The Knowledge Behind Aging Meat

Kjell Hedstrom 2017

 Dalarna, Sweden.   Moose cow and calf hanging and dry aging while waiting for the final day of the annual moose hunt. Depending on hunting schedule and ambient temperature it is not uncommon that hunters have to butcher the dry aging moose prematurely. Savvy hunters then switch to wet aging the processed meat cuts to reach at least the minimum 40  °   C day grades before freezing the meat. 

Dalarna, Sweden. 

Moose cow and calf hanging and dry aging while waiting for the final day of the annual moose hunt. Depending on hunting schedule and ambient temperature it is not uncommon that hunters have to butcher the dry aging moose prematurely. Savvy hunters then switch to wet aging the processed meat cuts to reach at least the minimum 40° C day grades before freezing the meat. 

 

Does aging meat even make sense?

Some common questions, objections and comments I hear when the subject of aging meat comes up are: 

  • I don’t age deer and it tastes amazing.
  • My deer is tender enough.
  • Why age it? It will taste the same no matter what.
  • After soaking it in Italian dressing for 24h it will taste amazing
  • Backstraps don't need aging. The rest I grind into sausage. 
  • Why the hell should I age my venison?
  • You can't age venison. It doesn't have enough fat.

Deer tastes amazing. period. It is possible to screw things up but unless you mishandle the meat the chance is that your recently killed doe or buck will be a treat. So why even think about aging it?

Aging makes venison very tender. The difference is not a little. The difference is huge. Aging reduces the gaminess and significantly adds and improves the flavor.  My question to you is instead:
Why should you not age your venison?

If you have never aged venison before then please try it - if nothing else, try one muscle cut and age it. It's not hard. You don't need to take a risk with dry aging it. Just vacuum pack it, put it in the fridge and follow the advice in this blog. You will get steak that has improved greatly compared to being prematurely frozen.  The chance is high that you just started down the path to significantly expand your recipe selection, improve your steaks to roast ratio and boost your future venison taste experience.
 

What Aging Meat is All About

When aging meat the meat becomes more tender. The tenderization starts to happen after rigor mortis when the PH drops and activates natural enzymes in the muscle tissue. When this happens the meat, using its own enzymes is breaking down the proteins in cells and binding tissue - the collagen. The aging makes meat  more flavorful, more tender, less tough, easier to cut and chew.  The following factors have a huge impact on how tender the meat is:

 The result after a successful moose hunt in Sweden.  Several moose are dry aging in the village big game processing house.

The result after a successful moose hunt in Sweden.  Several moose are dry aging in the village big game processing house.

  1. how contracted the muscles are 
  2. amount of binding muscle tissue  - collagen
  3. fat marbling

Short tenderization time makes different animals (young, old, different species) differ in tenderization. Longer tenderization time reduces or completely removes the difference in tenderization. 

A correctly tenderized old buck can be made as tender as a fawn. With aging the flavor of the meat changes - meat that is not aged is lacking flavor compared to aged meat. Meat that is cooked up immediately after the kill is far below the flavor of an aged cut of meat.

For beef the fat marbling helps the tenderization - lean wild game can become just as tender with the right approach even if the fat marbling factor is not there to boost the process.  I have no experience with aging beef but my understanding is that for dry aging the fat marbling helps the meat from becoming too dry - for that reason there are rarely advice on dry aging wild game for more than 2 weeks. 

 

Types of Aging

The most common type of aging in the beef industry is wet aging, a.k.a. vacuum aging. It's cheap, dead simple to get it right and generates excellent result.

The most well known method of aging meat among hunters is dry aging. It is well known that the more expensive dry aging method will produce the best quality meat, at least slightly better than the result from wet aging. The main disadvantage with dry aging is that it requires more from the locale in terms of space and controlled temperature and that there will be more waste.

Regardless of wet aging or dry aging, the end result can vary greatly depending on how long the meat is aged. This blog aims to give you knowledge about how long the meat should age and how to get the same, great tenderized meat, every time, in spite of temperature variations.  

 

Aging Advice From The Experts

It turns out that most advice for aging meat is not given in specifics - it's a range of  days and temperatures. Unless you know the relationship between tenderization, temperature and time you can easily fail to produce the tender and flavorful meat you are striving for. 

What we really want is a system to measure the aging process and to get the same, excellent result, every time.  Aging meat should be done in cool temperatures to avoid spoilage by bacteria. With that in mind, the breaking down of collagen - i.e. the tenderization process, will be more rapid in higher temperatures. When we age an animal we would ideally like to get the same great result every time, regardless of temperature variations.  It turns out that such a system to measure the aging process already exists and is used by hundreds of thousands of well educated hunters - in Scandinavia. It is time we start using this system also in the USA. 

In Enters the °C Day Grade Measurement System

  • So, what is this Celsius° day grade measurement system?
  • How can you know that it makes sense? 
  • Why using a Celsius° system when Fahrenheit° exists?
  • Why haven't I heard about the "Day Grade" system before?


This blog will try to answer these questions and make some comparisons between advice I have found from American experts on hunting and meat processing. This blog will give you knowledge on how long, temperature dependent, aging you should give your next deer or elk.

