The Food Lab: Better Home Cooking Through Science

grazing along the ocean floor, like gigantic cows of the sea.
As such, their muscles don’t get much of a workout. Just as
with land animals, the less they use their muscles, the more
delicate they’ll be in both flavor and texture. It’s this
mildness that is prized above all in these white-fleshed fish,
and it’s a characteristic that we should attempt to maximize
during cooking. Just like steak and chicken, fish flesh will
dry out and toughen if cooked to too high a temperature.
Our goal with a fish like cod is to bring it up to around 150°
to 160°F—just hot enough to break down the thin, film-like
membranes of connective tissue between the layers of
muscle but not hot enough to dry it out.