Egg White Foam
The physical stress of beating egg white can create a foam. There are two types of physical stress caused by beating them with a whisk, the first being that the whisk drags the liquid through itself, creating a force that unfolds the protein molecules. This process is called denaturation. The second stress comes from the mixing of air into the whites, which causes the proteins to come out of their natural state. These denatured proteins gather together where the air and water meet and create multiple bonds with the other unraveled proteins, and thus become a foam, holding the incorporated air in place. This is because the proteins consist of amino acids; some are hydrophilic (attracted to water) and some are hydrophobic (repelled by water). This process is called coagulation.
When beating egg whites, they are classified in three stages according to the peaks they form when the beater is lifted: soft, firm, and stiff peaks. Overbeaten eggs take on a dry appearance, and will eventually collapse. Egg whites will not beat up correctly if they are exposed to any form of fat, such as cooking oils or the fats contained in egg yolk.
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Famous quotes containing the words egg, white and/or foam:
“If there was one egg in it there were nine,
Torpedo-like, with shell of gritty leather,
All packed in sand to wait the trump together.”
—Robert Frost (1874–1963)
“With sweetest milk, and sugar, first
I it as mine own fingers nurst.
And as it grew, so every day
It wax’d more white and sweet than they.
It had so sweet a Breath!”
—Andrew Marvell (1621–1678)
““To dine!” she shrieked in dragon-wrath.
“To swallow wines all foam and froth!
To simper at a table-cloth!”
Say, can thy noble spirit stoop
To join the gormandising troop
Who find solace in the soup?”
—Lewis Carroll [Charles Lutwidge Dodgson] (1832–1898)