It is the purpose of this article to give you the information needed to age your meat the manual way, or through the  foolproof process using our tenderization timer

So, what is this Celsius° day grade measurement system?

 Quarters, backstrap and some of the finished vacuum packed result - ready to go into the fridge for at least the minimum 40 °  C day grades.

Quarters, backstrap and some of the finished vacuum packed result - ready to go into the fridge for at least the minimum 40° C day grades.

The formula is simple, within a span of reasonable temperatures,  the aging of meat follows a similar pattern that can be explained as follows:

  1. The average Celsius temperature for the day is called the day grade
     
  2. When the cool, average  ambient temperature has reached 40°C day grades the meat has aged its minimum time. Since we should only age meat in cool temperatures reaching 40°C day grades will take some time.  
     
  3. 40°C day grades is considered the generic minimum  - and please keep in mind that older animals can benefit from longer age time. Younger animals do not need as much aging time but it will not hurt either. Some small game like jackrabbit, rabbit and squirrels benefit from longer aging time.
     
  4. The rate of tenderization decreases rapidly after 40°C day grades, i.e. 80°C day grades does not mean the meat is twice as tender as 40°C day grades.
     
  5. 60°C day grades is my personal preference
     
  6. Meat should be aged at low, preferably fridge cool, temperatures. My recommendation is to keep the meat aging  between average temperatures of:  37°F41°F (2.8°C  -  5°C)

    Under the right conditions with a carcass that is not contaminated and with a well cleaned gun/arrow penetration area it is not uncommon to dry age meat in 45 - 50°F  i.e. 7° C - 10° C
     
  7. Example of average day temperatures to reach 40°C  day grades. 
  • 50°F   equals 10°C.   40/10 = 4 --->  4 days. 
  • 38°F equals 3.3°C.    40/3.3 = 12 ---> 12 days
 Relationship between temperature and time to reach the minimum of 40  °  C day grades. 

Relationship between temperature and time to reach the minimum of 40°C day grades. 

Tenderum-US-portable1.jpg

Recommendation:   Unless the meat is in a well controlled environment the temperature will fluctuate.

If the animal is dry aging in a barn or in a garage you can count on big temperature variations during 24h. Even in a fridge there will be temperature variations.

I strongly recommend that you try out our tenderization timer. The small, energy efficient and robust timer measures the ambient temperature every 21 seconds and calculates the average day grade temperature. The timer is the best way of getting the same tenderized result from one animal to another, year after year. 

Why using the Celsius Day Grade System? Why not Fahrenheit?
The timer and manual calculation in the day grade system both use the Celsius Day Grade calculation. I am sure you could create a Fahrenheit system but with the proven Celsius Day Grade system, why bother?

Q: Why using a Celsius° system when Fahrenheit° exists?
Example of the difficulty with Fahrenheit to measure aging: 
40°F equals 4.4°C which gives 9 days to reach the 40°C day grades.  
50°F equals 10°C which gives 4 days to reach 40°C day grades.  
60°F equals 15.6°C which gives 2.5 days to reach 40°C day grades.  

The Fahrenheit grade system does not give a linear solution and is thus hard to reason about. For meat aging it is better to keep to the Celsius day grade system - it will give the same result regardless of temperature variations. 

HUNTING AND WILD GAME experts WITH AGING RECOMMENDATIONS

Q: How can you know that it makes sense? 
Below are 5 examples of different aging advice from some very knowledgeable people. Let us see how their advice are on the day grade measurement scale compared to my recommended minimum aging time.  My recommended aging day grades are 40°C as a minimum but my preferred, well aged, value is 60°C day grades.  With this comparison I hope to show you that the minimum of 40°C day grades makes sense. 

Values are rounded. 

Cabela's Hunters Harvest, 2017:     
Age in 34°F - 37°F for 7 - 21 days.

Days of Aging Day °C Grades Compared to 40°C Day Grades
34°F 1.1°C Days: 7-21 8 - 23 C° Ranging from: barely aged to slightly more than 50%
37°F 2.8°C Days: 7-21 19 - 59 C° From roughly 50% to well aged. 14 days are enough to reach the minimum

 

Rocky Mountain Elk Foundation (recommended read):  
Age above freezing and below 40°F - deer 10 days, elk 14 days.

Note: The upper range is used in the table. As seen from the Cabela's table above the cooler temperatures requires more than 10 or 14 days. 

Temperature Days of Aging Day °C Grades Compared to 40°C Day Grades
40°F : 4.4°C Days: 10 44 C° Deer: Minimum aging reached!
40°F : 4.4°C Days: 14 62 C° Elk: Spot on. 60 C° day grades is my preferred value for day grades

 

North Dakota State University [NDSU article,  easy read pdf]: 
Age in 34°F - 37°F for 10 - 14 days. Sufficient with  2-3 days.  Fairly similar to Cabela's advice. 

Days of Aging Day °C Grades Compared to 40°C Day Grades
37°F 2.8°C Days: 2-3 6-8 Barely aged
34°F 1.1°C Days: 10-14 11-15 Barely aged
37°F 2.8°C Days: 10-14 28-39 From roughly 50% to just below minimum

Opinion: Disappointingly low aging is recommended by NDSU. Maybe they should do a taste test ?


