roast is the very image of a winter dinner. But lately you've probably been finding that the reality doesn't measure up. Too often that roast, so monumental in appearance, is nothing but a giant disappointment. What should be glorious and juicy turns out to be only tough and dry.
The fault isn't with the cook, but the cooked. Beef and pork are now raised to have much less fat than before and that can mean a disappointing dinner. Fortunately, it's a problem that is pretty easily solved by careful preparation, though it may take some retraining on your part.
To unravel this particular puzzle, we searched through hundreds of pages of scientific reports and cooked about a dozen roasts. We roasted pork and we roasted beef. We cooked them to medium temperatures and rarer. We used ovens that were blazing and hot, or gentle and slow, and some in between -- starting high and finishing low.
What we found surprised us. Looking at the sliced roasts side by side, the differences were astonishing. You might never have guessed that the only thing different about their preparation was the oven temperature. And the secret to the most successful -- a moist, delicious holiday roast -- was a low temperature, for the finished roast and for the oven in which it's cooked.
Don't panic, we're not talking about serving Uncle Bert bloody rare roast beef. When cooked at the lower oven temperature for a slightly longer time, a roast cooked to 125 F (normally quite rare) came out looking more like a conservative medium-rare. The meat was firm and definitely cooked through, but still juicy and flavorful.
Meat cooked in a hot oven, on the other hand, was still slightly raw in the center -- even though it had been cooked to the same temperature.
To understand how this works, you need to know a little bit about meat and heat. Roasts come from tender cuts of meat -- the muscles that didn't get much exercise. Because they have less connective tissue than other cuts, they can be cooked rarer and in an oven instead of a covered pot -- it's the stringy sinewy cuts that need the long moist cooking of a stew or braise.
Dry cooking -- roasting, grilling and sautéeing -- won't make meat more tender, but it does have one distinct advantage over moist. It can brown. The chemical reactions that cause browning in meat don't begin until the temperature on the surface reaches about 300 F. Since anything cooked with liquid present will never get hotter than the boiling point -- 212 F -- braised meat will never brown. That's why you sauté stew meat before you add any liquid. It's also why you should be sure to pat roasts completely dry before putting them in the oven.
It may sound redundant, but with these dry forms of cooking, dryness is always a problem. It isn't dry air that causes the loss of juiciness, but the effects of the heat. When meat roasts, the protein strands contract and squeeze out the moisture (up to 25 percent).
When there is fat in the meat -- either on the outside of the cut or the fine marbling within the muscle -- this isn't such a problem. The fat renders, too, and that makes them seem juicy even if there is less actual moisture in the meat.
And therein lies the rub. Responding to what it perceives as the consumers' demands, the meat industry has been working overtime for the past 20 years to reduce the amount of fat in its products. The percentage of fat in the average piece of pork has been cut by a third since the early 1980s. The percentage of fat in beef fell 27 percent from the early '80s to 1990 and, according to a beef industry spokesman, is "probably well below that now." In fact, some luxury cuts such as sirloin and tenderloin now meet government standards as "lean," low in fat and cholesterol.
The result has been to reduce the margin of error in roasting. Now, if you overcook meat even a little, your guests will know it immediately.
Instead of cooking beef to 145 F (on the medium side of medium-rare), we found that removing it from the oven at 125, then being sure to let it rest and rise to 135 yielded beef that was still firm but more moist. For pork, use 145 degrees instead of 160.
Left unanswered was the question of at what temperature you cook it.
For the answer, we roasted three beef and three pork loins of roughly the same sizes -- one at moderately high heat (450 F), one at moderately low heat (300 F) and one straddling the fence (450 F turned down to 300 F after 15 minutes).
When the roasts were done, we removed them from the oven and set them aside for 10 to 15 minutes to rest. This is standard practice for roasting, though it is often overlooked in the cook's rush to get dinner on the table. It is important because it allows the roast to finish cooking with the residual heat in the meat. The internal temperature will increase from 5 to 15 degrees during the rest, depending on the size of the cut (smaller cuts retain less heat). Also, it allows the meat's juices, which have been driven to the center by the heat of cooking, to redistribute evenly through the roast.
We cooked the beef to an internal temperature of 125 F. After a 10-minute rest, it was at 135 F, on the rare side of medium-rare -- definitely moist and reddish pink, but the muscle fibers were set, not raw.
The pork we cooked to an internal temperature of 145 degrees (rising to 155 after the rest). This is somewhat lower than the current USDA standard of 160 F, but well above the minimum for safety. Pork needs to be held at 140 F for less than a minute to eliminate any threat of trichinosis.
What we found in our roasts was that high temperature roasting does develop a marginally better crust, but that is more than offset by a distinct toughening of the meat. The roasts cooked at 450 F were chewy and a little dry in the outside portions and were still quite rare in the center. Except for the browning in the crust, the flavor was a little weak.
The meats cooked at low heat were more tender and moist as well. And, except for the very outer crust, the meat had better flavor -- it was fuller and meatier. While the exterior lacked some of the crust of the high-heat roasts, it didn't seem enough to tip the balance.
The roasts cooked first at high heat, then at low, were right in the middle. Their crust wasn't as good as the high-temperature roasts and they weren't as tender as the low.
The differences among cooking methods were particularly profound with beef. Not only was the high-heat loin not as good; there was less of it. The high-heat loin weighed 25 percent less after roasting, compared with a 15 percent shrinkage for both low-heat and high-low.
