When I really want to pamper guests who love good food, I use a good roast beef ribs tasty, tender and juicy enough. For meals every day, I turn instead to more affordable roasts such as round or sirloin tip. Inedible, you say? Not if you know the magic of roasting at low temperatures.

To better understand how cooking can tenderize the meat, let us first on the effects of heat on muscle fibers and collagen, which are the two main components of a roast.

Tender roast beef - Muscle fibers

These fibers are the main components of the meat. They are long cells that contain protein and plenty of water. During cooking, the protein fibers coalesce - tighten - and expel the water that surrounds them, just as you would off a towel. The higher the temperature rises greater the juices to evaporate the meat. Research has shown that the meat begins to expel its juice when it is still rare, i.e. when its internal temperature reaches 55 to 60 ° C (135 to 140 ° F). Meat reaches an internal temperature of 77 ° C (170 ° F) - a degree of cooking "cooked" - will have lost up to 40% of its water. That's why overcooked meat is always dry.

Research has also found a positive effect of cooking on meat. This is the phenomenon of tenderizing enzyme. The muscle fibers contain enzymes that attack fibers and expect. These enzymes are only active when the internal temperature of meat reaches between 50 and 60 ° C (130 and 140 ° F). More meat is kept long at these temperatures, it will be tenderer.

Tender roast beef - Collagen

The other important part of the meat is a thin white fabric and elastic. It also composed of protein and collagen surrounding the muscle fibers. These fibers are grouped in bundles of several hundred gathered in their lap and wrapped them as collagen, in even greater quantity, and the ends to form a muscle. Collagen acts as a sort of sheath that holds all fibers and bundles. It was this assembly which determines the "grain" of a cut of meat. The muscles most in demand in animals - those of the neck, shoulder, chest and thigh - contain more collagen than muscles that are less like those back and ribs (loin) , making it less tender cuts.

In raw meat, collagen is very tough and elastic. Fortunately, cooking expect. With the heat and humidity, the chemical bonds that hold together the molecules break down collagen and collagen turns into gelatin, easy to chew.

But there is a catch: this transformation requires a long cooking, or high temperature. More will be long cooking, the greater the amount of collagen that will turn into gelatin and the meat is tender. As against, if you cooked the meat well in high temperature, its muscle is tightened too much and expel their juices. And the meat is dry. A perfect cooking of meat requires compromise.

Tender roast beef - Roasting at low temperature

It was in the habit of cooking the roast in a preheated oven between 170 and 180 ° C (325 to 350 ° F). However, more and more specialists of cooking meat advocated a lower temperature, from 120 to 140 ° C (250 to 275 ° F). Why? Because at this temperature, the heat takes longer to move from the outside toward the center of the roast. The interior remains longer in the temperature range that allows the tenderness by the action of enzymes and then by the transformation of collagen into gelatin.

Another advantage with a low cooking temperature, the coagulation of muscle fibers is slower and less water is expelled. We obtain a more uniform cooking and meat more tender, whose color is almost uniform throughout. It will also be very lucrative, provided they do not cook beyond an internal temperature of 71 ° C (160 ° F), equivalent to a degree of doneness "point."

Roasting at low temperature, however, has only one small disadvantage: the piece of meat that is cooked in this fashion will not crust brown and tasty, as is the case when baked warmer. Solutions: start baking in an oven preheated to 260 ° C (500 ° F) for 15 to 20 minutes or brown the roast on all sides in a pan before you bake.

Tender roast beef - Less tender cuts cooking at 140 ° C (275 ° F)

Found in the meat from supermarkets a wide selection of roast beef from less tender parts. The sirloin tips, rump, outside and inside round, for example, are often neglected and roasts always offered at very competitive price. To promote tenderness by enzymes and to give all the time required converting collagen into gelatin, these cuts must be cooked a long time at low temperatures. Ideally, there is bleeding or the medium-rare, sliced very thin. See this recipe for roast beef easy and economic Ricardo.
Tender cuts cooking at 170 ° C (325 ° F) or 140 ° C (275 ° F)

Roasts from tender cuts such as the coast or the net contain little collagen. With them, we do not need to take special care to be expected. They are juicy provided they do not cook too. The Information Center recommends simply beef cooked in an oven preheated to 170 ° C (325 ° F). It is a simple and proven technique that gives good results. And if you have some time before you let them cook in an oven set at 140 ° C (275 ° F). The cooking time will be extended, but your patience will be greatly rewarded. The meat literally melts in your mouth!

