pressure cooker/canner?

[spitfire]

Hello everyone, hope someone can help with my question. I have an 8qt pressure cooker that i cook soups etc. it has a peforated rack for the bottom, says it's for steaming and keeping flavors seperate whem steaming more than one food.
My question is this: can i use this pressure cooker for canning homemade soups, veggies from the garden etc?

[MKG]

I can't think of any reason why you shouldn't be able to. It's the temperature which is the important thing, after all, and all pressure cookers will produce pretty high temperatures.

Mike

[spitfire]

I just re-read my instruction booklet and it say's that my pressure cooker is 15lbs of pressure and 250 f. so i think i will try my hand at canning with it. hopefully it will be a success any suggestions on what veg i should start with? what cans best? any help will be great. thanks

[Durgan]

Hello everyone, hope someone can help with my question. I have an 8qt pressure cooker that i cook soups etc. it has a peforated rack for the bottom, says it's for steaming and keeping flavors seperate whem steaming more than one food.
My question is this: can i use this pressure cooker for canning homemade soups, veggies from the garden etc?

Pressure cooking fresh vegetables if rather iffy, since one often ends up with mush, since the cooking time is so very short.
The small perforated plate in the bottom is almost useless for many types of material, like dried beans and peas. This material often boils up and plugs the whistler, and the safety plug blows and you end up with a half day of cleaning the ceiling.

Here is what I use.

Pressure Cooker

http://www.durgan.org/URL/?YUMUN 10 November 2008 Pressure Cooker

The old Presto Pressure Cooker was replaced. The new one is 8 quarts and the old one still functioning after 30 years was 5 quart. The construction is basically the same, but the new one is polished aluminum, which won't leach aluminum as much as the older type material.

A large percentage of my cooking is done with the pressure cooker. With a bit of practice cooking is quick and food retains more nutrients.

For an insert a colander is utilized with the handles knocked off. All pressure cookers should have an insert to prevent water from touching the material being cooked, and to prevent material from bubbling and clogging the pressure ports.

There are several Pressure Cookers on the market, but with ridiculously complicated locking mechanisms, and peculiar ports. Caveat emptor!

[MKG]

I decided I didn't like my last answer (a bit off the top of my head), so I did a bit of Googling.

You definitely need the rack/perforated plate to prevent direct heating via the bottom of the pan.

There are an awful lot of pressure canner manufacturers on the net busily telling the world that you cannot can in a normal pressure cooker. There are just as many pressure cooker manufacturers busily saying that you can (The truth - you certainly can can - ).

You must be able to reach a temperature of 240 degrees F and sustain it for 10 minutes. (240 degrees is the equivalent of Richie's 10psi). Just about every pressure cooker set up for normal operation will attain 254 degrees F (which is twice normal atmospheric pressure), so no problem there. Start the ten minute count only when the cooker has come up to full pressure, and Bob's your auntie - you now have fully sterile contents.

Na, nananana naa naa nananana naa naa nananana nananananananana ........

Mike

[spitfire]

DURGAN, i don't use the perforated plate when i cook with the pressure cooker. I was just wondering if it would be needed for canning to keep the jars off of the bottom, I looked at the pic's of the one you use and it is the same one i have a presto 8qt Do you use yours for canning?

[Durgan]

DURGAN, i don't use the perforated plate when i cook with the pressure cooker. I was just wondering if it would be needed for canning to keep the jars off of the bottom, I looked at the pic's of the one you use and it is the same one i have a presto 8qt Do you use yours for canning?

I have used a large pot which takes six, six liter jars, which are supported by a wire carrier. This is simple and convenient.

Jars empty are placed in the canner and boiled for about ten minutes to sterilize. The material that is cooked by any means including the pressure cooker is poured into the jars. It should be hot. Fill the jars and put the sterilized tops (boiled in water about ten minutes) on the jars.The jars are placed in the canner with water covering the top of the jars. Bring to a boil for about ten minutes. Remove the carrier and let cool and store. The objective is to be as clean as possible, and to kill any residual bacteria.

http://www.containerandpackaging.com/homecanning.asp Look at the third picture from the top.

I see no advantage in using a pressure cooker for canning, other than cooking certain foods.

Usually I cook soy beans, but don't take such elaborate precautions, since I eat the filled jars in less than a week, and bacteria if present doesn't form in the short interval.

[Durgan]

DURGAN, i don't use the perforated plate when i cook with the pressure cooker. I was just wondering if it would be needed for canning to keep the jars off of the bottom, I looked at the pic's of the one you use and it is the same one i have a presto 8qt Do you use yours for canning?

It is necessary to use an insert to keep the food from the water and to prevent foaming. The steam cooks the food. If water is needed for the food, then add it later in another pot and boil to mix for a few minutes. The lid of the pressure cooker should never be used, since loose on a pot will destroy the sealing gasket, which should last forever.

If you cannot find an appropriate colander use this Collapsible Vegetable Steamer insert. http://www.cooking.com/products/shprodde.asp?SKU=117046

[MKG]

Now, I'm not a canner or bottler of any great experience. But I think that this discussion may be running at cross purposes. Durgan, I think you're advocating the water-bath method of canning whilst you, Spitfire, are asking about the high-pressure method. As far as I can see, the water-bath method is suitable ONLY for high-acidity foods. Tomatoes are certainly successful using that method (even I've done that).

