How fast does meat cool down?

[Larry Bartlett]

Anyone know the laws of thermodynamics as they apply to cooling rates for game meat?

I'd like to share what I know because i think it's helpful, but would like to learn what hunters south of Alaska observe with game meat cooling rates in warmer environments.

larry

 

[daddie63]

I have no idea but look forward to hearing your info on this subject.

 

[Battleguy]

The key to having good venison is the care after the kill. Generally speaking it is best to field dress the deer fairly soon, cool it down, protect it from the blow flies, etc. The actual timing of this is probably dependant upon the outside air temps. The warmer it is outside, the quicker you need to get the deer dressed and cooled.

Keep the deer out of the direct sunlight and away from anyplace that would cause heat or keep the deer from cooling quickly. Laying/leaving the deer in the hot bed of a pick up truck or on the hot hood is a No No. Obviously, chilling the deer in a large ice chest or walk in cooler would be best if hunting during very warm weather.

Having an experienced deer hunter or processor show you how to properly field dress and process the deer will help a lot and speed up your learning process. It is not difficult, just a few basic things you to avoid such as don't bust open the guts, stomach, or bladder with your knife and spill those contents on the meat. After field dressing, wash the inside and outside down very well with lots of fresh water, removing any/all body fluids, dirt, hair, etc. I trim off any/all bloodied meat around the wound.

Properly field dressing, leaving hide on, and hanging the deer in a walk in cooler at about 38 degress for about 21 days is the best thing you can do for venison.

Good luck.

 

[Bulldawg]

Yeah, Larry knows more than most on all this haha.

For me I don't know times for what it takes to cool down, but I do believe that there is a little bit more time between death and spoilage than most think. And in Colorado where I hunt for elk there is more time that meat can be hung in the shade. What I'm saying is, I think that meat cools down fast without hide and fat when it's hung over night and doesn't warm up during the day even when it gets up to 70.

The key to having good venison is the care after the kill. Generally speaking it is best to field dress the deer fairly soon, cool it down, protect it from the blow flies, etc. The actual timing of this is probably dependant upon the outside air temps. The warmer it is outside, the quicker you need to get the deer dressed and cooled.

Keep the deer out of the direct sunlight and away from anyplace that would cause heat or keep the deer from cooling quickly. Laying/leaving the deer in the hot bed of a pick up truck or on the hot hood is a No No. Obviously, chilling the deer in a large ice chest or walk in cooler would be best if hunting during very warm weather.

Having an experienced deer hunter or processor show you how to properly field dress and process the deer will help a lot and speed up your learning process. It is not difficult, just a few basic things you to avoid such as don't bust open the guts, stomach, or bladder with your knife and spill those contents on the meat. After field dressing, wash the inside and outside down very well with lots of fresh water, removing any/all body fluids, dirt, hair, etc. I trim off any/all bloodied meat around the wound.

Properly field dressing, leaving hide on, and hanging the deer in a walk in cooler at about 38 degress for about 21 days is the best thing you can do for venison.

Good luck.

 

[Larry Bartlett]

Hey y'all, thanks for adding some value to this discussion.

I usually document temperature readings a few times each day in the field, then get hyper focused on temperature readings once the harvest is down. This has given me some extremely helpful data to share regarding meat care and managing game meat storage-temperature expectations.

Instead of verbalizing every point, i scanned six data sheets from 2007 to present day which details temperature and time from the time of death (moose/caribou) to exit from the field. Might want to download and save the files for future use.

The jest of what the data reveal is that game meat begins its post death journey from roughly 101 degrees F (normal core body temperature for ungulates) to a range of "mean daily temperature" very predictably between 36 and 48 hours post dismemberment.

You'll notice a wide range of temperatures on these hunts...some conditions provide low constant temps and some offer wide fluxes in day/night temp ranges. Take a look at this info and maybe fire off some points of interest to discuss?

Larry

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[Larry Bartlett]

Here are the last three data sheets from the above:

LB

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[Takem]

Thanks for sharing this. I couldn't get any of the attachments to open.

 

[Larry Bartlett]

I saved these files on my desktop and edited the attachments. Lets see if that worked better for viewing.

Instead of operating with a scientific formula for thermal mass temperature gradients, these graphs provide the basic scientific info any of us can use and remember to dial in our meat care practices.

It should also be stated that I performed every possible step to reduce core temperatures and shield from UV, warmth and moisture...so consider the average "hands off" approach to meat care and how this might prolong the stabilization of core temps by matters of 8-12 hours in some cases. Meaning, the same conditions with inexperienced hands might take the meat slightly longer to stabilize near the average daily mean temperature. Since i haven't tested a hands off variable, i'm not sure how much time and temperature may vary from my results to someone with less experience.

Hit me with questions if you got 'em, it's for everyone's gain.

LB

 

[rayporter]

lots of questions but I don't know what exactly to ask.

suppose the temperature never gets below 50*
just what temperature will the meat be "safe"

a bud was caribou hunting in Canada and they lost several animals in hot weather. they would not immerse the meat in a cold lake because they did not want to get the meat 'wet'. so it turned green before the plane arrived.


have helped recover 2 deer shot in the evening with temps at freezing and over night the temps were in the teens. both were found early in the morning and both were already green. in a way this is not relevant -just saying that you still have to take some precautions even if it is cold.

 

[Larry Bartlett]

Yes sir, temperature around the meat and temperature inside the meat are vital to understand.

