On October 3, Christopher Kimball, Guy Crosby, and Dan Souza will present scientific experiments and delicious surprises at a sold-out event at the Museum of Science, Boston. See if we’re coming to your city on our national tour schedule.
Recipes engineered for perfection—what exactly does that mean? The Science series takes you inside the experiments behind 50 cooking concepts featured in our new book, The Science of Good Cooking, by the editors of Cook’s Illustrated.
We’ve all had that magical restaurant moment: savoring an obscenely flavorful piece of meat, one so tender you could cut it with a butter knife. At home, however, we sometimes have to slice through the same cut (though this time bland) with a saw. What’s going on?
It all comes down to time.
You’ve all seen the label: dry-aged beef. It seems to be everywhere these days—from specially refrigerated shelves at the butcher store to the menu at fancy steakhouses. It’s more expensive. It’s more tender. It tastes better. But why?
Aging is a technique used by many restaurants on primal cuts of beef in order to create more tender, flavorful meat. To age beef, it is allowed to sit undisturbed in a humid refrigerator ranging between 32 and 40 degrees for up to 30 days. Yes, that sounds like a long time. But a lot happens during those days. A significant portion of moisture is lost and the muscle proteins begin to break down. But most important is the activity of enzymes.
Enzymes are a type of protein. One of their functions in living animals is the turnover and processing of other proteins around them. In meat, these enzymes continue to catalyze change. Here, there are two enzymes at work: calpains and cathepsins. They are both important. Calpains break down the proteins that hold the muscle fibers in place. Cathepsins break apart a wider range of proteins and can even weaken the collagen in the muscles’ connective tissue. Both have the ability to impart a meatier, umami taste and to tenderize.
The activity of these enzymes depends entirely on temperature. They are active when held between 32 and 40 degrees, but move slowly, which is why dry-aged meat held in a refrigerator needs 30 days. The rate of activity increases, however, as the temperature rises—right until it reaches 122 degrees. That’s when everything comes to a halt.
In the test kitchen, we wondered if we could use this enzymatic activity to our advantage when cooking meat at home. If we roasted meat very slowly, purposely keeping the temperature below 122 degrees to encourage enzymatic activity for as long as possible, giving the enzymes leave to work overtime, would this in effect “age” the roast within a few hours? Associate Editor Dan Souza devised an experiment to test just that.
Dan began by cutting one two-rib standing beef rib roast into two equal steaks. He cooked one in a sous vide water bath held at 120 degrees for two whole days (48 hours). He cooked the second in the same bath—but just until its internal temperature hit 120 degrees, which took about 2 hours.
To determine the effects of enzyme activity below 122 degrees, he devised a stress test.
Dan cut ¼-inch-thick, 4-inch-long cross-grain slices from the same part of each steak and suspended each vertically, holding them up with tongs.
To the other end of the steak strips, he attached 2-pound weights.
And then he waited.
Well, he didn’t have to wait that long. When Dan hung the slice of meat that had cooked for 48 hours, it tore in half immediately, the weight plopping down onto the counter in a split second. The second steak, however, hung in there for a good 15 seconds, stubborn and intact.
What does this tell us? Well, for one, internal temperature isn’t the only factor in determining tenderness in meat. After all, Dan cooked both samples of meat to the exact same temperature; the only difference was the length of time he held them there. Held under 122 degrees (in this case, at 120), the enzymes present in the meat did their best work. In the 48-hour sample, the enzymes had much more time to work their magic, which is why the meat was so tender it fell apart immediately. The sample brought right up to temperature was much less tender because it didn’t have the benefit of that extra enzymatic activity.
Don’t get us wrong. We’re not saying that the home cook should spend two days gently bathing a steak for dinner. Even an hour of enzymatic activity makes a difference. We like to roast meat slowly and gently, giving the enzymes as much time as possible to do their work. This technique is best for cuts with little connective tissue, ones ideally cooked no further than medium.
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Our recipe for Slow-Roasted Beef is free through October 15, 2012.
Got any meat questions? Leave 'em in the comments.