Hunter - Angler - Gardener - Cook : Hank Shaw on aging pheasant and wild game
After analyzing research papers and with his own experience Shaw recommends:
50°F - 55°F for 3 - 7 days    

Temperature Days of Aging Day °C Grades Compared to 40°C Day Grades
50°F : 10°C Days:3 30 C°dg 75% of minimum aging is reached
50°F :10°C Days:7 70 C°dg Well aged. 70 day grades is close to my own preferred day grade goal
55°F:12.8°C Days:3 38 C°dg Just short of the recommended minimum.
55°F:12.8°C Days:7 89 C°dg Well aged. Over the double of the recommended minimum

Hank Shaw is within the range of reasonable day grades worth of aging. The danger here is the fairly high temperature. The meat and the aging environment must be impeccable to avoid spoilage by bacteria. It is safer to age in cooler temperatures for longer time.

The focus on Shaw's article was on pheasants and not big game. Regardless, it it safer to age your big game, small game, pheasants or other game birds at a lower temperature.

AmericanHunter.org: How to Age Venison ... 
40°F for 7 days - but up to 17 days.             

Temperature Days of Aging Day °C Grades Compared to 40°C Day Grades
40°F : 4.4°C Days: 7 31 C° 78% of minimum aging is reached
40°F : 4.4°C Days: 17 76 C° Well aged. 75 day grades is almost double the minimum.

 Well aged and slightly high temperature. The meat and the aging environment must be impeccable to avoid bacterial destruction. 
 

I tried googling for "40° C Day grades system" ....

 Mule deer venison vacuum aging until 60  °   C day grades

Mule deer venison vacuum aging until 60° C day grades

Q: Why haven't I heard about the "Day Grade" system before?

If you did a google search on the topic, the likelihood is that you did not find anything for Celsius Day Grade system - except maybe the blogs on JagareLtd. The reason is simple. The 40° C Day Grades system is used in Scandinavia. These hunters, chefs, butchers etc that blog and write about it use Norwegian, Danish and Swedish.  If you instead search for "40 dygnsgrader" (Swedish) you would get a couple of thousand hits. 

Below I have collected some Swedish and American articles on aging and closely related topics that I think are worth reading.  The Swedish ones also come with a Google Translate link. In case the translation stops working you can always put in the URL for the Swedish article into Google Translate to get an updated translation. 

American Resources
 

  1. Field and Stream: Deer Hang Time 
     
  2. American Hunter: How to Age and Braise Venison by Georgia Pellegrini
     
  3. Hunter Angler Gardener Cook : On Hanging Pheasants by Hank Shaw
     
  4. Rocky Mountain Elk Foundation: Dry Aging Timeline  by John McGannon
     
  5. Deer Recipes Online - How to Age Venison and Why you Should
    (To my knowledge on of the advice, "wet aging after freezing" might not work or is not as effective as aging before freezing)
     
  6. RealTree: 12 Reasons Why Your Venison Tastes like Hell 
     
  7. Legendary Whitetails: How to Age Venison at Home
     
  8. Research sources:
    Texas Agriculture & Life Sciences University: Meat Science. Class study material but quite informative:
    Conversion of Muscle to Meat 
    Meat Tenderization
     
  9. Beef Quality Research: The phases of Rigor Mortis explained (2 min video)
     
  10. Meat and meat products in human nutrition in developing countries (very informative)
    meat quality
     
  11. RealTree: The great debate: Aging Venison
     
  12. Outdoor News: Chef Eileen Clark - Tips for Aging 
     
  13. Omaha.com - Article on aging game birds
     
  14. Washington Department for Fish & Wildlife: General advice on meat processing - from field dressing to aging and freezing it. 
     
  15. The Science of Meat Tenderizer : How do Enzymes work
    Discovery Express Kids - Made for kids and with a kick-ass clarity to the text. 

 

 

Swedish Resources

The Google translation is so-so. Hopefully it will make some sense :) 

  1. Swedish Wikipedia:  Tenderization
    Recommended minimum 40°C day grades [translated]
     
  2. Svensk Jakt: Let the Meat Age 
    Swedish Hunter magazine -  recommended 40°C to 60 day°C grades [translated]
     
  3. Svenska Jägareförbundets : 60°C day grades
    Swedish Hunter's Association - recommended 60°C day grades [translated - but lost formatting]
     
  4. Självhushållnings Handbok: How to butcher 
    Subsistence, DIY wiki handbook - recommended 40°C day grades [translated]
     
  5. Svenska Jägareförbundets : How You Create Tender Meat
    Swedish Hunter's association. Interview with Mikael Löf from DeVilda Wild Game Processing - with over 1,000 wild game processed annually - recommended 40°C day grades, more if conditions are met [translated]
     
  6. Skogssällskapet: Good Hygiene and Dry Aging - that's when you get the best meat
    The Swedish Forest Society Foundation - recommended 40 -  60°C day grades [translated]

 

 

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