browning.
While it’s true that given enough time you can brown
even a nonsmashed burger, there are a couple problems: If
the heat is too high, the browning will be uneven—at worst,
the bits of meat directly in contact with the skillet or griddle
will burn before the bits elevated above it can even begin to
brown. With lower heat, you can get more even browning,
but it takes longer—long enough that your burger will end
up overcooking in the middle (and overcooking is the real
path to dry burgers).
Smashing allows you to get a deep brown crust before the
interior overcooks, even with a relatively small patty.
The Juice Is Loose
So, when is it not a good idea to smash? We all have a
pretty good idea of this, but I cooked through a couple
dozen burgers, smashing them at various stages in order to
make sure. The results? If you don’t want to lose juices, you
must smash within the first 30 seconds of cooking.
When ground beef is cold, its fat is still solid and its juices
are still held firmly in place inside small chopped-up
segments of muscle fibers. That’s the reason why you can
push and press on raw ground meat without squeezing out
too much liquid, and the reason why you can smash a
burger during the initial phase of cooking without fear of
losing moisture.
But what happens as the meat warms up?
When you look at a burger under a microscope, you see
what basically amounts to an interconnected network of
proteins interspersed with fat and water-based liquids. Like