The Food Lab: Better Home Cooking Through Science

Mexican Grill is serving food cooked sous-vide.
Here’s what’s great about it. Recall the problem of
temperature gradients developing in meat? To recap, food
cooks from the outside in, which means that the outer layers
are going to be hotter than the very center. Thus, cooked
foods develop an internal bull’s-eye pattern: perfectly
cooked at the very center and increasingly overcooked as
you move out to the edges.
So, for example, imagine you’re starting with a steak
that’s a consistent 40°F through and through. Place it in a
500°F pan, and the outer layers will almost immediately
reach around 212°F, the temperature at which the internal
moisture at the surface of the steak starts to evaporate.
Eventually all the moisture will dissipate and the
temperature of the outer layers of the steak will continue to
increase. It’s quite easy for those outer layers to achieve
temperatures in excess of 200°F (that’s beyond the well-
done 160°F stage for steak) before the core temperature has
even begun to shift. By the time the center reaches 130°F
(medium-rare), the outer layers are hopelessly overcooked.
Now imagine cooking the same steak in a constant 130°F
environment. Sure, it’ll take much longer for the center to
get up to 130°F, but it’ll get there eventually and, in the
meantime, the outer layers have no chance of overcooking.
That’s precisely what sous-vide cooking is all about. If
you place the meat in an airtight vacuum-sealed pouch and
submerge it in a temperature-controlled water bath, the
water very efficiently transfers heat energy to the steak
while maintaining a very precise temperature. The result is
meat that’s cooked evenly from edge to edge.