Fifteen Seconds of Flame—a Steak's Own Story
Every cook knows that when you cook a good steak, you have to make painful compromises. You learn to blast it at high temperatures (a) because you need more than 300 degrees Fahrenheit to produce a crust with those rich, caramelized flavors that form like magic from the meat's natural sugars and amino acids. (Scientists call this process the Maillard reaction, named for the French physician who almost a century ago was the first to investigate similar reactions between proteins and sugars in the human body.) But you don't want the steak's interior to go much above 135 degrees, because that's the temperature at which it stays juicy and rare. Above that, the strands of proteins in the muscle fibers contract so much that they start to squeeze out their juices (b)—and beef has tons of juices before you cook it; it's more than 60 percent water. Renowned food science author Harold McGee shocked the cooking world in 1984 when he used these principles to demonstrate that searing meat at high heat does precisely the opposite of "sealing in" those juices—it starts to dry them out.
So what usually happens when you throw your steak on the fire? You end up with a great Maillard crust, a juicy rare or rosy center—and then there's a dry, chewy "gray zone" in between.
McGee had a hunch that computers could figure out a satisfactory solution. He knew that Silicon Valley scientists had used mathematical simulation software to help them study how electrons move through silicon chips, so he figured they could modify the software to study how heat moves through meat. They could. McGee ran hundreds of simulations, in effect asking the computer: What's the best way to get the heat to diffuse through the meat so it cooks as fast and evenly as possible?
The computer told them that chefs are cooking their steaks, well, wrong. McGee aims a laser pointer at his computer's simulation of beef, up there on the screen: The computer shows a simulation of the inside of the cooking steaks as sedimentary layers of purple and green and yellow, each color representing a different amount of accumulated heat (c). And they show that when you throw a steak on the fire and just let it sit there, sizzling away, and then you flip the meat only once before you serve it, you're messing with the heat diffusion. There's such a huge difference between the temperatures on the side that's facing the fire and the side that's turned away that the heat inside your steak fluxes all over the place. (This applies only to beef.)
"But," McGee says, "the computer model shows that if you keep flipping the meat as you cook it, the heat diffuses through the meat much more evenly, so it cooks much more evenly. Our study suggests that the optimum flipping time is every fifteen seconds."
Every 15 seconds? Can McGee be serious? "Maybe that's a little extreme; it might be inconvenient," McGee says, laughing. "The computer model shows that flipping the meat every thirty seconds will work almost as well." And it's nice to know that another recent study, at Lawrence Livermore National Laboratory, shows that frequent flipping makes steaks more healthful, too: It reduces the amount of carcinogenic compounds that can be generated when you cook over high heat by as much as 75 percent.
Which means that short-order cooks have been doing things right all along. —D.Z.
The Flavor Formula
Flavor = taste + aroma. On our tongue and soft palate, taste buds indicate salty, sour, bitter, sweet, or earthy (umami) (a). But flavor happens when the aromatic molecules in our nasal passages come into play. All foods contain light, volatile molecules, which easily float up our nasal passages (b), and large, heavy molecules that tumble down the throat (c). To maximize the flavor of a predominantly heavy-molecule food like starchy mashed potatoes, it should be spiked with predominantly lighter-molecule foods, like lime.
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