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I'm confused about canning pressures!

Posted by Janellk64 none (My Page) on
Sun, Jul 15, 12 at 19:14

If the recipe calls for 11 pounds for 55 minutes....does it matter if I use 13 pounds? Does it matter if I do it a little longer? I can't seem to find the answer!!
thanks for the help

Follow-Up Postings:

RE: I'm confused about canning pressures!

when recipes state X pounds for Y minutes, these are based on minimum safe temperatures ( higher pressures = higher steam temperatures ) and minimum exposure times to kill off bacteria etc. Thus higher pressures and longer times don't pose a food safety risk ... although they may have some effect on the 'end product'.

RE: I'm confused about canning pressures!

Thanks...that makes sense. It's my first canning experience and my manual is not written for the novice canner.

RE: I'm confused about canning pressures!

Janellk64 - we never recommend using the canner manual for canning info - cooking fine - canning no. Just for the reasons you discovered. They are difficult to understand and even worse, downright wrong in some cases. They are often not current either.

The best online source is NCHFP linked below and they have a great step-by-step How to Use a Pressure Canner Guide. And the Ball Blue of Canning is the best basic canning cookbook.

As already mentioned doing it longer or at a higher pressure isn't a safety issue but it can be a quality issue so there is no reason to do it. Why not tell us exactly what it is you are trying to can and which brand of canner you have and if you have the weight (as recommended) or only a gauge. We can help.


Here is a link that might be useful: NCHFP

RE: I'm confused about canning pressures!

I have a Presto Pressure Canner/Cooker that I bought last month. It has a dial for reading pressure so that's good.
I was trying to can whole kernel corn but unfortunately I have an electric stove so regulating the temp is always a difficult task for this type of cooking.
Also...when I tested the canner yesterday to get familiar with the process it said the first time to vent for 10 minutes....but it didn't say to do that every time you use it. Fortunately I did find that info but after I had already began the pressure process. The jars seemed to seal just fine so I guess I was lucky. Altough I will say they are still very hot (it's been a couple of hours) and they are still showing some bubbles.

RE: I'm confused about canning pressures!

Dial gauge canners are not considered accurate unless the gauge is tested annually. Which is why we always recommend buying the optional 3 piece weight set and using it as a weighted canner instead. Weights are much more accurate.

The venting - you always vent for 10 mins each time. If you did not vent then the corn may be underprocessed. Check the step-by-step guide I linked above and let us know if and how much you deviated from it. Corn can be quite risky if not done properly - not usually a first attempt food - and just because the jars seal doesn't mean it was done properly.

Also did you adjust for altitude?

Learning to manage the burner takes a bit of practice runs and is best done with jars of colored water rather than food until you get it pegged.


Here is a link that might be useful: NCHFP - Pressure Canning

RE: I'm confused about canning pressures!

Even a brand new gauge must be tested before you use it. They are often off by as much as 4 lb. right from the start.. Meaning that gauge could be unsafe to use.
Then, as was said, if you did not vent it for the full 10 min. your food is underprocessed and not safe.
Plus, you do have to know what your altitude is and adjust if you live above 1000 ft.
Another good piece of advice, if you have a coil electric stove, you need a special canning element or you will ruin your stove in time. Trust me, I learned the hard way 2 times before anyone ever taught me this. Very expensive lesson to learn.

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