Tender roast beef - Tough cuts cooking pot-au-feu

The pot-au-feu, also called simmered or braised, use a classic technique of cooking to tenderize the roast from toughest cuts such as shoulder, chest and the palette. The piece of meat is golden on all sides in a pot, a fragrant and tasty liquid (broth, wine) and herbs (herbs, onion, celery). It should be well then cover and simmer at length, until it is way out with a fork. There is a good example of this mode of cooking with slow baked beef and whiskey fennel.

Tender roast beef - Rapid heat

In a moist cooking like a roast, heat is transferred more quickly to the meat in a dry oven. The principle is the same as the potatoes, which cooks more quickly in boiling water and oven, without water. Under conditions of high heat and humidity, the sheath surrounding the collagen fibers are easily transformed into gelatin, which allows muscle fibers to detach from each other.

However, with this method of cooking, the meat fibers shrink, expelling almost all their water and become dry. How, then, explain that roasts stews are still juicy? In fact, it is an illusion! One has the impression that the meat is juicy because of the cooking liquid has seeped into the spaces between the fibers.

While traditionally, stews are cooked in the oven at 170 ° C (325 ° F), they could be cooked to 120 or 140 ° C (250 or 275 ° F). In this way, the meat may dry out less. How long should I cook? Hard to say ... we go by the size of the roast. We must continue cooking until the meat is to undo the range, which can take between three and four hours.

With a low cooking temperature, one obtains a more uniform cooking and meat more tender.

Tender roast beef - Rapid heat

In a moist cooking like a roast, heat is transferred more quickly to the meat in a dry oven. The principle is the same as the potatoes, which cooks more quickly in boiling water and oven, without water. Under conditions of high heat and humidity, the sheath surrounding the collagen fibers are easily transformed into gelatin, which allows muscle fibers to detach from each other.

However, with this method of cooking, the meat fibers shrink, expelling almost all their water and become dry. How, then, explain that roasts stews are still juicy? In fact, it is an illusion! One has the impression that the meat is juicy because of the cooking liquid has seeped into the spaces between the fibers.

While traditionally, stews are cooked in the oven at 170 ° C (325 ° F), they could be cooked to 120 or 140 ° C (250 or 275 ° F). In this way, the meat may dry out less. How long should I cook? Hard to say ... we go by the size of the roast. We must continue cooking until the meat is to undo the range, which can take between three and four hours.

With a low cooking temperature, one obtains a more uniform cooking and meat more tender.

Unfortunately, there is no table of cooking times for roasting at 140 ° C (275 ° F). You can use the tables for cooking to 170 ° C (325 ° F) as a reference. One must be aware that such a table is useful but not infallible.

Too many variables such as the presence of bones, the shape of the roast and the temperature enfournage can affect cooking time proposed. It should also be noted that over the roast is big, require less cooking minutes per pound. Using a meat thermometer is therefore the surest way to guarantee a perfect cooking your roast.
Cooking time roasts to 170 ° C (325 ° F)

These times are valid for cold roasts, placed directly in the oven preheated to 170 ° C (325 ° F)

Tender roast beef - Cooking time roasts to 140 ° C (275 ° F)

Enter first roasted in a pan or bake in an oven preheated to 260 ° C (500 ° F) for 15 to 20 minutes. Then cook in oven at 140 ° C (275 ° F). To determine the cooking time, add 30 to 45 minutes at the time indicated in the table above. For example, a roast 1.5 kg (3 lb) medium-rare, count 1 hour, plus 30 to 45 minutes or 1 h 30 1 h 45.