During heating some amount of water gets converted into
vapour and the bubbles of water vapour rise to the top but the heat is
conducted away by the layer of water and by the fat droplets that have a higher
boiling point than water.
The vapour gets trapped in the creamy upper layer. As the
milk is heated further the water vapour expands and thick foam is produced on
the top.
As the milk is boiled continuously the water, which boils at
100 degrees Centigrade, produces more water vapour and pressure builds up in the
boiling milk so that the vapour pressure raises the creamy layer. So the milk
pushes the creamy layer out and milk spills out. Courtesy : The Hindu
No comments:
Post a Comment