can the degree of white to black parts make coarse ground pepper taste mild? I previously asked this question about what makes black pepper mild:  What makes black pepper strong or mild?

Both ground type and freshness could be the cause however it has occured to me that the parts in the mild bottle had more white than black bits.  I understand that white pepper(the inside of black peppercorn tastes different to the exterior black bits).  On the other hand when it has tasted stronger thats because I was using a pepper where it was predominantly black bits.

so could this be a cause for the mild taste?
Yes, the white pepper is the whole black peppercorn with the skin removed (and possibly fermented via a water soak). A lot of the pepper flavor is in the pepper skin (the black part) which is removed in the process of making white pepper. The compound that gives pepper its flavor is piperine which isn't found in the pepper berry as much as it is in the skin.