Basic Meat Science For Outdoor Cooks

"My foe, my enemy, is an animal. In order to conquer him I have to think like an animal and, whenever possible, to look like one. I've got to get inside this dude's pelt." Carl Spakler (Bill Murray) in Caddyshack, 1980

By Meathead

As meat is heated, it undergoes physical and chemical changes called denaturing, and as scientific as this process is, it is also magic. It is a complex process, but a basic understanding is the first step in making an omnivore's delight.

What is meat?

Meat is cut from the muscles of mammals and birds. For some reason, fish muscle is not considered meat by some people, but it should be.

Lean muscle tissue typically breaks down like this: Water (about 75%), protein (20%), fats (5%), carbohydrates (1%), and vitamins, sugars, and minerals (1%).

Animal	% Water	% Protein	% Fats	% Other
Beef	72	21	6	1
Pork	69	20	10	1
Chicken	73	21	5	1
Lamb	73	20	5	2
Cod	81	17	1	1
Salmon	64	21	14	1

Different cuts can differ significantly. Shoulder meat tends to have a lot more fat and connective tissue. Pork rib meat, for example, is more like 65% water, 18% protein, 15% fat, and 2% vitamins, sugars, and minerals.

With that much water in the meat, any loss you might have from stabbing it with a thermometer or an occasional stab with a fork is minor, so don't let the snobs tell you that you are going to ruin the meat if you use a thermometer.

Muscle cells. Muscle cells are about the thickness of a human hair and are surrounded by a sheath of thin diaphanous connective tissue that attaches the cells to each other to form bundles called muscle fibers and bundles of bundles called myofibrils. Muscle cells are mostly protein and water. The proteins are mostly myosin and actin, which react differently to heat. As an animal ages, grows, and exercises, muscle fibers get thicker and tougher. So do the connective tissues.

Connective tissues. Connective tissue is most obvious in the form of ligaments that connect muscles to bones. It is also visible as the thin shiny sheathing that wraps around muscles called silverskin. These tougher, chewier connective tissues are appropriately named elastin. A softer connective tissue called collagen is invisibly scattered throughout the muscle, often surrounding fibers and sheaths. When you cook, collagen melts and turns to a rich liquid called gelatin, the same stuff Jell-O is made from. The muscle fibers, no longer bound together by collagen, are now uniformly coated with a soft, gelatinous lubricant. This gives meat a wonderful silky texture and adds moisture.

Lean meats like beef or pork loin and tenderloin, as well as most chicken and turkey, don't have much collagen. When cooking tough cuts of meat with lots of connective tissue, like beef or pork ribs, brisket, and shoulder, it is important to liquefy connective tissue into gelatin. This takes time. After it melts, as it chills, gelatin can solidify into that jiggly stuff which, with a little processing, can then be called aspic and served at bridge clubs. Here's a pot of the stuff made simply by boiling a couple of chicken carcasses cleaned of meat and then chilled.

Fat. Fat is the fuel that powers muscles. It is packed with calories. It comes in three types: Subcutaneous fats are the thick hard layers beneath the skin. Intermuscular fats are layers between muscle groups. Intramuscular fats woven amongst the muscle fibers add moisture, texture, and flavor to cooked meat. These threads of fat are called marbling because they have a striated look similar to marble.

Fat is crucial to meat texture. Waxy when it is cold, at about 130°F to 140°F fat starts to melt and lubricate the muscle fibers just as they are getting tougher and drier under the heat. Fat does not evaporate when you are cooking as does water.

Fat is also the source of much of the flavor in meat. It absorbs and stores many of the aromatic compounds in the animal's food. As the animal ages the flavor compounds build up and get stronger. After the animal is slaughtered, the fat can turn rancid if stored too warm, too long, or in contact with oxygen. So we have a tradeoff. The muscle fibers and connective tissues get tougher as the animal ages and exercises, while the fat accumulates and builds flavor.

Fats, especially animal fats are the subject of a great deal of debate among scientists, doctors, dietitians, and health faddists. For many years they were thought to be dangerous and to be avoided. It is now thought that fats, even animal fats, contain many beneficial properties, and some argue that, in moderation, they are essential for health. A great deal of interesting research on the subject is going on as I type this. A great deal of research is contradictory. I am not a doctor, but I read a lot about food and diet, even technical research. My conclusion: No food is dangerous in moderation. No food is magically healthy.

