I need to know about canning in the oven. I have everything but the how long to leave in the oven? I know the temp is 200 just don't know how long to leave in the oven.
Lynn from Sarepta, LA
I know this thread is a little old but I thought it worth a comment anyway, particularly as it still forms a reference to those looking for information.
Firstly, I can't possibly see why food in a glass jar which is placed in an oven for long enough won't reach the desired temperature throughout. If I thought that it wouldn't, I'd never eat a roast chicken ever again !!! I'm a physics teacher and heat is transferred if there is a gradient i.e. like water, it will "flow" either up or down with time and temp difference. The bigger the temp difference the quicker it will flow. You need to realise that we are talking about heat flowing through the liquid inside the jar and not the air in the oven. Heat transfer through the air in the oven is irrelevant as it is already at the desired temperature which is then maintained by the elements.
Secondly, submerging the jar makes no difference to air bubbles rising. They will rise in an oven just the same as a water bath because they are contained within a jar. What's outside the jar (water or air) is again irrelevant.
Thirdly, if the lid isn't sealed the jar is NOT going to explode, trust me !! Why on earth would it. Glass is red hot when it's made in the first place and would only break in an oven due to either high pressure inside (if the lid were sealed) OR if the glass was thick and it was unevenly heated very quickly (thermal shock) i.e. if the inside surface was much colder than outside surface which would cause uneven expansion within the glass itself.
I do understand that some people might not follow the instructions properly and that Botulism etc. therefore could be an issue BUT that's the same situation whether the jar of food is placed in a water bath or an over.
Sorry to disagree with you all but if you are going to quote physics please get it right.
Oven-canning is extremely hazardous. The oven canning method involves placing jars in an oven and heating. In oven canning, product temperatures never exceed the boiling point because the jars are not covered. It is, therefore, not safe to use for low-acid products (e.g. meats, most vegetables) which require temperatures higher than 212 F.
Because this process fails to destroy the spores of Clostridium botulinum, it can cause the food to become toxic during storage. Also, canning jars are not designed for intense dry heat and may explode resulting in serious cuts or burn
I agree with the other poster. Do not try it. It's not safe. If you read in the Ball canning book it will tell you that it's not a safe or approved method of canning. I have always done the boiling bath method on top of the stove.
I agree with the above posters - DON'T DO IT!!!!!!! It is extremely dangerous. My mother tried it with tomatoes once - I threw them out. It's just not worth the risk!! A temperature of 200 is NOT hot enough.
I do agree with the above posts. I have heard about canning in the oven but want to be sure of tried and true methods of canning. It can harm you or the ones you love. Better safe than sorry.
I want to Thank Everyone for their responses and i will never do any canning in the oven. I will stick with on top the stove cooking.
Let me THANK ALL OF YOU again .
I have canned in the oven for decades. I have never lost a jar of food by doing so. The oven is 200 degrees and I make sure that each jar of tomatoes or beans, etc., is boiling and bubbling before turning the oven off. Prepare your jars, lids, and rings by first boiling them. They need to be hot when filled as you first blanche your vegetables for 3 minutes (then immerse tomatoes in a cold water bath - ice water, preferably- to get their skins removed). I bake the jars for 2 hours and keep watch to be sure each bubbles and boils. Leave 1" or more at the top for this when loading the jars. I remove the jars with canning tongs to towels on the counter and gradually tighten the lids as the jars cool. With green beans, I add lemon juice for acid in each jar. I have used the big canning water bath pot method and it ruined the top of my stove in a previous house as the pot overhangs the burners on the electric stove and ruins the porcelain around each burner. I will not use this method as I have a quartz glass top induction stove, which is gourmet quality. The oven canning method has always been perfectly safe for me.
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