I’ve been wondering if something sitting on top of the beans in the hopper (eg a bag of rice) would stop new oxygen reaching the beans as their level drops. Ideally, the hopper would be cylindrical and the object a simple disk, but mine is the usual conical shape. Or am I over-thinking this?
I would think that a plastic bag of rice is anything but porous.
IME storing beans in a foil bag that I open and re-open every day accelerates oxidation even though I roll the top to expel all air. I suppose this is less noticeable if the bag runs out very quickly.