Fluids. Most of the liquid in meat is protein laden water called myoglobin. The reddish color in meat and its juices is not caused by blood. It is myoglobin. Myoglobin is found only in muscle, not in the blood stream. The blood was pretty much all drained out in the slaughter house. If the stuff on your plate when you slice a steak was blood, it would be much darker, and it would coagulate, like human blood. If the fluids were blood, then pork and chicken would be dark red. It's mostly just water, so let's stop grossing out our kids, and just call it juice. OK?

Slow twitch vs. fast twitch muscles

Muscle fibers need fat and oxygen for fuel. Fat comes from fatty acids in the animal's blood that were created by digestion of its food. Oxygen is carried by the protein hemoglobin in the blood stream and it hands the oxygen to myoglobin, within the muscles.

In general, the more exercise a muscle gets, the tougher it is, and the more oxygen laden myoglobin it needs. Myoglobin turns meat darker and makes it more flavorful. Dark meats, like chicken thighs are made of "slow twitch" muscles designed for slow steady movement and endurance, and are loaded with juicy myoglobin. White meats, like chicken breasts, are mostly "fast twitch" muscles, designed for brief bursts of energy, and have less myoglobin. Dark meats also have more fat for energy.

When cooked, slow twitch muscles have more moisture and fat and are more flavorful than white meat. White meats contains less moisture and fat, and so it dries out more easily when cooking. The legs and thighs of chickens and turkeys get more exercise standing and walking, so they have lots of slow-twitch muscles, more pigment, more juice, more fat, and more flavor. They are also slightly more forgiving when being cooked. Modern chickens and turkeys have been bred for large breasts because white meat is more popular in this country (and I for one, can't understand why).

Ducks and geese are designed for flying and swimming and they get more exercise than chickens and turkeys, so they have more dark meat. Duck breasts are deep purple, almost the same color as lamb or beef.

Modern domestic pigs have been bred to have less intra-muscular fat for a health fad conscious society, and they don't get much exercise, so they have become "the other white meat".

Beef is all pretty much the same color, but slow twitch muscles like flank steak have bigger richer flavor.

Fish live in a practically weightless environment, so their muscles are very different, with very little connective tissue. That's one of the reasons why fish never gets tough. But it can dry out because there is not much collagen to moisturize the fibers. The color and texture of fish varies depending on the life it leads. Small fish swim with quick darting motions have mostly fast-twitch muscles and white meat, and flounder, which lives on the bottom, has delicate flaky flesh. Torpedos like tuna and swordfish swim long distances with slow steady tail movements so they have have firmer, darker, sometimes even red flesh. For these reasons, and others, fish can spoil within days of being caught while red meats keep much longer.

Buying meat

Lean in and I'll tell you the most important secret to eating well: Get to know your butcher.

In my book, knowing a good butcher is more important than knowing a good stock broker. That's my favorite butcher at right wearing an AmazingRibs.com cap, Dario Cecchini in his 200-year-old butcher shop in Panzano-in-Chianti in Italy. OK, I don't see him often, but I do know the head butchers at all three groceries near me, and they know me, too.

In my blue-collar neighborhood in a suburb just west of Chicago there used to be many butcher shops. The big grocery stores and the big department stores that carry meat, like Walmart, have put them all out of business. In the past decade I have lost two great butcher/craftsmen to the big box stores, Hermann Zanoni and Dennis Morini.

Many grocery stores get their meat shipped to them pre-cut and packaged from a central warehouse. But some still have butchers on premise. Find them. The head butcher is usually on duty early morning through early afternoon. Stop at the counter and ask for the head butcher or the assistant. Don't be surprised if they are women. Introduce yourself. Chat them up. Swap recipes. Tell them about AmazingRibs.com. Get the direct phone number of the butcher department. Ask them about their favorite cuts and what they think are some of the best meats they get. Ask if they can special order USDA Prime grade beef or less popular cuts like beef tri-tip or whole packer briskets. Set yourself apart from the crowd.

