How to Sear a Roast is from www.epicurious.com
A friend of mine (as well as my mom, when I was growing up), said something to the effect of "did you know that the point of searing a roast (or any other meat) is to keep the juices inside?"
Are you sure that searing actually keeps the juices inside?
From Wikipedia, the free encyclopedia
Searing (or pan searing) is a technique used in grilling, roasting, braising, sautéing, etc. that cooks the surface of the food (usually meat, poultry or fish) at high temperature so that a caramelized crust forms. A similar technique, browning, is typically used to sear or brown all sides of a particular piece of meat, fish, poultry, etc. before finishing it in the oven.
It is commonly believed that this acts to lock in the moisture or "seal in the juices" of the food. However, it has been scientifically shown that searing results in a greater net loss of moisture versus cooking to the same internal temperature without first searing. Nonetheless it remains an essential technique in cooking meat for several reasons:
The browning creates desirable flavors through caramelization and the Maillard reaction.
The appearance of the food is usually improved with a well-browned crust.
The contrast in taste and texture between the crust and the interior makes the food more interesting to the palate.
Typically in grilling the food will be seared over very high heat and then moved to a lower-temperature area of the grill. In braising, the seared surface acts to flavor, color and otherwise enrich the liquid in which the food is being cooked.
Sealing in the juices
The belief that searing meat "seals in the juices" is widespread and still often repeated. This theory was first put forth by Justus von Liebig, a German chemist and food scientist, around 1850. The notion was embraced by contemporary cooks and authors including Auguste Escoffier.
Simple experimentation can test the theory: cook two similar cuts of meat, searing one first and not the other. Weigh the end results to see which loses more moisture. (The Food Network program Good Eats carried out such a test in episode EA1H22, Myth Smashers.) As early as the 1930s, such experiments were carried out; the seared roasts lost the same amount of moisture or more. (Generally more, since searing exposes the meat to higher temperatures.)
In short, the crust created by searing is in no way waterproof. Moisture in liquid and vapor form can and does continue to escape from a seared piece of meat.