Grill meat scientifically and become the coolest guy at the table!

As the weather warms up, it's time for a picnic and a barbecue. Although some people don't eat beef often for various reasons, the temptation of having a steak every once in a while is still hard to resist - you'll look forward to the experience.

So what's the best way to sear a steak? There's some science to the answer.

Meat scientists spend their entire careers studying how to produce the most tender, flavorful beef possible. Although most of their research topics are only of reference significance to cattle producers and processors, some of their findings can also provide some guidance to grill chefs on what kind of meat to choose and what details to pay attention to during the grilling process .

Let's start with meat selection . Every experienced chef knows that the loin muscle tissue near the spine is less exercised and has less connective tissue, making it more tender than the regularly exercised leg muscles. And they know to look for steaks that are well-marbled , which are deposits of fat that fill in between muscle fibers and are a sign of high-quality meat. "If there is more marbling, the meat will be more tender, juicy, and have a richer flavor," said Sulaiman Matarneh, a meat scientist at Utah State University, who published a paper on muscle biology and meat quality.

In fact, the flavor differences between steaks are mainly due to fat content, which refers to both the amount of marbling and the composition of the fatty acid subunits in the fat molecules. Premium cuts like ribeye steaks have more marbling and are richer in oleic acid, a very delicious fatty acid. "This fatty acid gives people a great taste experience," said Jerrad Legako, a meat scientist at Texas Tech University. In contrast, sirloin has less oleic acid and more of other fatty acids, which makes it produce a less appealing fishy smell during cooking.

This difference in fatty acids is also reflected in the choice of consumers when buying steak: grain-fed beef or grass-fed beef ? Grain-fed cattle, which mainly feed on corn and soybeans and live in feedlots until the end of their lives, have richer oleic acid in their meat; animals that have been eating grass on pastures all their lives have a higher proportion of omega-3 fatty acids, a polyunsaturated fatty acid that can be broken down into small molecules with a fishy smell. In any case, more consumers prefer to buy grass-fed beef, either to avoid the ethical issues of feedlots or because they prefer wild and lean meat.

The diet of beef cattle affects the flavor of their meat. Grain-fed cattle, such as the ones shown here from a California feedlot, produce meat that is more marbled and fattier than grass-fed cattle, which spend their entire lives grazing on pasture. Grain-fed beef also has a higher percentage of oleic acid, a fatty acid that most people find particularly delicious. Grass-fed beef has a higher percentage of omega-3 fatty acids, which break down during cooking into compounds that give it a fishy, ​​gamey flavor.

Image credit: Jim West

However, the cooking method has the greatest impact on the final flavor of the steak. Cooking can improve the taste of meat in two ways: high temperature grilling can break down the fatty acids in the meat into smaller molecules , which are more volatile, that is, easier to spread through gas. These volatiles are the main source of the aroma of steak and largely determine the taste of steak. Among them, aldehydes, ketones and alcohol molecules are the substances that bring us a rich taste experience.

The second way cooking enhances flavor is through browning , a process chemists call the Maillard reaction. This reaction is extremely complex, starting with amino acids and trace sugars in the meat reacting at high temperatures, which then triggers a series of chemical changes that lead to many different volatile end products. The most important of these are molecules called pyrazines and furans, which give steak lovers the roasted, nutty aromas they desire. The longer you cook and the higher the temperature, the more Maillard reaction progresses, and the more desirable end products you get—until eventually, the meat starts to char and develop an unpleasant bitter, burnt taste.

"Thin steaks cook faster, so they need a hot grill to get enough browning in a short period of time," said Chris Kerth, a meat scientist at Texas A&M University. Kerth and his colleagues studied the process in the lab, grilling steaks with precision and putting the results through a gas chromatograph to measure the amount of each volatile chemical produced.

As expected, Kers found that cooking a thin steak, about a half-inch thick, at a relatively low temperature had the most intense beefy flavor from the breakdown of fatty acids, while higher temperatures also had a lot of toasty pyrazines from the Maillard reaction. So if your steak is thin, turn on the grill, leave the lid off, and let the meat cook slowly. This will give you enough time to develop a rich, deep beefy flavor.

To get an attractive browning on both sides of the meat, flip it about a third of the way through the total cooking time, rather than waiting until halfway through—because Kers' team found that when you cook the first side, the contracting muscle fibers transfer water to the uncooked side. After you flip it, that water cools the second side, so it takes longer to brown.

The flavor of steak comes primarily from small molecules that are created when you cook meat. Here are some of those molecules and the flavors they impart. If you're a meat lover, see if you can pick out these flavors in your next steak.

When the scientists tested thicker 1.5-inch steaks, a paradox emerged: The outside of the steak would unfortunately burn before the center was done. For these steaks, the right grill temperature maximized the mixing of the volatiles. When the tasters tasted the steaks from Kers' team, they gave lower scores to the thick steaks that were grilled quickly at high temperatures. The diners had a slight preference for the steaks cooked at medium temperatures, but their ratings of the other temperatures and cooking times were similar.

This may seem strange, since steakhouses often advertise their prime thick cuts of beef and high-temperature grills—the very combination that Kers's research found to be the least desirable. It works because steakhouses use a two-step cooking process : First, they sear the meat on a hot grill, then finish it in an oven at the right temperature. "That way, they can get the sear they want and the doneness they want," Kers says. Home cooks can do the same thing, putting the roast in an oven at 175 degrees Celsius until it reaches their desired doneness.

Of course, optimal doneness is largely a matter of personal preference—but science has something to say on this front, too: "Rare meat hasn't received enough heat to break down the fatty acids, so it has a strong raw beef flavor," Kers says. Once you go past medium rare, you start to lose some of that 'bloody' flavor of rare meat. "A lot of people, myself included, like the 'bloody' flavor of pyrazines and Maillard compounds, which are more intense," Kers says. For these reasons, he advises: "I wouldn't go for less than medium rare, and certainly not above medium rare. Otherwise you start to miss out on a lot of flavor."

Kers has one more piece of advice for home cooks: When the meat is on the grill, watch it carefully! "When you get the right cooking temperature, a lot of things happen in a short period of time, and a lot of chemical reactions happen very quickly from the beginning." It's a scientific rule that every experienced griller has learned the hard way: If you don't pay attention, meat will burn easily.

I wish you all a happy barbecue in a scientific way!

By Bob Holmes

Translation: Depth

Reviewer: Zang Chi

Original link: Sizzling science: How to grill a flavorful steak