DelaWhere used to talk about oven canning too. I could never quite understand the scientific process that caused the lids to ‘ping’ when no air was removed, so I’ve never done it myself. I’ve only used the oven to kill critters before adding an oxygen absorber.
I have wheatberries stored, not flour, because the wheatberries last for decades and the nutritional value of flour the highest right after being ground. The hard shell around the wheatberry is nature’s perfect encapsulator. We probably don’t even need to go the extra mile of using oxygen absorbers and mylar - wheatberries have been found in Egyptian tombs and were still edible.
Pretty neat idea with the candle! Sounds like an old-fashioned remedy that is still valid today.
Th oven thing, I assume it is the heat that causes the jars to seal. I made some applesauce a few months ago, and it was so hot when I put it in the jars they sealed all by themselves, without traditional canning.