all meats, as a burger cooks, this protein network tightens,
squeezing out liquids. Simultaneously, the fat begins to
render and liquefy, allowing it to be squeezed out right
along with the juices.
In a properly formed burger—one that is made with meat
that’s been ground right, kept chilled, and minimally
handled while shaping—the protein matrix is relatively
loose. Even once fat has been liquefied and juices have
been squeezed out of the protein network, they can remain
trapped in the patty, only getting released when you bite
into the burger, in much the same way that liquids can be
trapped in a sponge and only released when it is squeezed.
But press down on a burger during this phase, and the juices
come gushing out into the skillet or onto your coals. You’re
left with what amounts to a meat patty with the texture of a
sponge that’s been run through a wringer.
All burgers will lose weight as you cook them—it’s not
possible to hold on to all the liquefied fat and exuded juices.
In my testing, 4-ounce burgers that started as round pucks
and were smashed down to ½-inch thickness any time
before 30 seconds still lost a little over 20 percent of their
weight during cooking. But this is comparable to burgers of
the same weight and thickness that were cooked with no
smashing at all. Both burgers tasted quite juicy, while the
smashed burger (obviously) had better flavor.
SMASH TIME VERSUS FINAL WEIGHT