I couldn't really find anything online about it, and I ended up figuring it out (i think
Cause:
Mills continue to produce flour even after you have
met your quota on bread. (As long as there is wheat
available.) So if no one is eating your bread, then
you continue to produce flour, causing a massive
overstock of flour.
Solution:
Lower Wheat Harvesting to 1, and raise bread production
slowly until you have a decent balance of flour to bread.
If you are feeding a massive population on bread, you may
need to raise wheat harvesting to 2 or more. Adjust
your bread production accordingly.
Does this sound right? Again, I am pretty new to this game.

