Every chef has their own technique when it comes to cooking, roasting, broiling or grilling for the best flavor, but most agree on one important step – meat should rest after cooking and before slicing.
For many people, letting meat rest is a habit passed on through family and friends but science shows that it’s actually a good idea. Letting meat rest helps to keep the moisture, or the stuff we call juices inside.
And all of that red juice isn’t actually blood. It’s a mix of water and myoglobin - another protein that stores oxygen and gives beef its pinkish-red color. ‘White meats’ like chicken and turkey don’t have as much myoglobin, which is why they appear lighter in color.
But why is it so important to let meat rest? Think about how a steak cooks in a pan.
Among all that sizzling, there’s a lot is going on. Meat shrinks and gets firmer, the color changes as fat breaks down, and those juices people love start seeping out of the meat.
All meat was once muscle on an animal, and muscles contain fibers that contract and relax to allow movement. They’re also what gives meat what we call it’s “grain.”
Within muscle fibers are two protein threads or ‘filaments’ called myosin and actin. During muscle contraction, the myosin threads grab onto actin threads, pulling them closer. Adding heat changes those fibers.
Myosin threads break down. changing their shape in a process called coagulation. That’s what makes the meat shrink. Water gets squeezed out of the muscle, which begins to happen at around 100 - 120°F. That’s notably, before a steak is cooked to a safe temperature to eat.
The actin breaks down at higher temperatures between 150 - 163°F. When that happens, your meat is going to get very firm as the process pushes even more water out. Leaving behind dry, over-cooked meat.
It’s why professional chefs aren’t usually so enthusiastic when a customer requests a steak well-done.
When meat is prepared properly, coagulated myosin proteins have a chance to relax a little bit once the heat source is removed. The moisture that had been squeezed out of the muscle fibers has time to seep back in, meaning you get a nice juicy steak.
One last note to keep in mind: recommended resting times can vary widely, but the thickness of the cut and method used to cook it play an important role.
According to chefs at America’s Test Kitchen, a thin steak or chop should rest about 5 to 10 minutes, while thicker roasts should rest 20 – 30 minutes. Larger portions, like whole turkeys or large roasts, should rest 40 minutes before carving.