Recently I noticed something interesting about Kirkland's coffee bean. After I ground the bean and dump on the paper filter, some fragments actually stuck to the wall of the filter - as if they were attracted/pulled by the wall and partially overcome the gravitational pull, instead of simply staying at the bottom.
I noticed this couple of month ago, over time, I observed and can confirm that: this did not happen with other brands of beans - so I do not think that this is caused by the paper filter or the grinder.
Not sure whether the ground bean is necessarily electronically charged, but that certainly can be a potential explanation.
Does anyone know what caused this?