Krampf
Experiment of the Week - Acid Hunt - 4/21/09
http://www.krampf.com
This
week, we are going on a hunt. No, we are not hunting for birds on
wires, as I did for this week's video. Instead, we are hunting
for
acid. The word "acid" usually makes people think of dangerous
chemicals, burning and corroding, but it describes an entire range of
chemicals.
OK,
so where are we going to look for acids? Not in your car,
although
there is acid in the car battery. Instead, we will look for acids
in
your refrigerator. The refrigerator! What would acid be
doing in
there? As we shall see, it is sitting there waiting for you to
consume
it.
Before
we start hunting, we really should know what an acid is. A
chemist
will tell you that an acid is a chemical that will give up a hydrogen
ion to another compound, called a base. That may seem
complicated, but
there is an easier way to identify acids. All we have to do is
look at
the word itself. Acid comes from acidus, the Latin word for
sour.
Acids have a sour taste.
Taste!
Wait a minute! Don't try tasting battery acid, or for that
matter, any
chemical that is just lying around. We will limit our tasting to
the
things in your refrigerator, but don't worry. We will find plenty
of
acids there.
Now
comes the fun part. Go open the refrigerator door, and we will
start
our hunt. Lets begin with the easy things. What do you see
that has a
sour taste?
If
your refrigerator is like mine, the first thing you will see is a jar
of pickles. Actually, in my refrigerator, you would see five or
six
jars of pickles, because I really like pickles. What do pickles
taste
like? Sour, right? Even sweet pickles have a sour taste,
mixed with
the sweet. Don't take my word for it. Have a pickle.
What makes
pickles taste sour? Vinegar, and most of the flavor of vinegar
comes
from acetic acid. As you taste your way though the refrigerator,
you
should find all sorts of things that contain vinegar, from salad
dressings to hot sauces to mustards.
OK,
now what else in here tastes sour? What about that lemon hiding
down
there on the bottom shelf? Lemons are certainly sour, which means
they
should contain acid, and they do. The acid in a lemon is citric
acid,
which makes sense since lemons are citrus fruit. Citric acid is
found
in other citrus fruits, such as limes, and grapefruits, but it is also
a common ingredient in jams, jellies, canned fruit, and even soft
drinks. While you are in the refrigerator, be sure to taste all
those
too.
We
have found two abundant acids, but don't stop now. Those soft
drinks
contain another kind of acid called carbonic acid. Carbonic acid
is
formed when you dissolve carbon dioxide in water, so anything that is
carbonated contains this acid.
The
citrus fruits also contain ascorbic acid, also known as vitamin
C. If
you have ever taken vitamin C tables, you will remember the sour
taste. Ascorbic acid is present in tomatoes and many other fruits
and
vegetables.
Looking
on down the shelves, you might see a carton of sour cream. A
quick
taste will tell you that it lives up to its name, so it must contain
acid, and it does. In this case, it contains lactic acid, an acid
formed when milk spoils, which is why we say that the milk has
soured.
It is also the acid that gives yogurt it’s pleasantly tart flavor.
If
you happen to have any strawberry rhubarb pie, the tartness of the
rhubarb comes from oxalic acid, which is also present in spinach,
beets, many kinds of berries, and even in chocolate.
If
you continue tasting and reading labels you will come across several
other acids, but by now you should realize how large a role acids play
in the flavors of our food. Even that bowl of cherry ice cream
that is
waiting for me contains citric acid, ascorbic acid, and oxalic acid.
Do
limit your tasting to the yummy stuff in the refrigerator (and the
freezer where the ice cream is kept), but since practically everything
in your refrigerator contains at least a little acid of some kind, you
should have no trouble satisfying any sour cravings. Well, my ice
cream is melting and the chocolate sauce is calling, so I will stop for
now.