It's the fat in the meat overheating and burning, doesn't really hurt anything, but toss out that last little bit. The KA grinder does a pretty good and efficient job grinding, you have to cut up your product somewhat small, 1 to 1 1/2" size cubes. Stuffing, however, is quite slow. It can be done, I used one for a couple years, but it takes patience. I ended up buying a 1 hp. grinder from Cabela's for $349. Even then it didn't stuff as well as I'd liked, as it chewed up the meat in the auger. I finally just got a 15lb. Stainless steel stuffer from Northern Tool that is the best - cranks out sausage in casings like a champ and no degredation in the meat; it's nice and separated between the fat and lean, not partially emulsified. I paid $169 for it on sale this summer, it's regular $199, which is still half price from most other places, most are $399 to $499 for it. Now, if I can just talk momma into a mixer to hook onto the grinder... hahah.. never enough, y'know?!