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?
Might slow it but I don’t think any hopper that’s specifically designed to do it is going to be airtight from the bottom where the coffee is ground, so new air will enter from there.
The smaller opening would help, of course, but a complete seal isn’t gonna happen without the cooperation of that end.
Ah, there is another idea for an entrepreneur. Sealing the bottom between uses. I haven’t tested this, but instinctively I think not much air will push its way up compared to the air sucked in from the top as beans drop.