Holidays : The Art of the Roast

Browned and meaty, yet pink and tangy. Crusty outside, yet buttery inside. Firm, yet tender. Juicy, but not stringy. The art of roasting is the art of compromise.

It is one of the oldest forms of cookery, and it is one of the grandest. For most cooks, it is also one fraught with concern.

“We can learn to be cooks, but we must be born knowing how to roast,” wrote the French culinary philosopher Brillat-Savarin in “The Physiology of Taste” in 1825. But that was before the invention of the instant-read thermometer. If it’s a roaster you want to be, there can be no better way to spend $10 than to run down to the grocery store and pluck one off the housewares shelf.

Different from the traditional meat thermometer--those notoriously inaccurate things that stay in the meat throughout the cooking process--an instant-read thermometer gives you a quick and exact reading. Just plunge it into the roast at its thickest part (being careful to stay away from the bone), and within a minute you know where you are.

In roasting, temperature is all.

In a study called “Flavor, Color, and Other Characteristics of Beef Longissimus Muscle Heated to Seven Internal Temperatures,” ag scientists at Kansas State University found that “Beef flavor components and juiciness change most from 130 degrees to 150 degrees, then little change takes place until meat is heated to temperatures between 175 and 185 degrees, when browned and mouth-filling blend components increase and juiciness decreases.”

In other words, these guys roasted beef loin from very rare to very well-done. What they found was that the peak temperature for flavor and juiciness was between very rare and medium-rare (on the USDA scale).

A group from the University of Missouri college of agriculture did the same thing with pork. Their findings? “The optimum endpoint temperature for fresh pork roasts should be at least 160 degrees and should not exceed 170 degrees.”

Though studies on lamb are harder to come by (it’s not as big a market and hence affords less research), one 35-year-old study found that legs of lamb “have an odour and taste more characteristic of lamb” if cooked to 150 degrees than to 165 degrees (135 for rare lamb).

Being a rare-lamb guy from way back, I was tempted to put that down as nothing more than the pottering of a bunch of guys who knew neither how to cook nor to eat. Then I tasted a chop from a rack that had been accidentally overcooked to about 145 degrees. It was absolutely delicious and the texture was unbeatable.

Anyway, what it all comes down to is meat and heat. There are many things that happen when you cook a roast.

* Flavor changes as cell walls break down, mingling amino acids and proteins.

* Texture changes, from stringy and tough to firm and buttery, and finally to dry and tough.

* Juiciness (a function of both water in the meat and the saliva in the taster’s mouth produced in reaction to the presence of fat) decreases as the water is squeezed from the meat fibers and the fat is rendered.

* Finally, and actually fairly unimportant to the cook, color changes (at least in beef and lamb) from red to brown. This is not, as one might suppose, because of the blood leaving the meat (in properly slaughtered meat, there is little blood left), but because of a molecular change in two related pigments called myoglobin and oxymyoglobin (pork, lacking these chemicals, is never red).

The flavor of well-roasted meat is a combination of two things. The first, called the Maillard reaction, is a series of chemical reactions that occurs when amino acids are heated in the presence of sugars. That’s not as scary as it sounds. Cooks call it “browning.”

The important thing to remember is that these reactions don’t begin to produce the smells and flavors we associate with browning until a temperature of 335 degrees is reached. Obviously, this is a temperature that can be reached only on the exterior of the meat.

At the same time, in the interior of the roast, other chemical and physical changes are occurring. These result in a steady decrease of the beef-flavor aspects scientists have labeled “bloody-serumy,” “metallic” and “sour,” and a fairly steady increase in what they describe as “mouth-filling.” (They are scientists, not poets.) In pork, the flavor change is from “metallic” to “sweet.”

The textural changes are also progressive. Technically, what is happening is the denaturing of myofibrillar and sarcosplasmic muscle proteins and the solubilizing of collagen fibers. Essentially, what that means is the stringy muscle fibers progressively shorten and tighten while at the same time the tough connective tissue turns to a kind of jelly. This reaches an optimum for beef between 130 degrees and 150 degrees, when a second toughening process begins.

Meat becomes less juicy the more it is cooked because as those heated muscle fibers shorten, water is squeezed from them and fat is rendered. The juiciness of beef drops steeply between 140 to 150 degrees (roughly rare to medium rare). By the time it reaches 175 degrees, it has lost more than 40% of its weight. For pork the drop is steadier, but most pronounced between 160 and 170 degrees.

