I've canned several things, but this time I think I have the required pictures. Yesterday I made apple pie filling. It took most of the day, although I will say I was also making roasted applesauce and doing some other things, like making carnitas. The key thing about canning pie filling is that you have to have the right sort of starch. Ordinary corn starch, or flour, is not good for canning. I used the recipe on the back of the starch bag, to be safe and also because it was exactly the same recipe as 3 other places on the interwebz when I went looking for alternatives. Canning recipes are that way - you don't mess with them.
The recipe called for 6 quarts of sliced apples, but that was not enough. Maybe they meant 6 quarts after blanching? For this recipe, you peel and slice the apples (that's the time consuming part) and then blanch them in small batches for one minute. They end up smaller and softer, but not fully cooked. Anyway, I did not get 7 quarts of pie filling. I got 5 and a half, and then that 6th jar got filled to the brim with leftover goo. I made a lovely apple cobbler with the leftover, utilizing several more apples.
I usually lid the jars right after I fill them, but I was dealing with the "not enough apples" problem so I had them all still open, on the rack over the boiling water which helps keep pathogens away. Half inch head space, per the recipe. I had a bit of siphoning (where preserves come out the lid either during or after the water bath) but not too bad. I left the jars sitting in the water for 10 minutes after the time was up and I turned off the burner, and then I let them sit above the water another 5 minutes as I'd been warned that apple pie filling is known to siphon.