ChemMatters | DECEMBER 2017/JANUARY 2018 7
Ba dum bump. Thank you, thank you— we’ll be here all article. Now, get ready for some cheesy science and
maybe a few more cheesy jokes.
We love cheese. Love it, love it, love it. And
we are eating more of it—in the past 30 years,
the average cheese consumed per person in
the United States has increased 41%, up to 36
pounds of cheese per person. Mozzarella consumption was up 178% in the same period.
But cheese is kind of weird. It is storable
milk. It can last weeks or years longer than
milk and there is such a variety of cheese.
But when did we start eating cheese? We
don’t know the exact origin but at some point,
someone must have thought, “You know that
stuff at the bottom of the milk? That stuff that
dried out and sat for weeks? I’m going to eat
that!” And when they survived, proto-cheese
Humans have used practical knowledge of
chemistry and biology to preserve food for
millennia, long before refrigeration and other
modern technology. To make cheese, bacteria
digest sugars in milk and produce lactic acid.
The additional lactic acid lowers the pH and
hinders the growth of harmful organisms.
By turning milk into cheese, its shelf life is
extended from about three weeks to two
decades, or even longer.
All cheese starts as milk (Fig.1).
The primary sources are milk from cows,
goats, and sheep, though other mammals
such as water buffalo are also used around
the world for milk production.
Basically, Basic Cheese is
The basic steps in cheesemaking are: adding beneficial bacteria to milk, coagulating
the milk into a soft white substance called
curd, and pressing and cutting curd into the
finished cheese shape. But to get a delicious
final product, the milk must be at the right
temperature and the right pH at the right time.
“You cannot fully understand cheese and
cheesemaking unless you understand acidity
and pH,” says Paul Kindstedt, professor at
the Vermont Institute for Artisan Cheese, in
The pH measures the concentration of
hydrogen ions (H+) in a solution, with most
solutions between the range of 0 and 14.
The more acidic the solution, the lower the
pH, with 7 considered “neutral” and above 7,
“basic.” Milk has a pH between 6. 6 and 6.7.
pH is a logarithmic scale, so one unit differs
by a factor of 10. A pH of 6 has ten times the
H+ concentration than a solution with a pH
Did you hear about the explosion at the cheese factory?
There was de brie everywhere!
By Sarah Mullen Gilbert
Minerals and other
Minerals and other
Whole milk Cheese
Figure 1. Cow’s milk compared to cheese. Cow’s milk is mostly water; cheesemaking removes much of the water and concentrates the remaining fat, protein,
and other components.
Scan the man on the
bench with the LinkReader mobile app
to see a video that
explains how to
make the perfect grilled