Deer (or other game meat excluding pork) fat doesn’t taste good. A proper burger (in my opinion, and I’m something of an enthusiast) contains only meat and seasoning, the meat ideally with something like a 20% fat content. Venison isn’t ideal, need to add fat. I haven’t managed to find a good source for fat to add to venison mince but I haven’t tried too hard yet. So I just buy beef mince for burgers.
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