There is a
widespread belief that
browning the
surface of
meats seals in
moisture and allows the final
creation to be
juicier than if it were not immediately browned. The idea is that the
caramelization of
sugars in the surface of meats creates a "
crust" that keeps
evaporating moisture from
escaping.
From
Le Cordon Bleu's
Professional Cooking (a
standard introductory textbook in many
culinary schools):
"This does not actually happen. Meat does not have
pores but is an
open network of
fibres. Think of the surface of a
steak as resembling the
cut end of a thick rope. It is true that heavy browning creates a kind of crust on the surface of the meat, but this crust is no more
waterproof than an unbrowned surface."
It's really quite
obvious why this must be true. Consider
brown braising, which is the process of cooking an item
partially submerged in a
liquid after it is browned. The
principle behind braising--
tenderizing through the
absorption of moisture into
connective tissues--could not possibly work if browning were done first. The waterproof "seal" would
logically allow no water to enter, and therefore the technique would not work.
On a more
extreme note, it's
plausible that if meats were
sealable in this way, then we'd be in
grave danger of meat
exploding from
water pressure, ala a
baked potato.