which is impossible to do with an open pot of water, why not just substitute a cooking oil? It's cheap and I could reuse it for a dozen batches in the fall, then make french fries and be done with it.
Anyone lost an aunt to botulism with this crazy idea or could it possibly work?
Ah, what?? Are you thinking of processing jars of food products, like fish, in boiling oil, or at least 240°? Am I reading this correctly? You haven't found an answer to this because NO ONE DOES THIS. Canning under pressure and what amounts to deep fat frying jars packed with food are completely different animals, the latter being an unknown culinary technique. Pressure canning is not the same as the confit technique, jar or no. Perhaps if you have access to a pressurized deep fat fryers, like KFC uses, you could try that, but I doubt whether you own one of those. I'm not recommending this for canning, though.
The pressure canner is the only choice for canning food products not suitable for the water canner method. Also, please note that you would not use a pressure "cooker," as you wrote, but a pressure canner, for this; size and heat up/cool down times being the basic differences between the two pieces of equipment. A pressure canner should be able to hold at least 4 quart jars to be considered for canning use. Food processed in a pressure cooker will most likely be underprocessed, which can easily lead to spoilage.
Hopefully I've dissuaded you from using the oil bath method. Look into buying a pressure canner. Where do you live that oil, soybean or canola, is that cheap?
I suggest you do some further reading on the pressure canning subject, if you haven't to date, and seriously discard the oil bath canning idea. Not only will it not work, but it may prove to be quite dangerous on many levels. I doubt you'd even get a seal on your jars with the oil bath method, to say nothing of the oily mess, large quantity of hot oil on your stove or God forbid, in one of those turkey fryers, storing that oil after, etc. I can see a jar of something in liquid cracking in the oil and the ensuing explosion, yeah....
Btw, pressure canners will not break the bank, and are a commodity now, as the population is turning once again to canning and preserving food, since the economic downturn; they can be loaned to family members and can be leased out to neighbors for a nominal fee. You can make this valuable piece of canning equipment work for you in more than one way.
Here's a few links to get you started down a different path:
I'm going to run this by my sister, who is a pressure canning expert, and she what she has to say.
This sounds like a disaster waiting to happen!
Buy the pressure canner, and a good book on canning. Find a place to put them. Don't risk lethal food poisoning, boiling oil burns, and cuts and more burns due to the canning jar violently exploding spraying super heated steam, boiling oil and glass all over you and the kitchen.
Many pressure canners can also be used for hot water bath canning.
If you are short on space, my advice would be to find one of those, and swap that out with your water bath canner.
re: piano boy
"what a pressure canner does... increase the heat of its contents passed the boiling point of water?"
That's it's sole purpose. The pressure in the canner from the steam created by the smaller (as opposed to a water bath canner) amount of water forces out air, raising the interior pressure, therefore raising the temperature past 212° to a safe processing level. Since the canner is now filled with water vapor, the heat will be evenly conducted around the jars.
As al b. darned wrote below, your oil bath theory would probably work, although I'm not completely convined the jars would seal, not to mention how you decide on the correct processing times, but there are way too many things that could go wrong. I ran this idea past my pressure canning expect sister and her response was something along the lines of that's insane, what a mess to clean up, how dangerous, yadda yadda.
I hope the posters who have responded here have convinced you to do purchase a pressure canner.
I think no matter what the external temp is the food in the jar will not be heated higher than the boiling point of water unless you add pressure. Some people can with an oven but this is unsafe for that reason.
Actually, in theory this would work. The purpose of pressure canning is to raise the temperature of the food to at least 240 deg F. and keep it there long enough to kill any bad stuff in the jars. If you had a large enough kettle, enough oil to at least cover the jars by an inch, and a way to control the temperature it could work.
Would I do it? NOT ON A DARE!!! There are just too many ways for something to go wrong and set yourself on fire and/or burn your house up and down. This would surely ruin your day, not to mention the batch of canned goods. Even doing it outside in a turkey fryer is patently stupid.
Even if you could pull it off, there is so much clean up after everything cools down, IMO it wouldn't be worth the effort.
Due to space restrictions and my disinterest in adding another gizmo to sit in the back of my kitchen cupboards for most of the year,
What are you proposing to "process" the jars in?
You can buy a Presto canner (with a proper pressure gauge) at Amazon for about 70 bucks (w/free shipping), and it cal also be used as a boiling water canner, and to boil corn and lobsters in. An awful cheap insurance policy IMO.
I think the jars would blow up, since the contents would be at or over a boil, creating pressurized steam inside the jar that will be not be balanced by pressure outside the jar. Boom.
My husband and I were just talking about this earlier this evening, when we decided to see if anyone else had ever tried it, lol. I, too, have recently gotten in to canning, but am hesitant to buy another gadget to store. My geek-hubby came up with the idea of oil, too - and we were trying to figure out if it would work.
After giving it some thought, I think I wouldn't try it - mostly because I'm afraid that when submerging the jars, while the air is being expelled but before there is a good seal, some oil would get in between the rubber seal and the glass - causing an improper seal. Smarter heads than mine might be able to come up with a solution to that.
If you decide to try it though, I'd do it as a limited run, and store for a few months to see how the seal holds up before trying again. Also if you try it - please post and let us know if it works. :-)
Don't encourage the OP. This is just dangerous on many levels, and don't you try it either. Jars leak more often than one would think, and you will have some level of an boil over or explosion if liquid from the jars gets into the hot oil. Apart from the sealing issue, how can you tell, timing-wise, when the food is properly processed? That may lead to Russian roulette with underprocessed food products. Also, if you and yours survive the canning, consider cleaning up the mess of greasy hot jars of processed food.