Many big grocers get fresh meat every day, but some don't. Ask about delivery dates and times. Unless you're on the coast, fish is usually not delivered daily and freshness is more important in fish than any other meat.

One day, bring in a slab of ribs you're proud of and leave it for the butcher staff to enjoy with lunch. Show them you've got the chops and they'll get you the best chops.

Soon after you meet them, while they can still taste those ribs, call in an order. Normally they don't cut ribeyes 1 1/2" thick, and I think that's the best size, so order some. Ask the to look for "top choice". That's the best grade of USDA choice, usually the best in the house. Most groceries don't stock USDA prime grade. Click here to learn more about beef grades. Don't be in a hurry and be willing to pay full price for the best cuts although my butcher has been known to set aside the pick of the litter for me even when it is on sale.

Despite the disappearance of the small family butcher shop, some new ones have sprung up in ethnic neighborhoods. Kosher and halal diets require special butchering techniques, so in Jewish and Middle Eastern neighborhoods you can still find real butchers who will custom cut for you. African and Mexican cooking calls for cuts not normally found in the supermarkets, so these neighborhoods also have real artisans on hand, not to mention wonderful exotic ingredients to broaden your horizons.

Not all meat is the same. Get to know your meat cuts and grades but don't be afraid to ask your butcher for help. Baby backs cost more than spare ribs, but spare ribs are usually richer and juicier because they have more marbling and more connective tissue. But baby backs have better marketing (remember the Chili's jingle?). Filet mignon is the most tender beef cut, but ribeye is more flavorful. I've written articles on the different cuts of beef and the different cuts of pork.

Pick meat carefully. Don't just grab anything. Linger over the meat counter and concentrate. Look at the evenness of the cut. If one end is thinner it will overcook. Look at the exterior fat. You'll want to remove most of it, so find cuts with the least waste. Look at the marbling.

Open display cases work fine, but the bottom pieces may be cooler than the top pieces. Compare the different packages. Look for liquid in the package. This is called purge and is often a sign that the meat has been frozen and thawed. This moisture and flavor cannot be replaced. Avoid meat with a lot of purge.

Pay attention to the dates on packaging. "Sell By" date tells the store when to remove products from the shelf. "Best If Used By" or "Use By" dates tell you when you should eat or freeze the product. These dates are not related to safety, just quality. And you can no longer rely on the color of meat if it is prepackaged because some grocers now sell red meat packed in a carbon monoxide atmosphere to prevent browning. Remember, the dates are meaningless once the package has been opened and exposed to air and bacteria.

There are a few days right after slaughter when rigor mortis makes the meat tough, but that is gone by the time the meat arrives in your store. As meat ages, enzymes and oxidation change the flavor. Pick the most recently cut meats. Yes, beef can improve with aging, but it has to be aged properly. Beef seems to be best after about 28 days if it is packed in Cryovac, that thick vacuum sealed plastic. It will not keep that long if it is just shrink wrapped onto a styrofoam tray with air inside. Here's an article with more on aging beef. For pork, poultry, and most other meats, the fresher the better. They do not improve with age.

Read the fine print when you shop. Try to avoid meats labeled "enhanced", "flavor enhanced", "self-basting", "basted", "pre-basted", "injected", or "marinated". They can have salty fluids injected, as much as 10 to 15% by weight. Why pay 10 to 15% more for salt water? In addition, kosher meat has been heavily salted in the koshering process and although the salt is rinsed off the surface, much of it seeps in. Many of these salted meats feel mushy when cooked because the salt denatures the proteins. You do not need these additives if you prep and cook the meat properly. If you want salt, you can add it yourself. If you cannot find a butcher who sells unenhanced meat, ask if he or she can special order it for you.

Shop safely. The dangerous strains of E-coli do not grow well at temps below 40°F, but an E-coli population on the surface of a steak can double every hour at room temp. Make grocery shopping your last stop when you're out running errands so groceries do not sit in you car any longer than they have to, and when you are in the grocery, make the meat counter the last stop. Put meat in the coolest part of your car. If your grocery is more than 30 minutes from home, on hot days bring an insulated box or bag for carrying refrigerated products.

For more, read my article on food safety for tips on shopping for meat that won't kill you or your guests.

