Grove - 12 Key Capacitive feasibility inquiry for pellets detection

For my pellets stove, I’m thinking of creating a pellets level alarm (or more maybe a level indicator) using this capacitive sensor : Grove - 12 Key Capacitive I2C Touch Sensor V2(MPR121).

The big question is does such a sensor can be operated by the contact of the little wood pellets in the stove tank? It’s a chaotic stack of pellets. The idea would be to distribute along the height of the tank some detection patches. The patches could be some aluminium little plates (I think 2-3cm diam) connected to the needed CHx inputs of the Grove device.

When the tank is totally filled all patches would be in a “touched state” and as the stove consumes the pellets and their level is going down, some detection patches will become “untouched”.
(Goal it to trigger some led warning or whatever before the pellets tank runs empty)

Having a look at
I understand the lib feeds the inputs variable with a boolean for each of the 12 keys (untouched/touched).

So another question:
However I presume there must be some way calibrate the input physical level to determine if it’s actually touched or not because I suspect the contact with pellet won’t be regular and constant.

any suggestion appreciate
Thank you