The Kid,
Posted this not too long ago on another Campfire forum:
The scientific term for what can sometimes toughen boned meat is "shortening," because the muscle cells actually contract when disconnected from the bones. This can also happen even when left on the bone, if the meat cools down too quickly, especially when it goes from warm to freezing in a few hours, which these days is called "thaw shortening." I had this happen to an eating-size mule deer buck here in Montana one Thanksgiving. We hung the field-dressed carcass on a corral gate to cool overnight, and the temperature dropped below zero. The toughest deer I've ever taken! Even hanging the carcass for several days after it thawed didn't tenderize the meat much.
The warm-meat problem is due to rigor mortis, which is also essentially a muscle contraction. If the muscles start to go into rigor before the boning occurs, then the meat can toughen due to the contraction. Oddly enough, this is more likely to happen in warmer weather--which is when many hunters bone out animals, to "cool 'em down." Warm temperatures accelerate the chemical process of rigor, while cooler temperatures slow it down.
The other factor, of course, is the tenderness of the individual animal. Wild animals are not a consistent "product," like domestic meat sold in stores. They vary considerably in age and condition, and younger animals have less of what is called "organized collagen," the protein fiber that makes meat tougher--which is broken down during the chemical process of "hanging" game. Some species develop relatively little organized collagen even as they grow older, such as pronghorns, so "shortening" doesn't affect their meat as much. In fact we've boned out quite a few freshly-killed antelope with no problems.
Other animals can be affected when boned out, depending on their age and how far rigor mortis has progressed. It's better to bone them before rigor even starts, or after it has dissipated--which normally takes at least a day, though again, temperature affects the chemical process.
As a matter of fact, we've been timing the rigor-mortis process with a mule deer doe I took last week, because my wife Eileen writes game cookbooks for most of her living, and wanted to get some precise results. So we put a thermometer out in the garage, and checked the doe (an older, bigger one) periodically, starting two hours after it was killed. Eileen will probably write it up for our on-line magazine, RIFLE LOONY NEWS. We'll probably take one or two more deer this season, and will repeat the "experiment" on them.
