Mildly interesting: my bean vacuum canister takes out ~0.4g of air
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This is very interesting. I think you just proved that the Planetary Design type canisters (adjustable volume instead of vacuum) are better. Hear me out.
Here commenters are saying that they did the math and about 1/4th of the air in the can is going out. This is independent of the can's fill level, since the limit is the pressure difference against which the can can pump.
Now, say the can is half full. That means half of it is pure air and half of it is a mix of air and coffee beans, depending on how densely they are packed. Assuming spherical beans and optimal packing that means about 25% of the remaining volume is air source. Therefore the Planetary Scape removes 80% of the air in the case where the can is half full. That is a lot more than the Fellow type.
It's easy to find the "break-even fill level" from which the adjustable-volume canister removes more air than the vacuum-type canister, that always removes 1/4th of the air.
If r is the portion of can volume filled with beans, that means that 0.25r this the portion of this volume that is actually air, and 1-r is the remainder. 0.25r+(1-r) is the total fraction of air. When the plunger is applied, 1-r is removed, and the 0.25r between the beans stays. The ratio of air taken out is (1-r) / (0.25r+1-r). This equals 1/4th when r=11/12. That is, whenever your can is less than 11/12ths full, the adjustable-volume canister removes more air than the vacuum-type canister!
Note, however, that a Ziploc bag would achieve the same. But that is another consideration to be made!
Tldr: just store your beans in a Ziploc bag and empty as much air as possible before sealing, you'll be better off flavor-wise and money-wise!
I've just tested the same canister without beand and I made sure to empty as much as I could out and got a difference of 0.82, need to see how that affects calculations
Ok, if I'm not mistaken in that case the break even fill level would be around 75-80%.