The graphs above provide an expectation of how fast meat temps will fall AFTER removed from carcass (heat source) and when to expect to have core temps match ambient temperatures (within a couple of degrees).

regardless of outside temps and if the meat stays whole on the carcass overnight before dismembering means autolysis is accelerated post death because heat retention was held for many hours before getting hands on. Bone sour rancidity only takes about 6 hours with inner temps between 85 - 100 degrees F. If entrails remain intact even in freezing outside temps, an overnight recovery delay usually does not bode well for meat quality.

If daytime temps are 70 degrees and nightttime temps reach 30 degrees, your expectation at this range will be closer to 52-54 degrees. If the mean average temperature is above 55 degrees then hunters must pursue alternative means to cool meat to prevent bacterial invasion.

If core temps are above 50 degrees and there is a cold water source nearby...cool is more effective than wet concerns. Cool is more important than Dry concerns.

Temperature and moisture control spoilage bacteria, but first response priority scale is COOL by any means necessary, especially critical the first 48 hours post death.

hope this helps

 

[Kevin Dill]

I'm 100% in the camp of COOL IT first. Nothing beats cold air bathing hanging meat 24/7. I'm serious enough that I've added a digital instant-read thermometer to my gear. I would always prefer to air cool, but in questionable conditions I have no problem immersing raw meat in cold (hopefully moving) water long enough to get it cooled. I really think the only way to not guess at your meat temps is to measure them in the field periodically. The instant-read thermometers like Thermapen and others sold by ThermoWorks are ideal for this task. Thanks Larry.

 

[EastMT]

lots of questions but I don't know what exactly to ask.

suppose the temperature never gets below 50*
just what temperature will the meat be "safe"

a bud was caribou hunting in Canada and they lost several animals in hot weather. they would not immerse the meat in a cold lake because they did not want to get the meat 'wet'. so it turned green before the plane arrived.


have helped recover 2 deer shot in the evening with temps at freezing and over night the temps were in the teens. both were found early in the morning and both were already green. in a way this is not relevant -just saying that you still have to take some precautions even if it is cold.

If I am hunting hot weather and will have cool or colder water available such as a spring, I will take clear 4 or 6 mil large bags with me. Put quarters or boned out meat, build a small dam, get them cooled very well. Goat 2 years ago was at 70 deg and sunny. Over night the meat was at 36 deg and dry, zero flies. Tie the top up, run paracord to an anchor to hold the top up out of the water.


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[Bulldawg]

Larry that is some really good information. Makes me want to start doing the same things in the lower 48 where our lows may be very similar but the highs are much higher. It really surprised me how long it took to get cool. I thought it would be faster than that but I guess that all that makes sense.


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[Larry Bartlett]

Sometimes science is hard to believe, Bulldawg. But when you can replicate the tests and produce reliable outcomes...theory becomes proven and fieldcraft is strengthened.

I'd be proud to see similar graphs made in warmer climates. It'll make us all smarter.

later fellas

 

[Kevin Dill]

I don't know about anyone else but the attachments don't work for me.

 

[Beendare]

Checking meat temp in the field....LB you are my Idol! /grin

I can only add anecdotal evidence. Boned out elk meat shot in temps as high as 65-70 deg [night time temp of 35 deg or less] at elevations above 8k, boned immediately and hung or racked in the shade with good cool air flow is always cold through and through the next morning and it will stay that way and be fine for a few days anyway....though I wouldn't want to chance that for more than a few days.

 

[bbell]

Saw this and wanted to bring it back up. I have always wondered how cool is cool enough. For instance my family has hunted eastern Oregon for years. During deer season it can be 80’s and I am sure even 90’s. Nights range from 20’s-40’s depending on the year. My family packs in on horses and it takes two days till we get back to town when we are done. There have been many times where a buck was shot opening day but they hunted another 4 days or so to fill another tag. The meat is hung at night and then during the day stuffed under a bush covered with packing tarps(canvas). Never have they boned out a quarter. Then to think of it the meat never got put in a cooler on the way home. It stayed in the bags and covered with tarps for the 8 hr drive home. Then we cut it ourselves. They have never had one deer go bad on them. I always thought it was normal till the internet and reading about everyone else.

How did they not lose the meat? My guess is the dry climate put a crust on the meat that protected it. The crust was always thick, but always beautiful good meat underneath. Any thoughts?

 

[jwooley]

Depends on time of year.. Here in Colorado in mid November it averages 40s in the day to 20s at night.. with those temps it will take probably 24 hours for the meat to get to a steady temp.. With those temps meat hanging in a closed building meat stays around 37.. keeping it from 32f to 40f is key..

 

[Larry Bartlett]

If the nights are 20s and days are 80s, the average storage temperature will be close to 45-49 degrees F deep tissue by day 4. A homeostasis with meat and climate is reached around 48 hours post harvest and balances out almost entirely based on average temperature and humidity by day 4 post harvest. This transitory state is marked by a lot of cellular activity and unstable spoilage threats. Its often day 4 or 5 before hunters starts noticing changes with meat toward the bad side of the scale.

This might help explain why they never lost meat. The key being home and cared for by day 5-ish post harvest.

 

[BornBowHunter]

Anyone know the laws of thermodynamics as they apply to cooling rates for game meat?

I'd like to share what I know because i think it's helpful, but would like to learn what hunters south of Alaska observe with game meat cooling rates in warmer environments.

larry

Larry, new to rokslide. This was my first read and wow am I impressed. You did what most of us wonder but never do!

Question, did you leave the quarters intact when taking your temperature readings? Did you release any internal bone heat by opening up the meat on the quarter?


Thanks for the hard work