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.
A tough cut of meat can be made meltingly tender. We see this in barbecue. We see this in brisket. We see this in slow-roasted pork shoulder. The common denominator? They’re all cooked to death.
Cooking tough cuts way beyond well-done breaks down collagen, turning it into gelatin. How? Well, collagen is composed of three protein chains tightly wound together in a triple-stranded helix. When raw, collagen is pretty much unchewable. But when cooked, things change. At 140 degrees, this helix begins to relax, unwinding into individual strands—in essence, forming gelatin.
Above: At temperatures above 140 degrees, the triple helix of collagen unwinds to form three strands of gelatin.
The single strands of gelatin are important because they can retain up to 10 times their weight in moisture, tenderize meat, and add an essential and luxurious richness to sauces in braised dishes. The longer a tough cut of meat is held at a temperature above 140 (though preferably 160 to 180 degrees) the more collagen will unwind into gelatin. And the more gelatin the more tender your final dish.
We knew all this in theory when we sat down to write a chapter on collagen and gelatin in The Science of Good Cooking. But how to prove it? Well, it all came down to Jell-O in the end.
Not actual Jell-O, not really. But the texture of that favorite 1950s dinner-party dish relies on gelatin. And our goal was to convert as much collagen to gelatin as possible.
Associate editor Dan Souza began by cleaving 1 pound of oxtail (an almost obscenely collagen-rich cut of meat) into rough ½-inch pieces (chopping through the bone).
He threw these pieces into a saucepan filled with just enough water (dyed dark brown for maximum visibility) to cover the meat.
He brought the liquid to a simmer on the stovetop and then cooked the covered pots in a 325-degree oven for 3 hours—every 30 minutes removing ¼ cup of the braising liquid, which he poured into a plastic cup and then transferred to the fridge to cool and set.
The goal was to see the amount of gelatin present in the water—and how long it took to get there. After all, with time, the collagen in that oxtail should be rendering into gelatin, which should then be leaking out into the braising liquid. We wondered: Would there be enough to make a veritable Jell-O mold?
When all the samples had fully chilled, we peeked into the fridge to see.
The 1-hour sample didn’t show much change, especially not when Dan dumped it out onto a plate. It turned into an unpalatably mushy brown soup.
The 2-hour sample, however, was a bit firmer. When Dan tipped it over onto a plate, we could still see some of the sharp corners of the cup in which it had chilled. Clearly, more gelatin had leached out into the braise. And after 3 hours?
The oxtail in the pot had been in shreds, and the chilled braising liquid plopped out of its cup into a firm mound of oxtail Jell-O. It may not have been a dish anyone would want to serve at a dinner party, but it was pretty awesome nonetheless.
MAKE IT NOW
Our recipe for Slow-Roasted Pork Shoulder with Peach Sauce is free through November 19, 2012.
Got any jiggly questions? Leave 'em in the comments.