How to prevent scorching and sticking when boil soy milk
My understanding is that the soy has to come to the boil, and be held there for several minutes to deactivate enzymes.  I hear you.  I hate the clean up after making tofu.  You can certainly avoid burning by stirring and controlling the heat, but the lees will stick to the bottom and sides of the pot. I don't think there is any way around it, unless you use a non-stick vessel of some sort.  I don't have access to that, so, my solution is simply get water into the pan right after the straining, and clean as soon as possible.  A scouring pad of some sort really helps, but it takes some effort.