An animal has been processed. But the beef isn't ready yet. In fact, during the next 24 hours, something remarkable is happening inside the muscle.
The heart has stopped.
Blood circulation has stopped.
Oxygen is no longer being delivered to the muscles.
But inside those muscle cells?
The chemistry hasn't stopped yet.
Stored energy is still being used.
Muscle pH is changing.
Proteins are changing.
The carcass is cooling.
Rigor mortis is developing.
And natural enzyme systems are beginning processes that will continue long after the first day is over.
This is the beginning of one of the biggest transformations in beef:
Muscle becoming meat.
And a surprising amount of what eventually determines the characteristics of that beef is already being set in motion during those first 24 hours.
AT FIRST, IT'S STILL MUSCLE
This seems obvious.
But think about what living muscle actually does.
It contracts.
It relaxes.
It uses oxygen.
It receives nutrients through circulating blood.
And it continually produces and uses energy.
One of the most important molecules involved is:
ATP.
Adenosine triphosphate.
Think of ATP as usable cellular energy.
Living muscles need it to contract.
But here's the really important part:
They also need ATP to relax.
After processing, circulation stops.
No more oxygen is being delivered.
No more nutrients are arriving.
But the muscle doesn't instantly run out of energy.
It still has some fuel left.
THE MUSCLE STARTS BURNING THROUGH ITS RESERVES
One of those reserves is:
Glycogen.
Glycogen is stored carbohydrate in the muscle.
While the animal is alive, it serves as an energy reserve.
After processing, the muscle can still use that glycogen to generate energy for a period of time.
But now there's a major difference.
There is no circulating oxygen supply.
So muscle metabolism continues under anaerobic conditions.
As glycogen is metabolized after death, lactate accumulates.
And that changes something enormously important:
pH.
THE pH STARTS FALLING
Living muscle is relatively close to neutral pH.
Beef Research describes normal muscle as beginning around a pH of approximately:
7.0.
During normal postmortem metabolism, lactate accumulates and the pH falls.
Normal beef ultimately reaches approximately:
5.4 to 5.7.
That's a substantial chemical change.
And it isn't just some number meat scientists like measuring.
The rate and extent of that pH decline can affect meat quality.
Color.
Water-holding capacity.
Protein behavior.
Tenderness.
Shelf life.
All can be influenced by what happens with pH after processing.
MEANWHILE, THE CARCASS IS COOLING
While all of that chemistry is happening inside the muscle, something much easier to see is happening outside it.
The carcass is being chilled.
That's obviously important for food safety and preservation.
But chilling isn't simply a race to make the carcass as cold as physically possible.
Because muscle temperature and muscle chemistry are changing at the same time.
And those two processes interact.
Beef Research identifies both muscle temperature and pH at the onset of rigor, along with the rates at which temperature and pH decline, as factors affecting beef tenderness.
In other words:
Cooling matters.
pH matters.
And:
When each one happens matters.
AND THEN THE MUSCLE STARTS TO LOCK
Remember ATP?
The energy molecule that helps muscles contract and relax?
The muscle's ability to continue generating ATP doesn't last forever.
Eventually those energy reserves are depleted.
And when sufficient ATP is no longer available, the molecular machinery responsible for muscle contraction can no longer cycle normally.
The muscle stiffens.
This is:
Rigor mortis.
It's not something happening to the beef from the outside.
It's a consequence of the chemistry occurring inside the muscle after death.
Muscle that was once capable of contracting and relaxing eventually becomes fixed in the rigor state.
SO YES, FRESHLY PROCESSED BEEF ACTUALLY GETS TOUGHER FIRST
This is one of the most interesting parts of the entire story.
Because most people assume:
Animal processed → beef → tender steak.
Not exactly.
As rigor develops, the muscles stiffen.
Older Oklahoma State meat-science research describes muscle immediately after rigor as relatively tough and notes that many characteristics affecting the desirability of meat are established during the first 24 to 48 hours after death.
Which means the path toward a tender steak initially goes in what sounds like the wrong direction.
The muscle stiffens.
Then something else starts happening.
THE BEEF HAS ITS OWN TENDERIZING SYSTEM
This is where our previous Beef Report about 14-day aging connects.
Muscle contains naturally occurring enzymes.
One particularly important enzyme system involves:
Calpains.
After processing, these enzymes can begin breaking down specific structural proteins within muscle.
They aren't dissolving the steak.
They aren't destroying all the connective tissue.
Instead, postmortem proteolysis changes structural components within the muscle.
And those changes contribute to increasing tenderness as beef ages.
SDSU explains that calpain remains active after harvest and degrades proteins in ways that improve tenderness. Beef Research similarly describes refrigerated postmortem aging as allowing natural enzymatic and biochemical processes to improve beef tenderness.
And here's what's really interesting:
That process doesn't wait until Day 7.
Research examining individual beef muscles has found evidence of calpain activation and meaningful proteolysis already occurring at:
24 hours postmortem.
The aging process is already underway.
BUT 24 HOURS DOESN'T MEAN THE BEEF IS DONE AGING
Not even close.
This is where we have to separate two processes that overlap.
Rigor mortis is developing during the early postmortem period.
Aging involves biochemical and enzymatic changes that continue for days afterward.
The first day sets a lot in motion.
But tenderness continues improving well beyond it.
Beef Research has found increasing tenderness with additional postmortem aging, and different muscles respond at different rates. Some muscles require around the standard 14-day aging period, while others may benefit from longer aging.