Finally, the color of beef and lamb changes as pigments called myoglobin and oxymyoglobin, which are red, lose an iron molecule and convert to metmyoglobin, which is brown. This by itself has no effect whatsoever on flavor or texture, but since it happens at roughly 140 degrees and above, it is useful as an indicator.

Now that you know where you’re going, the only question left is how to get there.

In The Times Test Kitchen, we experimented with three different means of roasting. First, we cooked a rack of lamb and a leg of lamb at high heat--450 degrees--until they reached 135 degrees. Then we cooked the same cuts--as nearly identical in weight as possible--at a slow 325 degrees.

Looking at them side by side, the biggest difference was the color of the exterior. In the high-heat versions, the meat was nice and crusty brown. At low heat, the roasts were paler. The differences on the inside were not as great. The high-heat roasts tended to be a little stringier or more fibrous at the center; the ones cooked at lower heat were more uniformly buttery in texture.

To get the best of both, we figured we’d compromise. Since beef and lamb cook to a relatively low internal temperature, it’s important to start them in a very hot oven--450 to 500 degrees--to bring the surface to a high heat faster and start the browning process. (With smaller cuts of meat, you can accomplish this also by browning the meat in a saute pan on top of the stove.) After 15 to 20 minutes, reduce the heat to around 325 to 350 degrees and let the roast cook slowly and evenly to the proper temperatures.

With pork, the situation is a little different. Since it cooks to a higher interior temperature, the initial browning is optional--by the time the center of the roast hits 160, the exterior will already have begun to brown, but perhaps not enough for you if you’re not using a spice coating on the meat.

And by starting in a hot oven, you run the risk of overcooking a greater portion of the meat, resulting in dry, gray pork. We prefer to cook pork low and slow.

Remember, in all cases, the meat continues to cook after it is removed from the oven because of heat retained within the roast itself (the bigger the piece of meat, the more “push” you get). So subtract five degrees from smaller cuts and 10 or more from larger cuts in order to make the perfect compromise.

Ideal Roasting Temperatures

Beef: 130 to 140 degrees.

Lamb: 135 to 145 degrees.

Pork: 155 to 165 degrees.

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Making the Cut

Basically, all roasting cuts come from the rib and loin portion of the animal (the back between the shoulder and the hip) or, with smaller animals, the legs. Meat terminology is confusing, and the names of cuts change from region to region, sometimes even from store to store.

BEEF

Ribs and Loins:

* Standing Rib Roasts (these are called Prime rib only if they come from an animal that has been graded Prime). They are divided as follows:

First-Rib Roast (5 to 8 pounds). Actually the 11th and 12th ribs, this holds the most rib eye and is the most expensive.

Center-Rib Roast (5 to 8 pounds). Holds a smaller part of the rib eye and is less expensive.

Sixth and Seventh-Rib Roast (5 to 8 pounds). Holds mainly shoulder and chuck and is not very tender.

Rib Eye or Delmonico Roast (3 to 6 pounds). Same cuts, without bones.

* Sirloin (8 to 12 pounds). The back end of loin.

* Tenderloin (4 to 6 pounds). Smaller muscle under the short loin.

PORK

Loin and Rib Roasts:

* Center Loin (3 to 5 pounds). Holds a lot of tenderloin.

* Sirloin Roast (3 to 4 pounds). Holds some tenderloin, with hip bone.

* Half Loin Roast (5 to 7 pounds). Half of loin, plus either sirloin or shoulder loin.

* Rolled Loin (3 to 4 pounds). Same cuts, boned and rolled.

* Crown Roast (6 to 10 pounds, and up). Two half loins tied into circle.

* Tenderloin (3/4 to 1 1/2 pounds). Small muscle under the loin.

Leg:

* Boston Butt (4 to 6 pounds). Upper part of forward shoulder.

* Fresh Picnic (5 to 8 pounds). Lower part of forward shoulder.

* Fresh Hams (10 to 14 pounds). Rear leg. Can also be purchased in butt (shoulder) portions (5 to 7 pounds) and shank (leg) portions (5 to 7 pounds).

LAMB

Loin and Rib Roasts:

* Rack (2 1/2 to 3 pounds). The back part of the ribs.

* Crown Roast (6 pounds and up). Two racks tied in circle.

* Loin (2 to 2 1/2 pounds). Meaty section back of the rack.

* Saddle (4 to 5 pounds). Double loin with backbone.

Leg

* Whole (6 to 10 pounds). Always the rear leg. Can be divided into sirloin (shoulder) half (4 to 5 pounds) and meatier shank half (3 to 5 pounds).

Food styling by Donna Deane and Mayi Brady