I don't want to beleaguer the point here, and I've said all I'm going to on this subject, but please, be safe, and don't attempt this as a method of canning. If it was a viable canning option, the National Center for Food Preservation and other knowledgeable government agencies would recommend it. Call your local agricultural extension service and run it by them, if you're still considering it.
Check your inssurance policy before proceeding; if you get a faulty jar/seal, etc. leak as mentioned by Bushwickgirl, an explosive boilover could ignite the superheated oil when it hits the burner. This will cause an immediate flash fire burning anything and anyone nearby. DON'T TRY IT!!!!!!!
I'd hardly call 240 degrees super-heated oil - most deep frying takes place at much higher temperatures. If you were concerned about the jars exploding due to temperature changes, you could submerge in oil first and then bring up to temperature - the same as you would do when canning with European style canning jars.
I'm hearing a lot of hand wringing and haranguing about how it's just not done that way, but not anyone actually thinking about the science of it.
Pressure canner makes food safe because it heats it to 240 degrees which kills botulism.
Water bath canners cannot 212 degrees without pressure.
Ergo, canning in oil - which can reach and hold a steady temperature of 240 degrees, seems like a possibility.
Is it one I'm going to try? No - but not because I don't think it could work somehow.
For one, oil would be more expensive than water, you'd need an awful lot of it, and you couldn't really save it and reuse it more than a few times because you'd be risking contamination from rancid oil.
And then the sealing issue, as I already mentioned about oil getting between the rubber seal and the jar.
It would also be more persnickety. You'd have to sit there and monitor a temperature gauge.
As for timing... 240 degrees is 240 degrees, if your recipe says to process under pressure for 20 minutes, then I would assume processing at 240 degrees in oil would be about the same.
There might be very good reasons why it wouldn't work - I just haven't really heard any yet.
"seems like a possibility." Sure, it's possible, temperature-wise, since you can raise the temperature of cooking oil to 240° without pressure, unlike water without pressure, but the risk, cost and mess far outweigh the practicality of processing canned food in a hot oil bath. Is that what you want to know?
"Hand wring and haranguing about how it's just not done that way" Cautioning the OP against a possible hot oil boil over or explosion from a leaking jar is hand wringing? Under processed food is haranguing? There has been more concrete infomation passed to the OP about why this technique is not a safe one than the post deserved a response to in the first place. It's not done that way for a few very good reasons.
"I would assume processing at 240 degrees in oil would be about the same." You cannot assume anything when canning food. Would you consume Bolognese sauce just hoping it was properly processed?
There are no statistics for this method working or not, simply because there is no published research that I've been able to locate. Maybe there is no one very good reason why it wouldn't work, but there are quite a few reasons for not doing it.
I can't imagine what other evidence of this being a dangerous procedure you could possibly need that hasn't been outlined here. If it's a yay or nay concrete scientific explanation you want, contact your local agricultural extension service, which will tell you how to contact the food science department at your state's university, www.ucdavis.edu
Delarian, Yes superheated. If the oil is above 212*F it will produce an unwanted rapid boil off of any water based liquid that is introduced into it.
If you have a propane cooking eye, try it OUTSIDE. See what occurs when you pour a quart of H20 based liquid in 240*F oil. You will get a rapid vaporization of the liquid and thus a somewhat violent frothing and overflowing of the oil. This would approximate the event of a jar cracking or otherwise emptying its contents.
This treatment is insufficient to kill botulism spores; putting a food item into 250 degree oil at one atmosphere will still leave the boiling point of water at 212 degrees, meaning the interior of the food will be unable to rise beyond that until all of the water in the food is gone(and likely disintegrated).
The pressure canner works because it can raise the food in question to these temperatures while still maintaining your moisture content.
Wouldn't the boiling point in the sealed container rise as pressure builds, just as it rises in a pressure cooker that is heated past 212? In the OP's query, the can becomes the pressurized environment. Unless you're just talking about immersing foods into hot oil without a jar, but then we're talking low-temp frying, not canning.
BTW to the OP: that very fact that the can becomes pressurized while the oil does not is exactly why I also would not suggest trying this. You would run a serious risk of blowing up your pressurized jars, which as others have pointed out, would be quite dangerous and messy.
It would be a cool experiment to try under highly controlled conditions though (we're talking PID controlled oil temp, empty concrete lot, fire extinguishers, and no-one within 8 feet of the oil).
If temperature outside the canning jar were the only issue, you could use an oven. You could have the oil/air at 400 degrees and the liquid in the jar will only reach 212 because it will turn to steam at anything higher than that allowing for some variation due to sugar or salt dissolved in it and bubble out of the jar(or if it happened too quickly, explode). That is the reason the jar rings are not tightened down all the way. It requires a closed system with increased pressure to raise the temperature/boiling point to 240. On the other side of the coin less pressure decreases the boiling point. If you live in Denver the boiling point of water is about 10 degrees lower.
I agree with all the other posters that this is just an incredibly risky and stupid idea for the home canner along the lines of "Hey guys! Hold my beer! Watch this!"
Also, pressure canners vent steam. Vented steam evaporates and goes away. Vented oil, assuming it would vent, would pretty much prevent you from getting close enough to the canner to work with it, not to mention coating everything it lands on (including you). Think of the mess that happens when you cook fried foods. Now multiply that by oil spewed under pressure. And what happens inside the canner when your jars siphon into hot oil? Not to mention the oil will degrade and damage the various seals and gaskets in the canner. Just so don't go there.
I would really be worried about the jars sealing. In my opinion it's not worth the risk of food loss due to spoilage or illness due to botulism. If you are serious about canning and really want to expand your abilities then you have to go to a pressure canner in my opinion.
Here's a great article from the U of Georgia:
And here's a link to a review of the All American Canners which I think are the best!