That's why our beef doesn't go from processing straight to the cutting table.
At Falula Farm:
We wait 14 days.
The first 24 hours begin the transformation.
The following days give that transformation time to continue.
AND THIS IS WHY TEMPERATURE MATTERS SO MUCH
Here's another surprising part.
If muscle gets too cold too quickly while it's still pre-rigor, something called:
Cold shortening
can occur.
Muscle fibers can contract excessively.
And that can make beef tougher.
The American Meat Science Association describes cold shortening as an important pre-rigor phenomenon capable of producing substantial toughening.
But that doesn't mean:
Slow cooling = automatically better beef.
Food safety still requires controlled refrigeration.
And excessively warm postmortem conditions create their own problems.
This is a balancing act between:
Temperature.
Time.
pH.
Muscle biology.
And food safety.
Which is why proper carcass chilling is a real processing step, not simply:
Put the cow in a cooler.
DIFFERENT MUSCLES DON'T EVEN COOL THE SAME WAY
A beef carcass is big.
And it's not uniform.
Some muscles are deeper inside.
Others are closer to the surface.
Some are insulated differently by fat and surrounding tissue.
Researchers monitoring beef carcasses during the first 24 hours have measured significantly different cooling rates even between the inside and outside portions of muscles in the round.
Think about that.
Same animal.
Same cooler.
Same 24 hours.
Different muscle temperatures.
The chemistry happening inside a Ribeye isn't necessarily progressing at exactly the same rate as the chemistry happening deep inside another muscle.
Beef is complicated.
And that's what makes this so interesting.
THIS ALSO EXPLAINS SOMETHING ABOUT COLOR
Remember our Beef Report:
Too Red to Be True?
Color is tied into this chemistry too.
Myoglobin gives beef much of its characteristic color.
But postmortem pH, oxygen exposure, temperature and the chemical state of myoglobin all influence what color we eventually see.
That's why beef can appear:
Purplish.
Deep burgundy.
Cherry red.
Brown.
And those colors don't simply translate into:
Fresh.
Not fresh.
The biochemical story is much more complicated than that.
The first day after processing is already helping establish the environment in which those later color reactions will occur.
AND THIS IS WHERE THE ANIMAL'S LIFE BEFORE PROCESSING CAN FOLLOW IT INTO THE COOLER
This is the part that deserves its own Beef Report.
But we can't talk about the first 24 hours without mentioning it.
Remember that muscle glycogen we talked about?
The fuel being converted after processing?
How much glycogen is available at the beginning matters.
Significant or prolonged stress before harvest can deplete muscle glycogen.
If too little glycogen remains, there may not be enough postmortem lactate production for the muscle to reach the normal ultimate pH.
That can result in:
Dark cutting beef.
Also known as dark, firm and dry beef, or DFD.
Beef Research identifies potential contributing stressors including transport exhaustion, fear, climatic stress, prolonged feed withdrawal, mixing unfamiliar animals and extreme excitement.
So what happens before processing and what happens afterward aren't two completely separate stories.
They're connected through biology.
And we're going to give that connection its own article.
SO WHEN DOES MUSCLE ACTUALLY BECOME MEAT?
There isn't a magical second when somebody flips a switch.
That's what makes the question so interesting.
The transformation is a process.
Circulation stops.
Oxygen disappears.
Stored glycogen continues supplying energy.
Lactate accumulates.
pH falls.
ATP becomes depleted.
Rigor develops.
The carcass cools.
Proteins change.
Enzymes begin modifying muscle structure.
And gradually the biological system that once powered movement becomes the food we recognize as beef.
Muscle doesn't simply stop being muscle.
It changes into meat.
HERE'S WHAT WE'RE QUESTIONING
Why do we talk so much about what happens to beef in the kitchen...
and so little about what happened before it ever became a steak?
We debate:
Rare or medium?
Reverse sear or grill?
Salt before or after?
Rest five minutes or ten?
All useful questions.
But some incredibly important events happened long before you turned on the stove.
The animal's muscle chemistry changed.
The carcass went through rigor.
Temperature fell.
pH fell.
Natural enzymes went to work.
And those processes helped create the piece of beef sitting on your cutting board.
Cooking isn't the beginning of the steak's story.
Not even close.
AND THIS IS WHY WE DON'T RUSH OUR BEEF
At Falula Farm, processing isn't the end of the job.
It's the beginning of another stage.
The carcass needs to chill.
Rigor needs to develop.
The normal postmortem chemistry needs to happen.
And then:
We age our beef for 14 days.
During that aging period, natural enzymatic processes continue changing the muscle proteins and improving tenderness.
Only after that aging period do we move into the next steps of turning the carcass into the cuts our customers receive.
Steaks.
Roasts.
Specialty cuts.
Ground beef.
Vacuum sealed.
Labeled.
Frozen.
The wait isn't dead time.
The wait is part of processing the beef.
THE BEEF REPORT BOTTOM LINE
The first 24 hours after an animal is processed aren't quiet.
Biologically?
A lot is happening.
Muscle glycogen is being metabolized.
Lactate is accumulating.
pH is falling.
ATP is disappearing.
Rigor mortis is developing.
The carcass is cooling.
Natural enzymes are already beginning processes associated with tenderization.
And the balance among temperature, pH and time can influence the characteristics of the beef that eventually reaches your plate.
The animal has been processed.
But the beef isn't finished.
Not even close.
For us, there are still 14 days to go.
And during every one of them:
The beef is changing.
That's why we wait.