In my opinion, the grind is by far the most important thing in a meat market. It's one thing that you actually have total control of. That is unless "the meat gods" send you crap you didn't order. The grind can make or break a meat dept. That's one thing that you really get judged on. Not everyone buys expensive steaks, but all meat buyers buy ground meat. Your cheapest beef grind is very important (as are all grinds), your 20% (22?) your fattest one, whatever you call it (It used to be 30%), but I don't see it out here these days. For a good grind, you need to all be on the same page, and everyone who takes part in the grind has to care about it. It's very simple, but it only takes one day, one person, to screw it up badly. Common sense you'd think, but I've seen a lot of people who should know better ruin a good grind system. Most important, is not to over grind. It may take more time, but grind more than once a day if you can. I know it's neat to try to get it all perfect the first time. Make a huge grind and it's just enough for the entire day. But I say try to grind at least twice. More is better, especially with a conventional case. Try to run out each night. That's the best thing you can do, almost run out totally. It can take more than two days to correct one day of over grinding. 2nd and almost the same, don't over cut. I've seen times when the lean grinds were 100% old steaks & roasts. That means the next day, your next in line lean trim is at least two days old. And what about yesterday's trim? Another problem is people who think they are a fast meat cutter, but while cutting so fast, they don't take the time to make the trimmings lean. That's when it becomes difficult to sell all the trimmings. If you're over grinding and over cutting, and not making your trim lean, you're in real trouble. But assuming you're doing everything near perfect, the grind will still turn dark on you. I'm not an expert on why it happens, but I do know that a grind out of control, grind gone dark because of the reasons listed above is worse way than fresh grind gone dark for reasons related to oxygen & light.