But Spitfire's original question was "can i use this pressure cooker for canning homemade soups, veggies from the garden etc?"

That doesn't imply high acidity, unless I'm missing something. I began this by saying I'm not a canner, so I'm open to correction - but the balance of expertise I've managed to read in the last few hours would tend to lead me to believe that there is an inherent risk in not attaining that 240 degree temperature for 10 minutes as far as low-acidity foods are concerned, and the inherent risk is botulism - pretty serious stuff.

The water-bath method cannot possibly achieve temperatures above 212 degrees F. High-acidity foodstuffs, simply because of their acidic nature, are resistant to microbial attack - not immune, but resistant. Not so low-acidity foodstuffs. If such foods are used fresh, there hasn't been enough time for a colony of any micro-organism to reach dangerous levels - but canned or bottled foods are kept for much more extended periods of time.

Normally, I'm a bloke who argues for what I see as logic, and I must admit that I haven't quite seen the logic in the 240 degree scenario as opposed to the 212 degrees scenario. But the fact remains (and this is what makes me uncomfortable) that I can't find anything anywhere which suggests that anything other than the high-pressure method would guarantee that I would achieve sterility within a closed container.

Given that I'm no expert, though, I think I would decide to err on the side of caution. I'd use the one bit of my knowledge of which I'm sure - most garden vegetables are low in acidity. I'd use the pressure method - at least then I could sleep at night.

Mike

[Jandra]

Here's how it is: the spores of the botulism bacteria survive at normal cooking temps. So water bath cooking will not kill them. in high acidity the spores won't ever grow to make more botulin (= the botulism toxin), so no problem there. Low acidity, low oxigen conditions are botulism paradise, unless you can be sure you've killed off all the spores. In my research on the web I've learned that they won't survive temps of more than 121 C (20 minutes). Many pressure cookers will not reach these temps. I've especially purchased one that had 'pressure canning meat' described in the manual. It's a Fissler. In general, the larger pressure canners sold in the US might be the better option. They are bigger, allowing you to can more bottles in one heating sessions and they reach higher pressure (= higher temps) than regular pressure cookers. In the US they are obsessed with food safety and that's not all bad.

By the way, botulin becomes chemically unstable when it is cooked for 10 minutes and will explode in your face... eh.... fall apart and become quite harmless (really!).

In case you don't exactly know if botulism is such a problem... it's really not a stomach upset or something like that. 0,000000015 grams is sufficient to kill a human. The toxin prevents signal from the nervous system to be transmitted to the muscles. Typically 10-20 hours after eating infected food symptoms begin and eventually the person may die when the respiratory muscles become paralyzed.
From Wikipedia "Outbreaks of foodborne botulism involving two or more persons occur most years [in the US] and are usually caused by the consumption of home-canned foods." So the risk is not imaginary nor marginal.

Jandra

[spitfire]

jumping jehosafat, my wee head is spinning too much info not enough time---- no, wait thats tooo much time, not enough beer thanks everyone for the information. I think i will try to stick to the high acidic foods for canning right now and maybe blanch and freeze the other stuff with my food-sealer. i have some tips to share on that front but i will save them for later

[Durgan]

Here's how it is: the spores of the botulism bacteria survive at normal cooking temps. So water bath cooking will not kill them. in high acidity the spores won't ever grow to make more botulin (= the botulism toxin), so no problem there. Low acidity, low oxigen conditions are botulism paradise, unless you can be sure you've killed off all the spores. In my research on the web I've learned that they won't survive temps of more than 221 C (20 minutes). Many pressure cookers will not reach these temps. I've especially purchased one that had 'pressure canning meat' described in the manual. It's a Fissler. In general, the larger pressure canners sold in the US might be the better option. They are bigger, allowing you to can more bottles in one heating sessions and they reach higher pressure (= higher temps) than regular pressure cookers. In the US they are obsessed with food safety and that's not all bad.

By the way, botulin becomes chemically unstable when it is cooked for 10 minutes and will explode in your face... eh.... fall apart and become quite harmless (really!).

In case you don't exactly know if botulism is such a problem... it's really not a stomach upset or something like that. 0,000000015 grams is sufficient to kill a human. The toxin prevents signal from the nervous system to be transmitted to the muscles. Typically 10-20 hours after eating infected food symptoms begin and eventually the person may die when the respiratory muscles become paralyzed.
From Wikipedia "Outbreaks of foodborne botulism involving two or more persons occur most years [in the US] and are usually caused by the consumption of home-canned foods." So the risk is not imaginary nor marginal.

Jandra

Nice summary. I never can low acid food. But in the past I did know about the danger of relying on the water method of canning. The commercial caners ruin food by the excessive heat, necessary for botulism safety. and it takes a bit of necessity to eat such food. Thanks for the reminder.

[Jandra]

Oops, reading Durgan's reaction I discover a typo.

Off to edit my original post and decrease the temp from 221 to 121 C....

Jandra