[quote author=Aragorn]
Finduilas495, you may be aware of this already, but I'm posting this just in case you don't. I'm not sure what you're canning, but if you're canning meat in any form waterbath canning isn't recommended for safety issues. I know that some say it's propably okay - if you boil the jars like 5-6 hours, but if you want to stay on the safe side of botulism poisoning, please use a proper pressure canner (not cooker!). Botulism spores are known to be killed only at 116C (yes, the "live" botulism bacteria are killed at lower temperatures but not the spores), and that temperature you can't reach with normal boiling. This is stated in every reliable source on canning that I've read. The pressure cookers are not recommended either, because they heat up and cool down too fast, making the time of processing shorter.
I'm also pretty sure that using jars with a rubber ring and glass lid for canning (meat) poses a risk: since the lid isn't visually depressed because of the vacuum, it's harder to tell if the jar has remained sealed. If in doubt, throw it out - as they say. It's also good to boil the canned food for 10-15min before eating.
For mor info, see:
-The Ball Book on Home Preserving: _http://www.scribd.com/doc/53643541/The-Ball-Book-of-Home-Preserving
-How do I can meats? (National center for food preservation): _http://nchfp.uga.edu/how/can5_meat.html
-Canning / Sterlization of meat products: _http://www.fao.org/docrep/010/ai407e/AI407E22.htm
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Thank you for the information, Aragorn
I am aware that the temperatures in a waterbath canner are too low for raw meat, but according to the canning recipes I found in some German cookbooks, it is supposedly safe if the meat is pre-cooked. I chop the meat up, add salt and pepper, fry it in lard, simmer it with some added water until thoroughly cooked, and then fill it in the glasses. Then the glasses go in the canner. The glasses I use open if the food is off, i.e. there is no vacuum in the glass. I check the glasses right after they come out of the canner, if the lid comes lose (very rarely), we eat the contents the same day.
I agree that if a glass out of storage opens, I would throw the contents out, that hasn't happened so far though. We tried a glass that's about a year old recently and it was delicious.
That said, I do intend to invest in a pressure canner in order to speed the process up.