size, makes them the most expensive cut (that whole supply-
and-demand thing, you know?).
Out of these two muscles come a number of different
steaks. The chart here shows what you’ll find at the typical
butcher shop.
Q: Why would I want to eat steaks from these muscles?
The tenderness of a steak is inversely related to the amount
of work that the muscle does during the steer’s lifetime. So,
as relatively unused muscles, the longissimus dorsi
(commonly referred to as the loin or backstrap) and the
psoas major are extremely tender, making them ideal
candidates for steak (and also quite expensive). The former
has an advantage over the latter in that it contains a
generous amount of fat, both in large swaths around the
central eye of meat and, more important, within the muscle
itself in a web-like network known as marbling.
Q: Why is marbling important?
Mainly because it lubricates the muscle fibers. At room or
fridge temperature, the fat is solid, but when cooked, it
melts, helping muscle fibers slip around each other more
easily as you chew, resulting in more tender, juicier meat.
Marbling is also important because most of the flavor in red
meats comes from the fat. Indeed, there are studies in which
tasters fed portions of lean beef and lean lamb were unable
to identify them correctly but were easily able to do so when
given a portion with fat. Fatty beef just tastes beefier.
Grading