Freezing meat

Use or freeze meat soon after you get it home. Have you noticed what happens when you thaw frozen meat? It can purge a lot of juice. That's because freezing forms sharp ice crystals that break open meat fibers. When those juices escape, there's no way to get them back in. You end up with dry meat. Frozen meat can be fine, especially if it is flash or blast frozen, a process that freezes it so quickly that the crystals remain small, do less damage, and create less purge.

If you must freeze meat, keep in mind that air is the enemy. Oxygen can speed degradation of fats, introduce odors, and it can promote discoloring and chemical change from freezer burn. I highly recommend vacuum devices like the FoodSaver products. You place food in a plastic bag, insert the open edge into the machine, and it sucks out the air and seals the bag. It can double or triple the time food stays fresh tasting in the freezer. If you don't have one of these nifty gadgets, put meat in a zipper bag, slip the closed end into a pot of cold water and let the water pressure push the air out the top, zipper end. Then zip the bag. This method takes a little practice, but it works. If you don't have zipper bags, take the meat out of those plastic trays and rewrap it tightly with plastic wrap and then with foil. Plastic wrap alone is permeable and will allow moisture to escape and allow air in.

Another important step is to freeze the meat rapidly so there are smaller ice crystals than if you freeze it slowly. To freeze meat most rapidly, bag it and remove the air and submerge it in icewater for a few hours. Water is a great conductor of heat and it will chill the meat quickly to just above freezing. Then place it on a rack in your freezer so there can be airflow all around, preferably right in front of the fan. Don't lay it on top of other frozen foods. Then wrap it tightly in foil. Frozen beef will stay pretty fresh tasting for six months or so, while pork, lamb, fish, and poultry can start tasting funky after three months or so.

You want to defrost meat slowly, so place it in the fridge. Click here to read my article about thawing foods.

Proper cooking temp

Because different cuts of meat vary significantly in tenderness, fat content, and collagen content, some must be cooked hot and fast to be at their best, some must be cooked low and slow, and some must be cooked with a combination on both to reach their optimum. Click here to read an article on the subject of cooking temps.

Proper serving temp

The higher the internal temp the meat achieves, the more water it squeezes out and the drier it gets. In general, most meats are juiciest and most tender when cooked to medium rare, 130 to 135°F internal temperature. But that's not hot enough for safety in some meats. Ground meats and poultry are health risks at those temps and they need to be cooked to 160 or 165°F to kill the pathogenic bacteria.

Meats with a lot of connective tissue such as beef and pork ribs, shoulder, brisket, or rump are too tough at these lower temps. They need to go up to 190 to 200°F in order to gelatinize collagens and melt fats. That's well past well done, and yes, water is lost, but the melted gelatin and fats lube the meat and make it tender and juicy.

Be aware that if you let meat sit around after you remove it from the heat, the heat built up in the outer layers will push down to the center and overcook the meat, a process called carryover.

The good news is that resting meat is an old husband's tale and it does little to improve juiciness. For more about ideal serving temps, read my detailed meat temperature guide with handy printout for your fridge.

Brown is beautiful, black is bad

As meat cooks, the most magical transformation is the Maillard reaction. It is named for a French scientist who discovered the phenomenon in the early 1900s. The surface turns brown and crunchy and gets ambrosial. Who doesn't love the crusty exterior of a slice of roast beef or the crust on a roasted marshmallow? We don't think twice about it, but that brown on the surface of a steak is hundreds of compounds that are created when heat, especially heat above 300°F, starts changing the shape and chemical structure of the amino acids and sugars on the surface of the meat. Click here to learn more about the Maillard reaction.

What you don't want is black meat. Let it go too far and it turns to carbon. Carbonized meat may be unhealthy.

Pretty in pink

Many smoked meats develop a smoke ring, a bright pink color just under the surface. Some people think the pink color means the meat is raw, but nothing could be further from the truth. It is a common phenomenon called the smoke ring.

The smoke ring in meat is caused by four things:

1) Low temperature cooking.
2) Combustion and the gases it creates, especially nitrogen oxides and carbon monoxides.
3) Moisture on the surface of the meat to help move the water soluble gases into the meat.
4) Myoglobin.

