^^^^^^^^^^I agree with Inda, I have a LEM Big Bite grinder and every time I grind meat for burger and am in a hurry and don’t par freeze the meat I get that black stuff in the center of the plate From the fat being to warm. When I make sausage or salami I always par freeze the meat and never see the black stuff. I’ve seen the black stuff with other grinders as well but always when the meat was cold but not par froze, I believe this to be a very important step to a quality grind. Plus the slightly frozen meat keeps the knife, plate and auger very cold this is important for a premium grind and particle definition.