Firstly, it is because the tool used to whip the egg whites has touched water, which leads to thinner and thinner whipping.

Secondly, there is grease in the whipping container, even if it is just a little bit, which can easily cause the egg whites to be particularly thin. Or there is some egg yolk liquid inside the egg white, not completely separated from the egg white, so that also can not be whipped up. Or the temperature of the egg white is not suitable, the general temperature is 18 to 20 degrees. Whether the temperature is too high, or the temperature is too low, will not be able to whip the egg whites to the desired effect.

Egg white whipping notes

All utensils for whipping egg whites should be scalded with hot water and then wiped dry to prevent oil from affecting egg white foam. The principle is: the structure of the oil is more stable, has a strong ability to wrap, and hydrophobicity, can prevent the protein and air combination. Even if it is whipped, the organization of whipped egg whites at this time is unstable and prone to collapse.

When the egg white and yolk are separated, there can't be any yolk inside the egg white, or it will also affect the degree of protein whipping. This is also because the yolk also has oil as its main ingredient, so it will affect the egg white whipping.