Could you specify what about the emulsion made it "unusable"?
The above quotes are a bit garbled due to parsing, but....
Bad mixing will cause local hot spots which lead to something akin to pepper grain which is actually huge crystals that cannot be peptized by gelatin. This is known in the literature so I'm sorry that I didn't go into detail as I thought that it was known.
In any event, the emulsion has huge crystals that can be felt with the finger and are "crunchy". They give rise to lower contrast and big black blotches in the image.