I came across a lovely old recipe. No pectin, no sure-jel…
6 lemons (I used meyer lemons)
6 cups sugar (I used cane juice crystals)
2 Tbsp vanilla (I used the vanilla I make)
Cut the ends off the lemons and then cut them VERY thin. Remove any seeds and then cut each slice into 4 pieces.
Add 5 cups of water.
Bring to boil and then turn heat down and simmer for 45 minutes
Add your sugar and vanilla, continue to simmer at least 45 more minutes.
Mine took considerably longer, but it was rainy/snowy and I believe that made a difference.
Now, the ‘old-fashioned way’ to check for gelling is that you put a little bit on a plate. If the jam runs… cook longer. If it has resistance, then it’s ready.