Making Meat: Algor and Rigor Mortis, Elusive Brothers of Tender and Tasty Game Care
You’ve heard of Rigor Mortis? Meet his younger brother, Algor.
Let’s start with the brother you know. Rigor sets in shortly after you’ve shot and killed whatever you are hunting, be it four-legged or feathered. It starts at the neck, then works its way down to the toenails, taking 10-48 hours, in moderate temperatures, to go back out.
Algor Mortis is the rate the carcass cools, after you’ve shot and killed whatever you are hunting. According to Mary Roach in her wonderful book Cadaver, in moderate temperatures, Algor cools at 1.5°F per hour. Then again, Newton’s Law of Cooling states that the larger the temperature difference between an object and its surrounding, the quicker it will cool.
Obviously nothing is precisely predictable (or moderate) in the outdoors, or hunting. Most Montanans would consider 30 pretty moderate on a sunny day. But I’ve hunted in Alabama at 30 degrees and the humidity makes that a lot less comfortable than Montana’s arid 30 degrees. Same with 80 degrees. And of course, when cooling game, humidity counts. For one thing, humidity holds heat and, while it may not hold heat in that carcass, humid nights don’t cool off as much or as quickly as dry ones.
What’s important is that you make sure the cooling happens, and within a certain period of time. From about 98°F down to a safe aging/hanging-out temperature, something like 40-45 degrees, in 3-4 hours.
So if the temperature outside is warm,
- Clean and rinse the carcass ASAP.
- Hang it in a cool, shaded place, root cellar, or cooler.
If it’s hot:
- Separate the quarters from the carcass. The Journal of Meat Science points out that the neck is always the first place to sour; so depending on how hot, front quarters are first priority.
- We always split the pelvis on all big game animals, no matter the temperature, and that helps cool the hindquarters faster.
If it’s really hot:
- Skin the animal. A lot of people skin the carcass right away no matter the temperature, but the skin provides a sterile wrap, keeping dirt and bugs from the meat. It also keeps that outside surface from drying out, which means less meat trimming later.
Living in Montana, it’s only bow season, usually, when the weather is hot enough that skinning is necessary to get the body heat down. The rest of hunting season is cool enough, we don’t have to go to that extreme and prefer to keep that sterile wrap in place. But in the southern US, it’s another story.
Now let’s add a few more variables: is the animal thin or fat? Bulky like a bull elk or svelte like an antelope or whitetail doe? (In forensics, they check the surface area to weight ratio as part of time-of-death calculation. They’re working backward. We’re working forward, but that ratio is important either way.) Is the wind blowing?
Here’s an interesting one: What position did the animal fall in? Years ago, a friend shot a whitetail buck in the last minutes of shooting light. Then couldn’t find it. It was the rut, mid to late November, at well over 5,000 feet above sea level. It was hovering below 0°F that night, and was still in single digits when a gang of us went out to find the buck. It didn’t take long in the light. Aside from not wanting a wounded animal to suffer, we were concerned about the quality of the meat.
Assuming the animal died–and our friend was a very good shot–we were concerned about cold shortening: since the night was so cold, and brother Algor Mortis would gallop, the carcass would freeze before rigor went out, a big factor in making meat tougher than it was on the hoof.
But that Twisted Sister, Mother Nature, did us a favor. The buck had died within 60 yards of the shot, and was lying in the shade of an aspen tree, looking like an African PH had arranged a trophy photo for us. His belly was flat on the frozen ground, his legs folded tight against his body keeping heat from escaping—too fast—from the vitals cavity, and that heat had kept him from freezing. But, given the ambient air temperature, he had cooled down. Enough. We couldn’t have done any better had we found him right away.
Yes, he was in rigor mortis, but brother Algor had broken the rules big time, not letting the carcass cool the 1.5°F per hour multiplied by below zero temperatures. Had the buck fallen on his side, we would have had a totally different outcome.
So last weekend’s antelope hunt? Great meat, in hand. We took a yearling doe and moderate buck, as our friend and landowner/outfitter John Stuver had asked us to, and did not have to skin them, quarter them, loosely arrange a bag of block ice in their body cavities, nor hang them in his cooler. A cold front, with much needed rain, had come in the night before: temperatures were in the mid-40s, and by 2 in the afternoon, when we took the antelope, was raining enough to make crawling through the long grass bracing, to say the least.
By the time we’d taken the photos, dressed them, and gotten the animals hanging in the shop, they were well on their way to cooling down quite nicely. The hunters, however, were quite happy to head indoors and put dry clothes on and sit around the fire, getting our body temperatures back up. And yes, in all the years we’ve hunted antelope, only twice have we had water issues. Many years ago, we hunted in hip waders: it had snowed, then turned warm. The gumbo was slick and every little drainage was running high and fast. But this was the first time we’d hunted antelope in rain gear.
PS: I used my new Tika .22-250, a special run ordered by Whittaker Guns of Owensboro Kentucky, with 70 gr GMX and 41 gr Hogdgon Superformance. John used his 6.5x57R JP Bauer & Sohn drilling, 129 gr Nosler Accu-Bond Long Range bullet, and 44 gr IMR 4451.
For a lot more info on game care, as well as 100 venison recipes, check out my book, Slice of the Wild. https://www.riflesandrecipes.com/product/venison-recipes/
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