When these conditions are met, the gases in wood smoke reacts with the myoglobin in meat to form nitrites and nitrates. These are the same compounds added to hot dogs and other cured meats to preserve them and give them their distinctive pink color.

Moisture plays an especially vital role. The AmazingRibs.com science advisor Dr. Greg Blonder explains: "First, when it evaporates from the surface of the meat it cools the meat and this enhances condensation of nitrogen oxide. Second, the water is 'sticky' and grabs onto passing nitrogen oxides and flavor molecules. And third, it delays the formation of a dense bark which impedes absorption of smoke chemicals."

When smoke roasting, moist meat absorbs smoke more readily than dry meat. Less smoke is absorbed as the cooking continues because the surface of the meat begins to dry. For this reason putting a pan of water in a smoker helps create a smoke ring. In fact some smokers, called water smokers, have water pans built in. The Weber Smokey Mountain is the best known of this breed.

As combustion gases land on the surface of meat, especially cool moist meat from the fridge, they condense and some are moved deeper into the meat as cells lower in the smoke compounds pull them in by a diffusion and absorption process. The cells are simply seeking equilibrium. The process is the same as when someone lights a cigar in a room. All the smoke starts out near the cigar, but eventually it spreads throughout the room as it achieves equilibrium. After a while it penetrates clothes, furniture, and even food. Because it is water soluble, cigar smoke will get into wet things first, like your wife's eyes. Before long you and your cigar will be seeking equilibrium in the garage

A faux smoke ring can also develop without smoke if you cook low 'n' slow. When meat is cooked fast, the proteins in the muscle and myoglobin denature at the same time and combine to turn brown. When cooked slowly, the muscle proteins finish denaturing before the naturally pink myoglobin denatures and so the meat remains pink. You can occasionally see this phenomenon in braised meat like a beef stew. It may have been cooked for hours in a liquid at low temps, yet the meat will still be slightly pink inside.

On the other hand, some meats cooked low and slow in a smoky environment in an electric smoker will not develop a smoke ring. That is partially because the wood smolders at a low temp in electrics, and high temps (around 1200°F or so) are required to create the most nitrogen and carbon monoxides. Experts at cooking in electric smokers add a charcoal briquet as well as wood to create the correct atmospheric conditions for a smoke ring. Some of these briquets actually contain powdered sodium nitrates, which enhance ring formation. But in general, a vigorous charcoal or wood fire at just the right temperature, produces the deepest ring and the best meat. Click here to learn more about wood and smoke.

What causes properly cooked pork and poultry to be pink, even if it is not smoked?

Several factors: Gases in the atmosphere of an oven, particularly carbon monoxide, can react with hemoglobin in meat and turn it pink, especially on the outer edges. They occur in all ovens, especially those that heat by combustion such as gas, charcoal, or wood. They even are present in electric ovens. When grilling or smoking, there are more of these gases. They more easily penetrate the thinner skin and fat layers of younger animals, so age of the animal is also a factor.

Also, meats with high levels of naturally occurring compounds such as myoglobin, hemo-protein, and cytochrome C are more likely to turn pink. Nitrites in meat can also cause pinking. Nitrites are converted from nitrates in feed and water by microorganisms that are in the animal. Nitrates naturally occur in many leafy vegetables, and can transfer to the meat during cooking, from a rub or braise.

In fact, grocery store meat trays are occasionally packed with carbon monoxide or nitrogen to keep the meat in the pink.

The best way to test for doneness of any meat is to use a food thermometer. Color is not a reliable guide. Click here for a buying guide to food thermometers.

Why is red meat sometimes bright red on the outside and dull gray on the inside?

Fresh cut beef is purplish in color. Oxygen reacts with the pigments in red meat to form the bright red color of meat in the grocery store. The interior of the meat may be gray or brown because oxygen has not penetrated into the muscle. If, however, all the meat in the package has turned gray or brown, it may be spoiling.

Why does my meat shine like a rainbow?

It is simply a fluke of the right lighting striking the surface if the surface has been cut a certain way. Strictly refraction, not bacteria or an oil slick.

Why is my meat green?

Bad bacteria. Throw it out.

 

 

Here's a good video explaining the Maillard effect and caramelization

This page was revised 9/19/2011