do egg whites foam?
you try to whip plain water into a foam, you wont have much
luck. Bubbles that form in plain water quickly pop. Thats
because water molecules stick together. Water molecules are electrically
attracted to each other. They wont spread out to form a bubble
film unless you add something that lessens the attraction.
egg white is about 90% water and 10% protein. The egg-white proteins
are long chains of amino acids that fold and curl into more or less
spherical tangles. When you beat an egg white, these proteins uncurl
and stretch out. (Click here to find
out why they uncurl.)
the proteins uncurl, they expose amino acids that were hidden in
the center of the tangle. Some of the amino acids repel water; these
are hydrophobic, or water-fearing amino acids. Some of the
amino acids are electrically charged and are attracted to water;
these are hydrophilic, or water-loving amino acids.
you beat the egg whites, you also whip bubbles into the mixture.
The water molecules and egg-white proteins bump around, jockeying
for position. The water molecules are attracted to each other and
to the hydrophilic amino acids on the proteins. While trying to
get close to each other and to the hydrophilic amino acids, the
water molecules squeeze the hydrophobic amino acids out. The best
place for the egg proteins is on the surface of the liquid, with
their hydrophobic amino acids sticking out into the air.
surface of each bubble film becomes crowded with egg proteins. The
water molecules are forced apart by these proteins. Since the attraction
between water molecules decreases with distance, the water molecules
dont stick together quite as wellthey can spread out
and make a bubble film.
the water molecules so that they spread out in bubble films is only
one step in making a meringue. The chicken egg contains a mixture
of proteins that makes meringue possible. Some of the proteins form
bonds with each other to create a stable network that keeps the
bubbles from popping. When the meringue is in the oven, another
proteinovoalbuminforms bonds that cause the meringue
does the temperature matter?
whites at room temperature can be beaten to a foam more easily than
cold egg whites.
is this dessert called Pavlova?
dessert is named after Anna Pavlova, a famous Russian ballerina.
Born in St. Petersburg in 1881, Pavlova overcame humble beginnings
and physical setbacks to become the most well-loved dancer of her
time, worshipped all over the world. This delicate dessert was created
in her honor. Her most famous role was in The Dying Swan,
a ballet that was choreographed especially for her. She died at
the age of 50, of pneumonia. She is famous for her last words. Moments
before her death, she said, “Bring me my swan costume.”
cant I use a plastic bowl?
interferes with the formation of a good foam—and fat clings
to plastic. No matter how carefully you clean a plastic bowl, odds
are good that a bit of grease remains behind. Its preferable—and
easier!—to use a glass or stainless steel bowl to produce
a fluffy meringue. Egg yolks also contain fat, so when you separate
the eggs, try to make sure that none of the yolk ends up in your
there any advantage to using a whisk?
gotten the best results from using a whisk with many thin wires.
It may be because the whisk incorporates more air into the foam
than a beater does.
not add sugar at the beginning?
sugar at the beginning can double the time you have to whip the
egg whites to get a foam. Thats because the sugar molecules
get in the way of the egg proteins. With sugar molecules in the
way, it takes longer for the proteins to find each other and form
meringue is cooking, sugar helps keep it stable by bonding with
water molecules and preventing them from escaping as water vapor.
Delaying the evaporation of water from the foam helps keep the foam
stable until it stiffens.
vinegar (or any other acid) can make the foam less likely to suffer
the consequences of overbeatinglumpiness, loss of water, and
collapse. These undesirable consequences result from too many bonds
forming between the egg proteins.
you add an acid to a mixture, you are essentially adding some positively
charged particles. These positively charged particles are hydrogen
ionshydrogen atoms that have lost an electron. The hydrogen
ions hop onto charged portions of the proteins and leave them uncharged.
Proteins that are electrically neutral are less likely to react
with other proteins.
oh! My meringue shell broke! How can I save this dessert?
your meringue shell gets too stiff and breaks apart, you can still
make a tasty dessert. Just chop up the fruit that you had intended
to put on top, whip the cream, break the meringue into large crumbs,
mix it all together, and call it ambrosia!
overbeaten egg whites be salvaged?
is not lost. As long as you havent added any other ingredients,
you can usually resurrect a foam by adding an extra egg white and
beating just until the mixture looks glossy and forms peaks again.”
Gardiner and Sue Wilson, The