The Food Lab: Better Home Cooking Through Science

crackling skin that everyone fights over?
A full bone-in Boston butt is a formidable piece of meat,
usually weighing in at around 8 to 12 pounds, riddled with a
significant amount of connective tissue and inter-
/intramuscular fat, all swathed in a thick, tough skin. Our
goal is to make this tough piece of meat spoonably tender.
How do you do that? Well, first we need to understand the
difference between the two major types of muscles in an
animal.
Fast-twitch muscle is the stuff that the animal rarely uses,
except in short bursts: The breasts on a chicken that let it
flap its wings rapidly when escaping danger. The loins on a
cow that, well, barely get used at all. Fast-twitch muscle is
characterized by tenderness (think chicken breast, pork
chops, and New York strip steaks) and a fine-textured grain
and is best prepared using fast-cooking methods like
roasting, grilling, or sautéing (see Chapter 3). With fast-
twitch muscle, optimal eating conditions are met pretty
much as soon as you reach your final serving temperature
(say, 145°F for a chicken breast or 125°F for a steak). As
the meat is heated, it contracts, squeezing out moisture at a
rate that’s proportional to the temperature it’s raised to. So,
for example, you know that as soon as a steak hits 150°F, its
muscle fibers have contracted enough to squeeze out about
12 percent of its moisture, and there’s no turning back (see
here–here for more details).
Slow-Twitch muscle, on the other hand, comprises the
continually working muscles in an animal: The shoulders
and haunches that keep the animal upright and walking. The
tail muscles that keep the flies off. The muscles around the