The Strange History of Cheese
By Andrea
Thompson,
LiveScience Staff Writer
For
many, the mild, slightly nutty flavor of
Gruyère is the perfect addition to
a steaming bowl of French onion soup or
a ham sandwich, but for the medieval peasants
who first created it, the flavor was secondary
to matters of survival and location.
Gruyère
resulted from the historic collision of
food scarcity and a mountainous geography,
yielding a distinct and rigorous cheese-making
process.
In
fact, all cheese types-there are now more
than 1,400--initially arose due to the unique
constraints forced by geography and the
human effort to preserve the valuable commodity
that is milk, says food scientist Paul Kindstedt,
of the University of Vermont
Cheese
recipes initially arose as a way to preserve
the nutritional
value in milk for longer periods
of time, so the number of types primarily
reflects the number of struggling pre-industrial
communities that successfully devised a
method to achieve this given their local
climate, resources and terrain.
At
a recent lecture at the New York Academy
of Sciences in Manhattan, Kindstedt, of
the University of Vermont, elaborated:
"Traditional
cheeses always originated because cheese
makers had to adapt to the cultural and
environmental constraints of their local
world," he said. "And they had
to do things differently from one region
to the next, because cheese makers in different
regions face different constraints."
His
lecture detailed the cheese making process
and and the new work he is doing to reveal
the history of cheese-making practices and
how it was shaped by what he calls the universal
scientific principles of cheese.
What
is cheese?
Those
principles derive from the unusual properties
of milk, cheese's primary ingredient.
"Whether
you're talking about milk
from a cow, goat, sheep, water
buffalo, camel, yak or any other mammal
thats milk is used for cheese-making, all
milk contains five basic components,"
Kindstedt said.
Those
components are water, lactose (or "milk
sugar"), fat, protein and minerals.
The
protein in milk is of two types: casein
and whey. Along with fat, casein makes up
the bulk of the solid part of cheese, while
whey is essentially the liquid left after
the milk curdles.
Some
of casein's amino acid chains strongly bind
the mineral calcium phosphate (the main
component of bones and teeth), which holds
casein molecules together in larger spheres
called micelles.
The
surface of the micelles is hydrophilic,
or water-loving (this is why milk
is white-the surface keeps the
casein suspended in water).
How
cheese is made
Eight steps have made up the cheese making
process for every cheese since they were
first made, and those steps have three objectives:
to expel water, to de-mineralize the casein
with bacterial acids, and to add salt.
The
exact target for each objective is different
for each type of cheese. Each has its own
target water content, acid content and salt
content-all of these things affect the cheese's
ripening process and which microbes
flourish with in it, ultimately influencing
its final aroma, texture and flavor.
"So
you've got to get these three parameters
right, or the newly-made cheese, which starts
out very curdy, very uninspiring, very bland,
will never ripen into what it's intended
to be," Kindstedt said.
Step
1-Setting: Bacteria (either already
swimming around in the milk or added to
it) and enzymes derived from the stomach
linings of milk-producing mammals and called
rennet are added to the milk. The rennet
shaves off the hydrophilic surface layer
of the casein, causing the micelles to coagulate
into what is called the curd.
For
the rest of the eight steps, squeezing out
the water, or liquid whey, from the cheese
is a major goal, depending on the type of
cheese. For example, cheddar cheese starts
with a moisture content of 87 percent and
that has to be reduced down to 37 percent,
while brie retains more of its whey.
Step
2-Cutting: The curd is "cut"
into smaller particles-the smaller the particle,
the less water it holds, thus more whey
is expelled from the curd. (So drier cheeses
like cheddar will be cut into smaller particles
than moister cheeses like brie.)
Step
3-Cooking: The curd is heated and
stirred, which expels more whey.
"For
some cheeses like Parmigiano Reggiano, they're
cooked to very high temperatures with considerable
stirring for long periods of time,"
Kindstedt said. "At the other extreme,
some cheeses like brie, traditional brie,
receive essentially no heating, no stirring,
no cooking."
Step
4-Draining: Draining separates
more whey from the curd, depending on how
dry the final cheese is supposed to be.
Step
5-Knitting: This step overlaps
with draining; as the whey drains away,
the curd particles come into contact with
each other and stick into a bigger mass.
Step
6-Pressing: Weight is applied to
the cheese to give it its final shape and
to squeeze out more whey, depending on the
type of cheese of course.
Step
7-Salting: Salt
can be added by sprinkling or rubbing it
on the cheese or by submerging the cheese
in a salt brine; it continues to draw out
whey.
Step
8-Special applications: These can
include applying specific environmental
conditions such as humidity and temperature
or physical manipulations like turning the
cheese while it ages.
The
story of Gruyère
So what about Gruyère-just how did
its creators come to create this unique
cheese? In the Middle Ages, the peasants
in small feudal villages in the Gruyère
region of eastern Switzerland began to use
grassy meadows in the mountains to graze
their cattle.
But
since it was impractical, not to mention
tiring, for each peasant to march uphill
every day to milk their cows, a few peasants
were appointed to watch the whole village's
herd, milk
the cows, and make cheese from
the milk every day.
Because
the cheese would have to be kept in the
mountains until the end of the summer, it
had to be long-lived; and to make the unsteady
trip down the mountain, it had to be large
and durable so as to avoiding chipping and
cracking.
"The
cheese was deliberately built to last, so
to speak," Kindstedt said.
But "in order to make the cheese long-lived,
large and durable, it had to be low in moisture
content," he added. "The cardinal
rule of cheese: the higher the moisture
content, the shorter the shelf life."
The
peasants had to use fresh milk every day,
Kindstedt has surmised, which meant there
was a higher moisture content as the cheese
developed' and they could only haul so much
salt up the mountain with them at the beginning
of the summer, so they had to use it sparingly.
To
get around these limitations, Gruyère
makers created an elaborate cutting technique
"that was designed to produce a very
small, pea-sized curd particle" to
expel water, Kindstedt said.
They
also cooked and stirred the cheese at extremely
high temperatures and for long periods of
time to squeeze more water
out-not an easy process in those times.
"It's
hot, it's physically demanding, if not downright
exhausting," Kindstedt said. "It's
not something cheese makers would have developed
or chosen to do unless they had a real incentive
to do it this way, or unless they had no
choice," which was the case for the
Gruyère makers and is the reason
Gruyère even exists.
In
other words, whatever cheese you happen
to enjoy munching, be it Gruyère,
asiago or muenster, "you can be certain
that there's a good reason that that cheese
originated in history when it did and where
it did," Kindstedt said.
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