So I have asked my roommates, who don’t can, to pretend they were interested in canning and give me some questions that a new/novice canner might have. There will be a series of posts covering these questions. If you can think of one that I don’t cover please feel free to post it in the comments of any of my FAQ posts. These posts will also be linked from my FAQ page.
The first question they came up with, and I think it’s a good one, is “How hot does the water need to be?” This question actually requires a non-answer.
That non-answer is well that depends. Are you doing a water bath canning process or a pressure canning process? Also it doesn’t really matter how hot the water is.
You see you don’t get the water to a certain temperature and then drop in your jars. If you’re doing a water bath canning process you start your process time when the water comes to a full rolling boil. You might ask what a rolling boil is.
A rolling boil is so aggressive that it cannot be disturbed or disrupted by stirring, or by dropping ingredients into the water. What that means is that you can stick a spoon in the water and stir till your arm falls off but the water will still be boiling.
If you’re doing pressure canning then you never actually get to see the water boil. However because increasing the pressure causes the water to boil at a much higher temperature than normal, normal being 100°C (212°F), you get a hotter boil than you would in a regular water bath canner.
Either way you need a boil. How hot the water is just depends on the pressure it’s under. For example I live at about 5,000 ft above sea level. That means that water boils at a lower temperature here than it does down there. So when I process in my water bath canner I have to process for longer times. If I had a pressure canner I would have to put a heavier weight on the canner or let the dial get to a higher pressure before I started my timer.
Just make sure you always get your water to a boil, or your pressure to the right weight, before you start your timer and you’ll be golden. Your food will be safely processed for shelf stability.