Why do you need to add boiling water to the pot to can food
by
Susan
+4
what's the difference between putting the jars in cold water and bringing to a boil versus adding boiling water to the pot?
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You need to get the contents of the jar to a high enough temperature to avoid spoilage. Starting with cold water may give inconsistant and danger results.
If you are using a hot water bath you do not bring the jars to a boil with the hot water bath, so you use hot water so there is not a great temp change that causes jars to break when you put them in the canner to process. I do not have it boiling, but too hot to touch is good. It needs to be at room temp, at the very least, and it can still be a shock to the jar.
But if you are asking why to add hot water to an already boiling canner, its so the process time isn't messed with. If you add cold or room temp water to a boiling canner it will stop the boil and stop the processing time. You need to make sure the jars are covered well, by at least 2" of water, so the pressure causes excess air to escape and the heat gets hot enough at the core of the jar to safely process. If I still have not answered your question please let me know. I love canning, I can everything from meat to potatoes and everything in between, and love to help someone willing to do it. Its becoming a lost art!
If food in jars is hot already then your jars may shatter if you add them to cold water. If the jars & contents are cold then it is best to use cold water as again the change in temp may cause the jars to shatter. If you are using cold just time from when the water starts to boil.