Why do you get a skin form on top of hot milk?

Question

I really hate it!

Answer 1

its the protein breaking down, and only happens in commercial, pasturized milk. Commercial milk is heat pasturized and homogenized causing the fat proteins to bond together and become cohesive. When you heat it, those bonds break down, and the fat protein forms a thick skin. I use lovely fresh milk, straight from the cow, and this does not form a skin.

Answer 2

This skin formation is due to the loss of solids that the milk undergoes as it is warmed up.
As heat is applied to the milk, the proteins start to coagulate, and form a skin on the surface. After further heating, the skin dries because of evaporation, and forms a still firmer barrier.

Answer 3

The skin is formed by the molecules of fat in the milk which rise when milk is heated. When it cools these moleculed congeal to form the skin.

Skimmed milk does not boil over as it is the fat molecules which cause the bubbling up effect.

Answer 4

Milk is a colloidal mixture of water, lipids, carbohydrates and proteins. When you heat this mixture, evaporation goes on and the upper layer of milk gets supersaturated, high temperature denatures milk proteins and the colloid collapses. The "film" hence is a layer of clotted proteins and long chain carbohydrates, interpenetrated and fused by milk fats .

Answer 5

because of the fats....if u wanna stop it- make a cartouche( which is grease proof paper cut to the same size as the pan and then rested on top of the milk- this is good with stocks, soups and sauces like bechemel) or do it in the microwave

Answer 6

Ewwww

Answer 7

Crm of Mush soup does too...ewww

Answer 8

Because its being heated up it dry's it out.

Answer 9

i didnt know,but i always fight for the skin,its the best

Answer 10

I concur, it is good.